Click the link to read the guest column on the New York Times website (Chukwumerije Okereke). Here’s an excerpt:
Several environmentalists last year presented Africa’s leading climate negotiators with a bold idea: A technology called solar geoengineering could protect their countries from the worst effects of climate change, they said. While insisting they were impartial, representatives from the Carnegie Climate Governance Initiative said that these technologies, which claim to be able to re-engineer the climate itself, either by dimming the sun’s rays or reflecting sunlight away from the earth, could quickly and cheaply turn the tide of dangerously rising temperatures — and that poor countries might have the most to gain.
It wasn’t the first time Westerners have tried to persuade Africans that solar engineering projects may be in our best interest. And it won’t be the last. In May, another international nonprofit, the Climate Overshoot Commission, headquartered in Paris, is hosting an event in Nairobi to help drum up support for research on solar geoengineering and other related technologies it says could be helpful in reducing risks when the world exceeds its global warming targets.
As a climate expert, I consider these environmental manipulation techniques extremely risky. And as an African climate expert, I strongly object to the idea that Africa should be turned into a testing ground for their use. Even if solar geoengineering can help deflect heat and improve weather conditions on the ground — a prospect that is unproven on any relevant scale — it’s not a long-term solution to climate change. It sends a message to the world that we can carry on over-consuming and polluting because we will be able to engineer our way out of the problem.
The solar engineering technology attracting the most attention would use balloons or aircraft to spray large quantities of aerosols — tiny particles of, for example, sulfur dioxide or engineered nanoparticles — into the stratosphere to dim the sunlight. It’s called solar radiation management and it’s highly speculative.Without using the whole earth as a laboratory, it’s impossible to know whether it would dim anything, let alone how it would affect ecosystems, people and the global climate.
These technologies would also theoretically need to be deployed essentially forever to keep warming at bay. Stopping would unleash the suppressed warming of the carbon dioxide still accumulating in the atmosphere in a temperature spike known as “termination shock.” One study found that the temperature change after ending solar radiation management could be up to four times as large as what’s being caused by climate change itself.
The other risk is that geoengineering will divert attention and investments from building renewable energy and other climate solutions in Africa. The continent has received only 2 percent of global investments in renewable energy in the last two decades, and the lack of access to capital is perhaps the biggest obstacle for countries that would like to cut down on fossil fuels.
Click the link to read the article on the Carbon Brief website (Aruna Chandra, Daisy Dunne, Orla Dwyer, Simon Evans, Robert McSweeney, Ayesha Tandon, and Giuliana Viglione)
The final part of the world’s most comprehensive assessment of climate change – which details the “unequivocal” role of humans, its impacts on “every region” of the world and what must be done to solve it – has now been published in full by the UN’s Intergovernmental Panel on Climate Change (IPCC).
The synthesis report is the last in the IPCC’s sixth assessment cycle, which has involved 700 scientists in 91 countries. Overall, the full cycle of reports has taken eight years to complete.
The report sets out in the clearest and most evidenced detail yet how humans are responsible for the 1.1C of temperature rise seen since the start of the industrial era.
It also shows how the impacts of this level of warming are already deadly and disproportionately heaped upon the world’s most vulnerable people.
The report notes that policies in place by the end of 2021 – the cut-off date for evidence cited in the assessment – would likely see temperatures exceed 1.5C this century and reach around 3.2C by 2100.
In many parts of the world, humans and ecosystems will be unable to adapt to this amount of warming, it says. And the losses and damages will “escalate with every increment” of global temperature rise.
But it also lays out how governments can still take action to avoid the worst of climate change, with the rest of this decade being crucial for deciding impacts for the rest of the century. The report says:
“There is a rapidly closing window of opportunity to secure a liveable and sustainable future for all…The choices and actions implemented in this decade will have impacts now and for thousands of years.”
The report shows that many options for tackling climate change – from wind and solar power to tackling food waste and greening cities – are already cost effective, enjoy public support and would come with co-benefits for human health and nature.
At a press briefing, leading climate scientist and IPCC author Prof Friederike Otto said the report highlights “not only the urgency of the problem and the gravity of it, but also lots of reasons for hope – because we still have the time to act and we have everything we need”.
Carbon Brief’s team of journalists has delved through each page of the IPCC’s AR6 full synthesis report to produce a digestible summary of the key findings and graphics.
The synthesis report is the final part of the IPCC’s sixth assessment cycle. It “integrates” the main findings of the three working group reports, which have been published over the last 18 months or so:
The synthesis report is much shorter than the full assessment reports. The combined length of the “summary for policymakers” (SPM) – a short, non-technical synopsis – and the underlying report clocks in at 122 pages. This is longer than the 42.5 pages that were planned (pdf), but a fraction of the assessment reports that can top 3,000 pages. As with the assessment reports, the synthesis report has been through several rounds of review by experts and governments.
The report’s SPM was signed off via a line-by-line approval session involving authors and government delegates last week in Switzerland.
However, unlike the assessment reports, the session also approved the underlying full report “section by section”. It was also the IPCC’s first approval session since the Covid-19 pandemic that was held in person.
The approval process was scheduled to be completed on Friday 17 March, but overran – despite multiple “night sessions” and “round-the-clock deliberations”. The SPM was finally approved on the morning of Sunday 19 March in a “sparsely attended room”, as many developing country delegates had already left the venue, Third World Network reported. “People who have to contribute have left the meeting,” said India’s representatives in the early hours before the closing plenary.
Once the SPM was approved, there was then a “huge moment of panic” around whether “it would at all be possible to do the approval of the long report”, Otto said:
“We all almost died of adrenaline poisoning during [Sunday], but then it was approved quite straightforwardly.”
(The Earth Negotiations Bulletin has published a summary of the discussions during the approval session. This is referenced frequently in this article.)
The synthesis report shares the IPCC’s “calibrated language” that the assessment reports use to communicate levels of certainty behind the statements it includes.
The findings are given “as statements of fact or associated with an assessed level of confidence”, based on scientific understanding. The language indicates the “underlying evidence and agreement”, the report explains:
“A level of confidence is expressed using five qualifiers: very low, low, medium, high and very high, and typeset in italics, for example, medium confidence.
“The following terms have been used to indicate the assessed likelihood of an outcome or result: virtually certain 99-100% probability; very likely 90-100%; likely 66-100%; more likely than not >50-100%; about as likely as not 33-66%; unlikely 0-33%; very unlikely 0—10%; and exceptionally unlikely 0-1%. Additional terms (extremely likely 95-100%; more likely than not >50-100%; and extremely unlikely 0-5%) are also used when appropriate.”
The WG1 report “assessed the climate response to five illustrative scenarios based on Shared Socioeconomic Pathways (SSPs) that cover the range of possible future development of anthropogenic drivers of climate change found in the literature”, the synthesis explains:
“The high and very high GHG emissions scenarios (SSP3-7.0 and SSP5-8.5) have CO2 emissions that roughly double from current levels by 2100 and 2050, respectively. The intermediate GHG emissions scenario (SSP2-4.5) has CO2 emissions remaining around current levels until the middle of the century. The very low and low GHG emissions scenarios (SSP1-1.9 and SSP1-2.6) have CO2 emissions declining to net-zero around 2050 and 2070, respectively, followed by varying levels of net-negative CO2 emissions.”
In contrast, the WG3 report assessed “a large number of global modelled emissions pathways…of which 1,202 pathways were categorised based on their projected global warming over the 21st century, with categories ranging from pathways that limit warming to 1.5C with more than 50% likelihood with no or limited overshoot (C1) to pathways that exceed 4C (C8)”.
The table below, taken from the synthesis report, shows how these pathways relate to the SSPs and their predecessors, the Representative Concentration Pathways (RCPs).
The synthesis report is the final product of the IPCC’s sixth assessment cycle. Its delay from the planned publication in September last year for “management reasons” – and the lack of transparency surrounding these issues – resulted in “unusually blunt statements of discontent from governments” about the IPCC’s impact and credibility, the Earth Negotiations Bulletin reported at the time.
Nonetheless, governments agreed at a September meeting that the IPCC’s seventh assessment cycle (AR7) will begin in July this year and will have a length of between five and seven years. The end of AR6 and the start of AR7 will see the election of a new IPCC leadership team – including chair, vice-chairs and working group co-chairs. The first full assessment reports of AR7 would likely not be expected until 2027 or 2028.
The SPM says with high confidence that human activities have “unequivocally caused global warming”.
2. How is the Earth’s climate changing?
This statement – first made in the IPCC’s WG1 report – is the strongest wording to date about the role of human activities on observed warming from any IPCC assessment cycle.
Overall, the report says that global surface temperature in 2011-20 averaged at 1.09C above 1850-1900 levels – with a 1.59C rise seen over land and a 0.88C rise over the ocean. It adds, with high confidence, that “global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2000 years”.
According to the Earth Negotiations Bulletin, delegates “disagreed on how much information to include” in the SPM sub-paragraph on global surface temperature increases. The bulletin outlines the lengthy discussion needed to finalise this section of the text – including decisions on whether to use the “more precise” 1.09C or the rounded 1.1C figure and warnings that the addition of extra sentences “overloaded the sub-paragraph with numbers and diluted the message”.
The SPM also discusses the observed changes and impacts of climate change to date. It makes the following statement with high confidence:
“Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred. Human-caused climate change is already affecting many weather and climate extremes in every region across the globe. This has led to widespread adverse impacts and related losses and damages to nature and people.”
It says that global average sea levels increased by 0.2 metres between 1901 and 2018. Sea level rise accelerated over this time, from a rate of 1.3mm per year over 1901-71 to 2.7mm per year over 2006-18, it adds.
The SPM for the AR6 synthesis report is longer than its AR5 counterpart (pdf) and contains more numbers in its section on observed changes in the climate system.
For example, the AR5 report does not quantify the rate of acceleration of sea level rise, instead saying that “the rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence)”.
Meanwhile, the SPM says human influence has likely increased the chance of “compound” extreme events since the 1950s, including increases in the frequency of concurrent heatwaves and droughts.
The SPM has very high confidence that “increases in extreme heat events have resulted in human mortality and morbidity” in all regions. It adds that extreme temperatures also cause mental health challenges, trauma and the loss of livelihoods and culture. The report also has high confidence that climate change is “contributing to humanitarian crises where climate hazards interact with high vulnerability”.
Elsewhere, the report has high confidence that animal and human diseases including zoonoses – infections that pass between animals and people – “are emerging in new areas” and very high confidence that “the occurrence of climate-related food-borne and water-borne diseases has increased”.
The SPM warns that climate and weather extremes are “increasingly driving displacement in Africa, Asia, North America (high confidence), and Central and South America (medium confidence), with small island states in the Caribbean and South Pacific being disproportionately affected relative to their small population size(high confidence)”.
The authors write that hot extremes have intensified in cities and that they have high confidence that the observed adverse impacts are “concentrated amongst economically and socially marginalised urban residents”.
The report elaborates, saying it has high confidence that “urban infrastructure including transportation, water, sanitation and energy systems have been compromised by extreme and slow-onset events, with resulting economic losses, disruptions of services and impacts to well-being”.
The table below shows observed changes in the climate and their attribution to human influence. Darker colours indicate a higher confidence in the changes and their human influence. Notably, the table lists “warming of the global climate system since pre-industrial times” as a “fact”.
The report has high confidence that climate change has hindered efforts to meet the Sustainable Development Goals by reducing food security, changing rainfall patterns, melting bodies of ice such as glaciers and driving more intense and frequent extreme weather events.
For example, the report says that “increasing weather and climate extreme events have exposed millions of people to acute food insecurity and reduced water security”. (For more on how climate change is affecting extreme weather, see Carbon Brief’s coverage of the IPCC’s WG1 report.)
The report also says that “substantial damages, and increasingly irreversible losses” have already been sustained. For example, it has very high confidence that approximately half of the species assessed globally have shifted polewards or to higher elevations. It has medium confidence that impacts on some ecosystems are “approaching irreversibility” – for example the impacts of hydrological changes resulting from glacial retreat.
The report also has high confidence that “economic impacts attributable to climate change are increasingly affecting peoples’ livelihoods and are causing economic and societal impacts across national boundaries”.
3. How are human-caused emissions driving global warming?
The report states as fact – that is, with no calibrated language – that “human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming”.
In other words, the report states, “human-caused climate change is a consequence of more than a century of net GHG emissions from energy use, land-use and land use change, lifestyle and patterns of consumption, and production”.
Specifically, the report explains that humans have contributed to 1.07C of the observed warming between 1850-1900 and 2010-19, with a likely range of 0.8-1.3C. As the total observed warming over the same period is 1.06C, this means that humans have caused 100% of the long-term global warming to date.
This conclusion is in line with the synthesis report (pdf) of the IPCC’s fifth assessment report (AR5), published in 2014, which said:
“The best estimate of the human-induced contribution to warming is similar to the observed warming over [1951-2010].“
That the influence of human activity is marginally larger than the observed temperature rise reflects the mix of impacts that an industrialised society is having. The warming impact of the GHGs that human activity has produced is likely to be in the range of 1.0-2.0C. But then there is also the cooling influence of other “human drivers (principally aerosols)”, the report notes.
Aerosols include tiny particles – such as soot – that are produced from cars, factories and power stations. They tend to have an overall cooling effect on the Earth’s climate by scattering incoming sunlight and stimulating clouds to form. These human drivers could have contributed to a cooling of 0.0-0.8C, the IPCC says.
The net cooling effect of human-caused aerosols “peaked in the late 20th century”, the report notes with high confidence.
Natural influences on the climate had only a small influence on the long-term trend in global temperature, the reports says, with fluctuations in the sun and volcanic activity causing between -0.1C and 0.1C of temperature change and other natural variability causing between -0.2C and 0.2C.
The increase in concentrations of GHGs in the atmosphere since around 1750 “are unequivocally caused by GHG emissions from human activities over this period”, the IPCC says:
“In 2019, atmospheric CO2 concentrations (410 parts per million) were higher than at any time in at least 2m years (high confidence), and concentrations of methane (1866 parts per billion) and nitrous oxide (332 parts per billion) were higher than at any time in at least 800,000 years (very high confidence).”
The figure below shows “the causal chain from emissions to resulting warming of the climate system”. The bottom panel shows the increase in GHGs over 1850-2019, the middle panel shows the resulting rise in atmospheric greenhouse gas emissions, the top left panel shows the change in global surface temperature since 1850 and the top right panel separates the warming out into its different contributing factors.
The report says with high confidence that “land and ocean sinks have taken up a near-constant proportion (globally about 56% per year) of CO2 emissions from human activities over the past six decades”. However, looking to the future, it adds:
“In scenarios with increasing CO2 emissions, the land and ocean carbon sinks are projected to be less effective at slowing the accumulation of CO2 in the atmosphere (high confidence).
“While natural land and ocean carbon sinks are projected to take up, in absolute terms, a progressively larger amount of CO2 under higher compared to lower CO2 emissions scenarios, they become less effective, that is, the proportion of emissions taken up by land and ocean decreases with increasing cumulative net CO2 emissions (high confidence).”
In 2019, global net emissions of GHGs clocked in at 59bn tonnes of CO2 equivalent (GtCO2e), the report says. This is 12% higher than in 2010 and 54% higher than in 1990, with “the largest share and growth in gross GHG emissions occurring in CO2 from fossil fuels combustion and industrial processes followed by methane”.
The report says, with high confidence, that GHG emissions since 2010 have increased “across all major sectors”. It continues:
“In 2019, approximately 34% (20GtCO2e) of net global GHG emissions came from the energy sector, 24% (14GtCO2e) from industry, 22% (13GtCO2e) from AFOLU, 15% (8.7GtCO2e) from transport and 6% (3.3GtCO2e) from buildings.”
However, although average annual GHG emissions between 2010 and 2019 were “higher than in any previous decade”, the rate of growth during this period (1.3% per year) “was lower than that between 2000 and 2009” (2.1% per year), the report notes. This sentence – which also featured in the WG3 report – was added during the approval session at the request of China, the Earth Negotiations Bulletin reported.
Historical contributions to global GHGs “vary substantially across regions” and “continue to differ widely”, the authors note.
In 2019, around 35% of the global population were in countries emitting more than nine tonnes of CO2e per capita – excluding CO2 emissions from land use, land-use change and forestry (LULUCF), the report says.
In contrast, 41% were in countries emitting less than three tonnes of CO2e. It adds that least developed countries (LDCs) and small island developing states (SIDS), in particular, have much lower per-capita emissions (1.7 and 4.6 tonnes of CO2e, respectively) than the global average (6.9 tonnes), excluding CO2 from LULUCF.
Perhaps most starkly, the authors note with high confidence:
“The 10% of households with the highest per-capita emissions contribute 34-45% of global consumption-based household GHG emissions, while the bottom 50% contribute 13-15%.”
The regional variations in emissions are illustrated by the figure below, which shows historical contributions (top-left), per capita emissions in 2019 (top-right) and global emissions since 1990 broken down by emissions (bottom). (For more on historical responsibility for emissions, see Carbon Brief’s analysis from 2021.)
During the approval session, France – supported by around 15 other countries, including the US and Canada – requested that this figure was elevated into the SPM “to provide a clear and necessary narrative about the causes of warming”, the Earth Negotiations Bulletin reported. However, Saudi Arabia, India and China opposed the move and a subsequent huddle was “unable to reach consensus”.
4. How much hotter will the world get this century?
The world will continue to get hotter “in the near term (2021-40)”, the report says, “in nearly all considered scenarios and pathways” for greenhouse gas emissions.
Crucially, however, there is a choice over how hot it gets by the end of the century. As the synthesis report explains: “Future warming will be driven by future emissions.”
The amount of warming this century largely depends on the amount of greenhouse gases that humans release into the atmosphere in the future “with cumulative net CO2 dominating”.
The report looks at a range of plausible futures, known as the shared socioeconomic pathways (SSPs), spanning very low to very high emissions. (See: What is this report?)
If emissions are very low (SSP1-1.9), then warming is expected to temporarily “overshoot” 1.5C by “no more than 0.1C” before returning to 1.4C in 2100, the report says.
If emissions are very high (SSP5-8.5), warming could reach 4.4C in 2100. (See below for more on what it would take for the world to follow these different emissions pathways.)
Notably, there is less uncertainty in these projections than there was in AR5. This is because the IPCC has narrowed the range of “climate sensitivity”, using observations of recorded warming to date and improved understanding of clouds.
The alternative emissions futures are shown in the figure below, which illustrates the 1.1C of warming to date and potential increases to 2100 in the style of the famous “climate stripes”.
The figure also illustrates the warming that would take place during the lifetimes of three representative generations born in 1950, 1980 and 2020.
While limiting warming in line with global targets would require “deep and rapid, and, in most cases, immediate greenhouse gas emissions reductions in all sectors this decade”, these efforts would not be felt for some time. The SPM explains with high confidence:
“Continued greenhouse gas emissions will lead to increasing warming…Deep, rapid and sustained reductions in greenhouse gas emissions would lead to a discernible slowdown in global warming within around two decades.”
This delay means that global temperatures are more likely than not to reach 1.5C during 2021-40, the report says, even if emissions are very low.
The report does not give specific “exceedance” years that breach 1.5C for each emissions pathway. (The 1.5C limit of the Paris Agreement relates to long-term averages, rather than warming in a single year.)
The SPM explains that for very low, low, intermediate and high emissions, “the midpoint of the first 20-year running average period during which [warming] reaches 1.5C lies in the first half of the 2030s”. If emissions are very high, it would be in “the late 2020s”.
Similarly, the report says warming will exceed 2C this century “unless deep reductions in CO2 and other GHG emissions occur in the coming decades”.
At the other end of the spectrum, it has “become less likely” that the world will match the very high emissions scenario (SSP5-8.5), where warming exceeds 4C this century.
The report says, with medium confidence, that emissions could only reach such high levels if there is “a reversal of current technology and/or mitigation policy trends”.
However, it says 4C of warming is possible with lower emissions, if carbon cycle feedbacks or climate sensitivity are larger than thought. It explains in a footnote to the SPM:
“Very high emissions scenarios have become less likely, but cannot be ruled out. Warming levels >4C may result from very high emissions scenarios, but can also occur from lower emission scenarios if climate sensitivity or carbon cycle feedbacks are higher than the best estimate.”
In addition to the path of greenhouse gas emissions, changing emissions of “short-lived climate forcers” (SLCFs) can also add to near- and long-term warming, the report says with high confidence. SLCFs include methane, aerosols and ozone precursors, it explains.
There have been concerns that efforts to cut greenhouse gas emissions could also reduce output of cooling aerosols, “unmasking” additional warming. The report plays down this risk:
“Simultaneous stringent climate change mitigation and air pollution control policies limit this additional warming and lead to strong benefits for air quality (high confidence).”
5. What are the potential impacts at different warming levels?
With every extra bit of global warming, extremes facing the world will become larger, the report says.
For example, it says with high confidence that continued climate change will further intensify the global water cycle, driving changes to monsoons and to very wet and very dry weather.
As temperatures rise, natural land and ocean carbon sinks will be less able to absorb emissions – worsening warming further, the report says with high confidence.
Other changes to expect include further reductions in “almost all” the world’s ice systems, from glaciers to sea ice (high confidence), further global sea level rise (virtually certain), and increasing acidity and decreasing oxygen availability in the oceans (virtually certain).
Every world region will experience more climate impacts with every bit of further warming, the report says.
Compound heatwave and drought extremes are expected to become more frequent in many regions, the report says with high confidence.
Extreme sea level events that currently occur once in every 100 years are expected to take place at least annually in more than half all measurable locations by 2100, under any future emissions scenario, it says with high confidence. (Extreme sea level events include storm surges and flooding.)
Other projected changes include the intensification of tropical storms (medium confidence) and increases in fire weather (high confidence), according to the report.
It says that the natural variability of the Earth’s climate will continue to act alongside climate change, sometimes worsening and sometimes masking its effects.
The graphic below, from the report’s SPM, illustrates some of the regional impacts of climate change at 1.5C, 2C, 3C and 4C of global warming. (Current policies from governments have the world on track for around 2.7C of warming.)
In the near term, every world region is expected to face further increases in climate hazards – with rising risk for humans and ecosystems (very high confidence), the report says.
Risks expected to increase in the near-term include heat-related deaths (high confidence), food-, water- and vector-borne diseases (high confidence), poor mental health (very high confidence), flooding in coastal and low-lying cities (high confidence) and a decrease in food production in some regions (high confidence).
At 1.5C, risks will increase for “health, livelihoods, food security, water supply, human security and economic growth”, the report says. At this level of global warming, many low-elevation and small glaciers around the world would lose most of their mass or disappear, the report says with high confidence. Coral reefs are expected to decline by a further 70–90%, it adds with high confidence.
At 2C, risks associated with extreme weather events will transition to “very high”, the report says with medium confidence. At this level of warming, changes in food availability and diet quality could increase nutrition-related diseases and undernourishment for up to “hundreds of millions of people”, particularly among low-income households in sub-Saharan Africa, south Asia and central America, the report says with high confidence.
At 3C, “risks in many sectors and regions reach high or very high levels, implying widespread systemic impacts”, the report says. The number of endemic species in biodiversity hotspots at a very high risk of extinction is expected to be 10 times higher than at 1.5C, it says with medium confidence.
At 4C and above, around half of tropical marine species could face local extinction, the report says with medium confidence. Around four billion people could face water scarcity, it says with medium confidence. It adds that the global area burned by wildfires could increase by 50-70% (medium confidence).
The graphic below, from the report’s SPM, illustrates the risks facing Earth’s species (a) and human health risk from extreme heat-humidity (b) under different levels of global warming.
It shows that, at temperatures above 2C, some regions will see all of their wildlife exposed to dangerous temperatures, assuming the species do not relocate to somewhere else.
It also shows that, above 2C, some people will live in regions where temperature and humidity conditions are deadly every day of the year.
The risks identified in this report are larger at lower levels at warming, when compared to the IPCC’s last assessment in 2014.
This is because of new evidence from climate extremes already recorded, improved scientific understanding, new knowledge on how some humans and species are more vulnerable than others and a better grasp of the limits to adaptation, the report says with high confidence.
Because of “unavoidable” sea level rise, risks for coastal ecosystems, people and infrastructure will continue to increase beyond 2100, it adds with high confidence.
As climate change worsens, risks “will become increasingly complex and more difficult to manage”, the report says.
Climate change is likely to compound other societal issues, it says. For example, food shortages driven by warming are projected to interact with other factors, such as conflicts, pandemics and competition over land, the report says with high confidence.
Most pathways for how the world can meet its ambitious 1.5C temperature involve a period of “overshoot” where temperatures exceed this level of warming temporarily before dropping back down.
During this period of overshoot, the world would see “adverse impacts” that may worsen climate change, such as increased wildfires, mass mortality of ecosystems and permafrost thawing, the report says with medium confidence.
The report adds that solar geoengineering – methods for reflecting away sunlight to reduce temperature rise – has the “potential to offset warming within one or two decades and ameliorate some climate hazards”, but could also “introduce a widespread range of new risks to people and ecosystems” and “would not restore climate to a previous state”.
6. What are the risks of abrupt and irreversible change?
The report warns that continued emissions of GHGs will “further affect all major climate system components and many changes will be irreversible on centennial to millennial timescales”.
While “many changes in the climate system” will become larger “in direct relation to increasing global warming”, the likelihood of “abrupt and/or irreversible outcomes increases with higher global warming levels”, the report says with high confidence. For example, it says:
“As warming levels increase, so do the risks of species extinction or irreversible loss of biodiversity in ecosystems such as forests (medium confidence), coral reefs (very high confidence) and in Arctic regions (high confidence).”
The impacts of warming on some ecosystems are already “approaching irreversibility”, the report says, “such as the impacts of hydrological changes resulting from the retreat of glaciers, or the changes in some mountain (medium confidence) and Arctic ecosystems driven by permafrost thaw (high confidence)”.
Abrupt and irreversible changes can include those “triggered when tipping points are reached”, the report says:
The report has high confidence that “the probability of low-likelihood outcomes associated with potentially very large impacts increases with higher global warming levels”. The impact of these abrupt changes would be dramatic.
“[AMOC] is very likely to weaken over the 21st century for all considered scenarios (high confidence), however an abrupt collapse is not expected before 2100 (medium confidence). If such a low probability event were to occur, it would very likely cause abrupt shifts in regional weather patterns and water cycle, such as a southward shift in the tropical rain belt, and large impacts on ecosystems and human activities.”
For comparison, the AR5 synthesis report also concluded that a weakening of AMOC was very likely, but said that an abrupt transition or collapse in the 21st century was very unlikely.
The report notes that “low-likelihood, high-impact outcomes could occur at regional scales even for global warming within the very likely assessed range for a given GHG emissions scenario”.
The report has a particularly stark assessment on the projected impacts of global warming on the ocean. The authors warn, with high confidence, that sea level rise is “unavoidable for centuries to millennia due to continuing deep ocean warming and ice sheet melt”. And levels will “remain elevated for thousands of years”.
While the authors are virtually certain that sea level rise will continue through this century, “the magnitude, the rate, the timing of threshold exceedances, and the long-term commitment of sea level rise depend on emissions, with higher emissions leading to greater and faster rates of sea level rise”.
Over the next 2,000 years, global average sea level “will rise by about 2-3 metres if warming is limited to 1.5C and 2-6 m if limited to 2C”, the report says, with low confidence.
Warming beyond 2C could put the Earth’s massive ice sheets at risk, the report says:
“At sustained warming levels between 2C and 3C, the Greenland and West Antarctic ice sheets will be lost almost completely and irreversibly over multiple millennia (limited evidence).”
These projections of sea level rise across thousands of years are “consistent with reconstructed levels during past warm climate periods”, the report notes.
For example, it says with medium confidence, “global mean sea level was very likely 5-25 metres higher than today roughly 3m years ago, when global temperatures were 2.5-4C higher than 1850-1900”.
In addition to rising sea levels, the authors say it is virtually certain that ocean acidification – where seawater becomes less alkaline – will continue throughout this century. And they have high confidence that deoxygenation – the decline in oxygen levels in the ocean – will too.
The report also cautions that the amount of warming – and the impact it would have – could be more severe than projected.
For example, it says, “warming substantially above the assessed very likely range for a given scenario cannot be ruled out, and there is high confidence this would lead to regional changes greater than assessed in many aspects of the climate system”.
On sea levels, the authors add:
“Global mean sea level rise above the likely range – approaching two metres by 2100 and in excess of 15 metres by 2300 under a very high GHG emissions scenario (SSP5-8.5) (low confidence) – cannot be ruled out due to deep uncertainty in ice-sheet processes and would have severe impacts on populations in low elevation coastal zones.”
It acknowledges that there has been an “improved understanding” of what constitutes economic and non-economic losses and damages. In turn, this has served to inform climate policy as well as highlight governance, financial and institutional gaps in how it is being addressed.
After this single mention, the report discusses “losses and damages” more broadly. These, it defines in a footnote in the SPM, are the “adverse observed impacts and/or projected risks and can be economic and/or non-economic”.
Including loss and damage in the IPCC’s assessments has been a fraught process. The use of two separate terms separates the scientific “losses and damages” from the political debate of “loss and damage” under the UNFCCC, even as impacted countries hope to connect the two.
In the plenary discussions, Grenada – supported by Senegal, Antigua and Barbuda, Timor Leste, Kenya and Tanzania – wanted vulnerable countries to be referenced and the differences between the two terms explicitly clarified, given that “the distinction is often confusing to people outside of the IPCC”. The US, meanwhile, supported putting a definition in the footnote.
On the impacts of climate change, the report recognises and reviews “strengthened” evidence of heatwaves, extreme rainfall, droughts and tropical cyclones, plus their attribution to human influence, since the last synthesis report.
In all regions, extreme heat events have resulted in human mortality and morbidity, it says with very high confidence, while climate-related food-borne and water-borne diseases have increased. Climate change is also contributing to humanitarian crises “where climate hazards interact with high vulnerability”, the report states with high confidence.
Climate change has caused “substantial damages, and increasingly irreversible losses” in land-based, freshwater, coastal, ocean and open ecosystems, as well as in glaciers and continental ice sheets, the report’s summary says with high confidence.
The widespread “losses and damages to nature and people” are unequally distributed across systems, regions and sectors”, says the report’s summary, pointing to both economic and non-economic losses.
Sectors such as agriculture, forestry, fishery, energy, and tourism that are “climate exposed” have experienced economic damages from climate change, the report states with high confidence.
Across the world, non-economic loss and damage impacts, such as mental health challenges, were associated with trauma from extreme weather events and loss of livelihoods and culture. (According to the Earth Negotiations Bulletin, India requested that mental health not be included in these impacts, which Finland opposed.)
The report says with high confidence that “vulnerable communities who have historically contributed the least to current climate change are disproportionately affected”.
For example, fatalities from floods, droughts and storms were 15 times higher in highly vulnerable regions between 2010 to 2020, compared to regions with very low vulnerability, it states with high confidence.
In urban areas, losses and damages are “concentrated” in communities of economically and socially marginalised residents, the report notes.
The figure below shows observed impacts on human systems and ecosystems attributed to climate change at global and regional levels, along with confidence in their attribution to climate change.
The report states with very high confidence that “losses and damages escalate with every increment of global warming”.
These will be higher at 1.5C and even higher at 2C, the report’s summary states. Compared to AR5, “global aggregated risk levels” will be high to very high even at lower warming levels, owing to an improved understanding of exposure, vulnerability and recent evidence, including “limits to adaptation”. Climatic and non-climatic risks will increasingly interact, leading to “compound and cascading risks” that are difficult to manage.
However, near-term climate actions that rein in global warming to “close to 1.5C” could “substantially reduce” losses and damages to humans and ecosystems. Still, even these actions “cannot eliminate them all”, the report notes.
Overall, the magnitude and rate of future losses and damages “depend strongly” on near-term mitigation and adaptation actions, the report says with very high confidence.
Delaying mitigation will only increase warming, which could derail the effectiveness of adaptation options, it says with high confidence, leading to more climate risks and related losses and damages.
However, the report and its summary warn with high confidence that “adaptation does not prevent all losses and damages”. The authors point out with high confidence that some ecosystems, sectors and regions have already hit limits to how much they can adapt to climate impacts. In some cases, adaptive actions are unfeasible – that is, they have “hard limits” – for certain natural systems or are simply not an option because of socioeconomic or technological barriers – known as “soft limits” – leading to unavoidable loss and damage impacts.
“One of the new messages in this report is that it effectively busts the myth of endless adaptation,” said report author Dr Aditi Mukherji, director at the Consultative Group on International Agricultural Research (CGIAR), speaking at a press conference.
8. Why is climate action currently ‘falling short’?
Current pledges for how countries will cut emissions by 2030 make it likely that global warming will exceed 1.5C this century and will make it harder to limit temperatures to 2C, according to one of the headline findings of the report.
The establishment of the Paris Agreement – the landmark climate deal reached in 2015 – has led to more target-setting and “enhanced transparency” for climate action, the report says with medium confidence.
At the same time, there has been “rising public awareness” about climate change and an “increasing diversity” of people taking action. These efforts “have overall helped accelerate political commitment and global efforts to address climate change”, the report says, adding:
“In some instances, public discourses of media and organised counter movements have impeded climate action, exacerbating helplessness and disinformation and fuelling polarisation, with negative implications for climate action (medium confidence).”
It says with high confidence that many rules and economic tools for tackling emissions have been “deployed successfully” – leading to enhanced energy efficiency, less deforestation and more low-carbon technologies in many countries. This has in some cases lowered emissions.
By 2020, laws for reducing emissions were in place in 56 countries – covering 53% of global emissions, the report says.
At least 18 countries have seen their production and consumption emissions fall for at least 10 years, it adds. But these reductions have “only partly offset” global emissions increases.
The report adds that there are several options for tackling climate change that are “technically viable”, “increasingly cost effective” and are “generally supported by the public”.
It adds that, over 2010-19, there have been large decreases in the unit costs of solar power (85%), wind (55%) and lithium ion batteries (85%). In many regions, electricity from solar and wind is now cheaper than that derived from fossil fuels, the report says.
(According to the Earth Negotiations Bulletin, a group of countries including Germany, Denmark and Norway strongly argued for the report to highlight that renewables are now cheaper than fossil fuels in many regions. Finland suggested adding that fossil fuels are the “root cause” of climate change, but this was strongly opposed by Saudi Arabia.)
At the same time, there have been “large increases in their deployment”, including a global average of 10 times for solar and 100 times for electric cars, the report says.
Falling costs and increased deployment have been boosted by public research and funding and demand-side policies such as subsidies, it says, adding:
“Maintaining emission-intensive systems may, in some regions and sectors, be more expensive than transitioning to low-emission systems (high confidence).”
(According to the Earth Negotiations Bulletin, India, supported by Brazil, said the sentence “favoured developed countries as it did not reference feasibility and challenges”.)
Despite this, a “substantial emissions gap” remains between what global GHG emissions are projected to be in 2030 and what they must be if the world is to limit global warming to 1.5C or 2C, the report says with high confidence. (The 2030 projections are derived from country climate pledges made prior to COP26 in 2021.)
This gap would “make it likely that warming will exceed 1.5C during the 21st century”, the report says with high confidence.
Pathways for how the world can limit global warming to 1.5C or 2C depend on deep global emissions cuts this decade, it adds with high confidence.
The report says with medium confidence that country climate plans ahead of COP26 would lead to around 2.8C of warming (range from 2.1-3.4C) by 2100.
However, it adds with high confidence that policies put in place by countries by the end of 2020 would not be sufficient to achieve these climate plans. This represents an “implementation gap”.
When just policies put in place by the end of 2020 are considered, around 3.2C of warming (range 2.2-3.5C) is projected by 2100, the report says with medium confidence.
The chart below, from the SPM, illustrates the warming expected in 2100 from policies implemented by 2020 (red), as well as what emissions cuts would need to look like to reach 1.5C (blue) or 2C (green).
“Additional implemented policies since the cut-off date would lead to those curves drawing down a little bit, compared to where they are. But everything that has happened since the IPCC cut-off – which is outside the scope of this synthesis report – would suggest that we’re still some way off.”
(A November 2022 assessment from the independent research group Climate Action Tracker found that country climate plans for 2030 in place by that time would cause 2.4C (range 1.9-2.9C) of warming. Policies in place by that time would cause 2.7C (range 2.2-3.4C), it added.)
The report also notes that many countries have signalled intentions to achieve net-zero greenhouse gas or CO2 emissions by 2050. However, it says such pledges differ “in terms of scope and specificity, and limited policies are to date in place to deliver on them”.
In most developing countries, the rollout of low-carbon technologies is lagging behind, the report adds. This is due in part to a lack of finance and technology transfer from developed countries, it says with medium confidence.
The leveraging of climate finance for developing countries has slowed since 2018, the report says with high confidence. It adds:
“Public and private finance flows for fossil fuels are still greater than those for climate adaptation and mitigation (high confidence).”
9. What is needed to stop climate change?
“There is a brief and rapidly closing window of opportunity to secure a liveable and sustainable future for all,” the report says with high confidence.
The synthesis delivers a blunt message on what will be needed to stop climate change, saying “limiting human-caused warming requires net-zero CO2 emissions”.
(The Earth Negotiations Bulletin says there was debate over this opening sentence in section B5 of the SPM. It reports: “The authors said that a fundamental insight of AR6 is that, to hold warming at any level, net-zero [CO2] emissions are required at some point.)
The report goes on to say, with high confidence, that reaching net-zero greenhouse gas emissions would imply net-negative CO2 – and would “result in a gradual decline in surface temperatures”.
Reaching net-zero emissions requires “rapid and deep and, in most cases, immediate greenhouse gas emissions reductions in all sectors this decade”, according to the report.
Repeating language from the underlying WG3 report, it adds that global GHG emissions must peak “between 2020 and at the latest before 2025” to keep warming below 1.5C or 2C.
In contrast with the direct wording on net-zero, the report barely mentions coal, oil and gas.
However, it does say net-zero would mean a “substantial reduction in overall fossil fuel use”.
Staying below 1.5C or 2C depends on cumulative carbon emissions at the time of reaching net-zero CO2 and the level of greenhouse gas emissions cuts this decade, the report says.
Specifically, net-zero CO2 needs to be reached “in the early 2050s” to stay below 1.5C:
“Pathways that limit warming to 1.5C (>50%) with no or limited overshoot reach net-zero CO2 in the early 2050s, followed by net-negative CO2 emissions. Those pathways that reach net-zero GHG emissions do so around the 2070s. Pathways that limit warming to 2C (>67%) reach net-zero CO2 emissions in the early 2070s.”
(There was some confusion on this point after a speech by UN secretary-general António Guterres launching the IPCC report. Guterres called for global net-zero emissions by 2050, with developed countries going faster, but did not say if he was referring to CO2 or GHGs.)
There is a direct link between cumulative carbon emissions and warming, with the report saying that every 1,000GtCO2 raises temperatures by 0.45C. The report says with high confidence:
“From a physical science perspective, limiting human-caused global warming to a specific level requires limiting cumulative CO2 emissions, reaching at least net-zero CO2 emissions, along with strong reductions in other greenhouse gas emissions.”
This results in “carbon budgets” that must not be exceeded if the world is to limit warming to a given level. As of the start of 2020, the remaining budget to give a 50% chance of staying below 1.5C is 500GtCO2, rising to 1,150GtCO2 for a 67% chance of staying below 2C.
(Stronger reductions of non-CO2 emissions would mean a larger carbon budget for a given temperature limit, the report notes, and vice versa.)
Some four-fifths of the total budget for 1.5C has already been used up during 1850-2019 and the last fifth would be “almost exhaust[ed]” by 2030, if emissions remained at 2019 levels.
In order to stay within the budget for 1.5C, global greenhouse gas emissions would need to fall to 43% below 2019 levels by 2030 and to 60% below by 2035, falling 84% by 2050.
Even faster reductions are required for CO2 emissions, which would fall to 48% below 2019 levels by 2030, 65% by 2035 and 99% by 2050, when they would effectively hit net-zero.
The synthesis report lists these numbers in a new table, below. While the information is not new, it had not previously been presented in an accessible format. It was added during the week-long approval process and is labelled “Table XX”.
At a briefing for journalists held by the UK Science Media Centre, Dr Chris Jones, synthesis report author and research fellow at the UK’s Met Office, said: “We hope, obviously, this information is useful for the stocktake process.”
(This refers to the “global stocktake” of progress to date and the efforts needed to meet international climate goals, which is taking place this year as part of the UN climate process.)
The report outlines how the world could reach net-zero CO2 emissions via a “substantial reduction in overall fossil fuel use, minimal use of unabated fossil fuels, and use of carbon capture and storage (CCS) in the remaining fossil fuel systems”.
(The phrase “unabated fossil fuels” is defined in a footnote to the report, by comparison with “abatement”, which it says would mean “capturing 90% or more CO2 from power plants, or 50–80% of fugitive methane emissions from energy supply”.)
While the world needs to make “deep and rapid” cuts in gross emissions, the use of CO2 removal (CDR) is also “unavoidable” to reach net-zero, the report says with high confidence.
The report explains:
“[P]athways reaching net-zero CO2 and GHG emissions include transitioning from fossil fuels without carbon capture and storage (CCS) to very low- or zero-carbon energy sources, such as renewables or fossil fuels with CCS, demand-side measures and improving efficiency, reducing non-CO2 GHG emissions, and CDR.”
CDR will be needed to “counterbalance” hard-to-abate residual emissions in some sectors, for example “some emissions from agriculture, aviation, shipping and industrial processes”.
Emphasising the challenge of limiting warming, the report says the fossil fuel infrastructure that has already been built would be enough to breach the 1.5C carbon budget, if operated in line with historical patterns and in the absence of extra abatement.
This is shown in the figure below. The top panel shows historical emissions and the remaining budgets for 1.5C or 2C, as well as emissions this decade if they remain at 2019 levels and the emissions of existing and planned fossil fuel infrastructure.
The lower panel shows historical warming and potential increases by 2050, in relation to the carbon budgets and the range of possible emissions over the same period.
Delaying emissions cuts risks “lock-in [of] high-emissions infrastructure”, the report states, adding with high confidence that this would “raise risks of stranded assets and cost-escalation, reduce feasibility, and increase losses and damages”.
The report notes that only “a small number of the most ambitious global modelled pathways” avoid temporary overshoot of the 1.5C target. However, warming “could gradually be reduced again by achieving and sustaining net-negative global CO2 emissions”.
On the other hand, the IPCC warns of “additional risks” as a result of overshoot, defined as exceeding a warming level and returning below it later. It states with high confidence:
“Overshoot entails adverse impacts, some irreversible, and additional risks for human and natural systems, all growing with the magnitude and duration of overshoot.”
The report adds that some of these impacts could make it harder to return warming to lower levels, stating with medium confidence:
“Adverse impacts that occur during this period of overshoot and cause additional warming via feedback mechanisms, such as increased wildfires, mass mortality of trees, drying of peatlands, and permafrost thawing, weakening natural land carbon sinks and increasing releases of GHGs would make the return more challenging.”
It says the risks around overshoot, as well as the “feasibility and sustainability concerns” for CDR, can be minimised by faster action to cut emissions. Similarly, development pathways that use resources more efficiently also minimise dependence on CDR.
10. How can individual sectors scale up climate action?
In order to limit warming to 2C or below by the end of the century, all sectors must undergo “rapid and deep, and in most cases, immediate greenhouse gas emissions reductions”, the report says.
Limiting warming to 1.5C with “no or limited overshoot” requires achieving net-zero CO2 emissions in the early 2050s. To keep warming to 2C, net-zero CO2 must be achieved “around the early 2070s”.
It continues, with medium confidence:
Reducing emissions from the energy sector requires a combination of actions, the report says: a “substantial reduction” in the use of fossil fuels; increased deployment of energy sources with zero or low emissions, “such as renewables or fossil fuels with CO2 capture and storage” (CCS); improving energy efficiency and conservation; and “switching to alternative energy carriers”.
For sectors that are harder to decarbonise, such as shipping, aviation, industrial processes and some agriculture-related emissions, the report notes that using carbon dioxide removal (CDR) technologies to counterbalance these residual emissions “is unavoidable”.
The language around CCS and CDR was some of the most contentious during the approval session. According to the Earth Negotiations Bulletin, Germany “suggested including a brief overview of the feasibility and current deployment of different CDR methods”, with France adding that policymakers must be made aware of the associated challenges.
But Saudi Arabia countered that if these barriers were made explicit in this section, it “would require similar balancing language on the feasibility of solar and renewables elsewhere in the report”.
Similar discussions were had around CCS, with the authors ultimately agreeing to add a sub-paragraph in a footnote that details both the limits and benefits of CCS, at the urging of Germany and Saudi Arabia, respectively.
The report discusses several technologies across a range of maturity, removal and storage potential and costs. It finds that “all assessed modelled pathways that limit warming to 2C (>67%) or lower by 2100” rely, at least in part, on mitigation from agriculture, forestry and other land use (AFOLU). Such approaches are currently “the only widely practised CDR methods”, the report notes.
However, it details trade-offs and barriers to large-scale implementation of AFOLU-based mitigation, including climate change impacts, competing demands for land use, endangering food security and violation of Indigenous rights.
The report also discusses sector-specific actions that can be taken in order to limit emissions and climate impacts. These transformations, it says, are “required for high levels of human health and well-being, economic and social resilience, ecosystem health and planetary health”.
The chart below shows near-term feasibility of adaptation (left) and mitigation (right) options, divided across six sectors (top left to bottom right): energy supply; land, water and food; settlements and infrastructure; health; society, livelihood and economy; and industry and waste.
For adaptation options, the figure shows the potential for synergies with mitigation strategies and the feasibility of these options up to 1.5C of warming, from low (light purple) to high (dark blue). The dots in each box represent the confidence level, from low (one dot) to high (three dots).
On the right, mitigation options are presented with their potential contribution to emissions reductions by 2030, in GtCO2e per year. The colours indicate the cost of each option, from low (yellow) to high (red), with blue indicating options that are cheaper than fossil fuels. Some of the mitigation options with the highest potential for cost-saving are solar and wind power, efficient vehicles, lighting and other equipment, and public transit and cycling.
Some of these mitigation options relate to changes in energy demand, rather than supply. This includes “changes in infrastructure use, end-use technology adoption and socio-cultural and behavioural change”, the report says, noting that such changes can reduce emissions in end-use sectors by 40-70% by mid-century.
The chart below shows the mid-century mitigation potential of demand-side changes across a range of sectors: food (including diet and waste), land transport, buildings, industry and electricity. The green arrows represent the mitigation potential in GtCO2 per year.
Section 4.5 of the report goes into detail about near-term mitigation and adaptation, in subsections covering energy systems; industry; cities, settlements and infrastructure; land, ocean, food and water; health and nutrition; and society, livelihoods and economies. At the urging of India (supported by Saudi Arabia and China) in the approval session, the report notes that the availability and feasibility of these options differs “across systems and regions”.
On energy systems, the report says with high confidence that “major energy system transitions” are required and with very high confidence that adaptation “can help reduce climate-related risks to the energy system”, including extreme events that can damage or otherwise affect energy infrastructure.
It notes that many of the options for large-scale emissions reductions are “technically viable and supported by the public”. It adds:
“Maintaining emission-intensive systems may, in some regions and sectors, be more expensive than transitioning to low emission systems.”
However, adaptation measures for certain types of power generation, such as hydropower, have “decreasing effectiveness at higher levels of warming” beyond 1.5C or 2C, the report notes. Reducing vulnerabilities in the energy sector requires diversification and changes on the demand side, including improving energy efficiency.
The strategies to reduce industrial emissions “differ by type of industry”, the report says. Light manufacturing can be “largely decarbonised” through available technologies and electrification, while decarbonising others will require the use of carbon capture and storage and the development of new technologies. The report adds that extreme events will cause “supply and operational disruptions” across many industries.
“Effective mitigation” strategies can be implemented at every step of building design, construction and use, the report says. It notes that demand-side measures can help reduce transportation-related emissions, as can re-allocating street space for pedestrians and cyclists and enabling telework.
With high confidence, it says:
“Key infrastructure systems including sanitation, water, health, transport, communications and energy will be increasingly vulnerable if design standards do not account for changing climate conditions.”
The report also says that “green” and “blue” infrastructure have myriad benefits: climate change mitigation, reducing extreme weather risk and improving human health and livelihoods.
AFOLU, as well as the ocean, offer “substantial mitigation and adaptation potential…that could be upscaled in the near term across most regions”, the report finds. It notes that conservation and restoration of ecosystems provide “the largest share” of this potential. It reads:
Such actions must be taken with the cooperation and involvement of local communities and Indigenous peoples, the report adds.
With very high confidence, the report states that “mainstream[ing]” health considerations into policies will benefit human health. There is also high confidence in the existing availability of “effective adaptation options” in the health sector, such as improving access to drinking water and vaccine development. The report states with high confidence:
“A key pathway to climate resilience in the health sector is universal access to healthcare.”
The report calls for improving climate education, writing with high confidence:
“Climate literacy and information provided through climate services and community approaches, including those that are informed by Indigenous knowledge and local knowledge, can accelerate behavioural changes and planning.”
It says that many types of adaptation options “have broad applicability across sectors and provide greater risk reduction benefits when combined”. It also calls for “accelerating commitment and follow-through” from private sector actors.
11. What does the report say about adaptation?
The world is not adapting fast enough to climate change – and limits to adaptation have already been reached in some regions and ecosystems, the report says.
It says with very high confidence that there has been progress with adaptation planning and roll-out in all sectors and regions – and that accelerated adaptation will bring benefits for human wellbeing.
Adaptation to water-related risks make up more than 60% of all documented adaptation practices, the report says with high confidence.
Examples of effective adaptation have occurred in food production, such as through planting trees on cropland, diversification in agriculture and water management and storages, the report says with high confidence.
“Ecosystem-based approaches”, such as urban greening and restoring wetlands and forests, have been effective in “reducing flood risks and urban heat”, it adds with high confidence.
In addition, combinations of “non-structural measures”, such as early warning systems, and structural measures such as levees have reduced deaths from flooding, the report says with medium confidence.
But, despite progress, most adaptation is “fragmented, incremental, sector-specific and unequally-distributed across regions”, the report says, adding:
“Adaptation gaps exist across sectors and regions, and will continue to grow under current levels of implementation, with the largest adaptation gaps among lower income groups.”
Key barriers to adaptation include a lack of financial resources, political commitment and a “low sense of urgency”, the report says.
The total amount spent on adaptation has increased since 2014. However, there is currently a widening gap between the costs of adaptation and the amount of money set aside for adaptation, according to the report.
It says with very high confidence that the “overwhelming majority” of climate finance goes towards mitigation rather than adaptation. (See: Why is finance an ‘enabler’ and ‘barrier’ for climate action?)
It adds with medium confidence that financial losses caused by climate change can reduce funds available for adaptation – hence, leaving countries more vulnerable to future impacts. This is particularly true for developing and least-developed countries.
The report says with medium confidence that some people are already experiencing “soft limits” to adaptation. “Soft limits” are those where there is currently no way to adapt to the change, but there may be a way in the future. This includes small-scale farmers and households living in low-lying coastal areas.
Some areas have reached “hard limits” to adaptation, where no further adaptation to climate change is possible, the report says with high confidence. This includes some rainforests, tropical coral reefs, coastal wetlands, and polar and mountain ecosystems.
In the future, “adaptation options that are feasible and effective today will become constrained and less effective with increasing global warming”, the report says. It adds:
“With increasing global warming, losses and damages will increase and additional human and natural systems will reach adaptation limits.”
For example, the effectiveness of reducing climate risks by switching crop varieties or planting patterns – commonplace on farms today – is projected to decrease above 1.5C of warming, the report says with high confidence. The effectiveness of on-farm irrigation is projected to decline above 3C, it adds.
Above 1.5C of warming, small island populations and regions dependent on glaciers for freshwater could face hard adaptation limits, the report says with medium confidence.
At this level of warming, ecosystems such as coral reefs, rainforests and polar and mountain ecosystems will have surpassed hard adaptation limits – meaning some ecosystem-based approaches will become ineffective, the report says with high confidence.
By 2C, soft limits are projected for multiple staple crops, particularly in tropical regions, it says with high confidence. By 3C, hard limits are projected for water management in parts of Europe, it says with medium confidence.
(According to the Earth Negotiations Bulletin, China requested removing a reference to “adaptation limits” from one of the headline statements of the SPM. It was opposed by countries including the UK, Denmark, Germany, Saint Kitts and Nevis, the Netherlands, Switzerland, Mexico and Belize.)
The report says with high confidence that sea level rise poses a “distinct and severe adaptation challenge”. This is because it requires dealing with both slow onset changes and increases in extreme sea level events such as storm surges and flooding.
The graphic below illustrates some of the adaptation responses to sea level rise, including the time it takes for implementation and their typical intended lifetimes.
“Ecosystem-based” approaches include enhancing coastal wetlands. Such approaches come with co-benefits for biodiversity and reducing emissions, but start to become ineffective above 1.5C of warming, the report says with medium confidence.
“Sediment-based” approaches include seawalls. These can be ineffective “as they effectively reduce impacts in the short-term but can also result in lock-ins and increase exposure to climate risks in the long-term”, the report says.
Planned relocation methods can be more effective if they are aligned with sociocultural values and involve local communities, the report says.
The report warns with high confidence that there is now more evidence of “maladaptation” – actions intended to adapt to climate change that create more risk and vulnerability.
Examples of maladaptation include new urban buildings that cannot easily be adjusted for climate risks or high-cost irrigation systems for agriculture in areas where droughts are projected to intensify, the report says.
Maladaptation “especially affects” marginalised and vulnerable groups, including Indigenous peoples, ethnic minorities, low-income households and people living in informal settlements. This can “reinforce and entrench” existing inequalities.
12. What are the benefits of near-term climate action?
The report is clear that fast action to mitigate emissions and adapt to climate impacts has a range of benefits – but acknowledges that it will likely be disruptive and have high up-front costs.
The rate of climate change and the associated risks “depend strongly” on near-term climate action, the report says. The SPM notes with high confidence:
“The choices and actions implemented in this decade will have impacts now and for thousands of years.”
The overarching benefit of near-term mitigation action is less global warming over time and thereby fewer negative impacts, such as extreme weather events.
Accelerated mitigation measures would also reduce future adaptation costs alongside other benefits, such as reducing the risk of irreversible climate changes, the synthesis report says.
A quick reduction in methane emissions, in particular, can limit near-term warming, the report says with high confidence. Methane has a much shorter lifespan in the atmosphere than CO2.
Delaying actions to prevent further warming will lead to a larger temperature rise, which will, in turn, make adaptation measures less effective, it says.
Adaptation actions can take a long time to be put in place. The report stresses that long-term planning and faster implementation, especially in this decade, “is important to close adaptation gaps”.
Adaptation measures, the report adds, can improve agricultural productivity, innovation, health and wellbeing, food security, livelihood and biodiversity conservation.
There are other co-benefits to cutting emissions and taking faster action on adaptation. The SPM says that “deep, rapid and sustained” action in this decade would lower air pollution, spark more walking and cycling and prompt more sustainable, healthy diets.
The money saved from a health perspective as a result of improved air quality “can be of the same order of magnitude as mitigation costs, and potentially even larger”, the report adds.
There are further economic benefits to near-term climate action, but the SPM says the cost-benefit analysis “remains limited” in assessing all avoided damages.
Outside of the benefits of avoiding possible damages, the economic and social benefits of limiting global warming to 2C exceeds mitigation costs in most literature, the SPM says with medium confidence.
The SPM says that faster mitigation with emissions peaking earlier increases the co-benefits of action and reduces risks and costs in the long-term.
It further says, with high confidence, that near-term actions require “high up-front investments and potentially disruptive changes”.
Barriers to deploy mitigation and adaptation actions need to be removed or reduced to utilise these options at scale, the report says.
To scale up these actions, the report says that both low- and high-cost options, such as using more renewables, making buildings more efficient and using electric vehicles, are required to avoid future lock-ins, advance innovation and start transformational changes.
The impacts of these changes can be “moderated” by reforms and policies in order to accelerate climate action such as improving access to finance for low-emissions infrastructure and technologies, especially in developing countries.
Delaying action comes with multiple challenges, the report says, such as cost escalation risks, lock-in of infrastructure and stranded assets.
In other words, continuing to install unabated fossil fuel infrastructure will “lock-in” emissions into the future. And taking action on fossil-fuel burning sooner rather than later would limit the size of stranded assets – such as fossil-fuel infrastructure – that will be worth a lot less money in future in a world more reliant on low-carbon energy.
Delaying action on this would increase policy risks and may endanger efforts to limit global warming, the report says with high confidence.
Climate action is enabled by good climate governance providing an overall direction, the report says.
This involves setting targets, including climate action in different policy areas, prioritising equitable decision-making and enhancing access to finance. The report adds that climate action benefits from drawing on a diverse range of knowledge.
13. Why is finance an ‘enabler’ and ‘barrier’ for climate action?
Finance is one of the “critical enablers” to speed up climate action, the synthesis report outlines, and lack of funding is a barrier to progress.
Difficulty accessing climate finance slows down both mitigation and adaptation action, particularly in developing countries, the report warns. Improving access to funds will help to accelerate climate action, the report says with very high confidence.
It adds that funding for mitigation and adaptation needs to increase “many-fold” to achieve climate goals, address risks and speed up investment in emissions reductions.
Global climate finance flows have increased and financing channels have broadened over the past decade, but the report notes that average growth has slowed since 2018. The report adds with high confidence:
“Public and private finance flows for fossil fuels are still greater than those for climate adaptation and mitigation.”
It assesses that climate funding is “uneven” and has “developed heterogeneously across regions and sectors”, adding that the money falls short of what is needed to slash emissions and adapt to climate impacts.
There is enough global capital to close investment gaps, the report says, but “barriers” are preventing this funding being used instead for climate action.
Closing gaps and improving access to finance, alongside other actions, can “act as a catalyst for accelerating” climate action, the SPM says. The report builds on this, saying:
“Accelerated support from developed countries and multilateral institutions is a critical enabler to enhance mitigation and adaptation action and can address inequities in finance, including its costs, terms and conditions, and economic vulnerability to climate change.”
Many developing countries do not have enough financial resources for adaptation to help reduce associated economic and non-economic losses and damages, the report says.
The SPM outlines with high confidence that increasing access to finance can help tackle “soft”, avoidable adaptation limits and avert some of the rising risks of climate change. (See: What does the report say about adaptation?)
The “overwhelming majority” of climate finance is geared towards mitigation. But this still falls short, the SPM says, adding with medium confidence:
“Average annual modelled mitigation investment requirements for 2020 to 2030 in scenarios that limit warming to 2C or 1.5C are a factor of three to six greater than current levels, and total mitigation investments (public, private, domestic and international) would need to increase across all sectors and regions.”
Limited access to funding is listed as one of the key barriers to a number of actions including the adoption of low-emissions technology in developing countries.
Harmful impacts of climate change can further reduce a nation’s climate financial resources by causing losses and damages and also impeding economic growth. This adds to the financial constraints for adaptation, especially in developing and least developed countries.
The largest climate finance gaps and opportunities exist in developing countries, the report says, adding that more support is needed from developed nations and multilateral institutions to address inequities.
This could come in the form of larger public grants for climate funding “for vulnerable regions, e.g., in sub-Saharan Africa,” the report says. It adds that these would be cost-effective and have high social returns in terms of access to basic energy.
Reducing the barriers standing in the way of committing more money to climate action would require “clear signalling and support by governments” through actions such as decreasing the perceived risks of climate investments and increasing the returns, the SPM says.
Central banks, investors and other financial actors can change the “systemic underpricing of climate-related risks” and also reduce the “widening disparities” between the money available and the amount required, the SPM adds, noting:
“Public finance is an important enabler of adaptation and mitigation, and can also leverage private finance.”
Developed countries pledged to provide $100bn in climate funding each year by 2020 to help developing countries deal with climate change. The SPM notes that, as of 2018, finance levels were below this goal. (In 2021, Carbon Brief analysed why climate finance flows are falling short.)
According to the Earth Negotiations Bulletin, India, supported by Saudi Arabia and Brazil, requested a reference to this goal in a section on the adoption of low-emission technologies to highlight the finance gap for developing countries.
The final report does reference the missed pledge elsewhere, but the text of low-emission technologies instead refers more broadly to the constraints of “limited finance”.
The SPM says that climate-resilient development – prioritising climate in all aspects of decision-making and policies – is aided by more international cooperation to improve access to finance and better align climate finance flows with the money required.
The report says faster global financial cooperation is key to aiding low-emission and just transitions. (A just transition is one in which workers and their communities are supported in the shift to a low-carbon economy, which is central to the idea of climate justice.) It can also address inequities in access to finance.
In order to scale-up financial flows, the report says there must be lower regulatory market barriers, a stronger alignment of public finance and more public funding in an effort to reduce the perceived risks of low-emission investments.
14. What are the co-benefits for the Sustainable Development Goals?
Comprising 17 goals, this “shared blueprint” for people and the planet recognises that ending poverty “and other deprivations” must accompany strategies that improve health, education, reduce inequality while combating climate change and protecting oceans and forests.
The synthesis report lays out how climate adaptation and mitigation actions can translate into co-benefits that aid countries’ efforts to meet their SDGs.
According to the report, both sets of actions have more potential synergies than potential trade-offs with the SDGs. This, however, depends on the scale and context of how mitigation and adaptation measures are implemented, the interactions between and within different sectors involved, cooperation between countries, governance, policy design and how these options are timed, sequenced and stringently deployed.
Ending “extreme poverty, energy poverty and providing decent living standards to all, consistent with sustainable development objectives…can be achieved without significant global emissions growth”, the report states with high confidence.
The report’s summary recognises that countries are at different levels of development, seeking to improve the well-being of people. With high confidence, it states:
“Development priorities among countries also reflect different starting points and contexts, and enabling conditions for shifting development pathways towards increased sustainability will therefore differ, giving rise to different needs.”
Nonetheless, many mitigation and adaptation systems can help countries meet their near-term development goals in energy, urban and land systems, the report says with high confidence.
For instance, better air quality and improved health are some of the many co-benefits of deploying low-carbon energy systems, while urban mass transit powered by these systems can contribute to health, employment, energy security and “deliver equity”.
Conserving, protecting and restoring ecosystems, while managing them to help communities adapt to climate impacts, can help regions attain their food security and biodiversity conservation goals, the report says with high confidence.
In countries and regions that are highly dependent on fossil fuels – not just for energy, but revenues and jobs – mitigating risk calls for “just transition principles, processes and practices” and policies that promote economic and energy diversification, the SPM says with high confidence.
Mitigation actions that are embedded within a wider development context can, therefore, make for faster, deeper and wider emissions reductions, it states with medium confidence.
But to design “context-relevant” actions and plan for their implementation “requires considering people’s needs, biodiversity, and other sustainable development dimensions”, the report states with very high confidence.
Importantly, the report calls “effective governance” to limit potential trade-offs of some mitigation choices – such as the risks posed by large-scale afforestation and bioenergy projects to food systems, biodiversity, ecosystems and livelihoods, it says with high confidence.
Crucially, this requires “adequate institutional capacity at all levels” to safeguard against trade-offs.
Mitigation and adaptation actions taken together – accounting for trade-offs – can benefit not just human well-being, but deliver better ecosystem and planetary health, the report states with high confidence. Social safety nets and land restoration are examples that serve both adaptation and mitigation goals, with co-benefits for poverty reduction and food security.
However, there will be trade-offs, the report cautions. But these can be “evaluated and minimised” by giving weight to “capacity building, finance, technology transfer, governance, development, gender and social equity considerations with meaningful participation of local communities, Indigenous peoples and vulnerable populations”, it states with high confidence.
15. What does the report say about equity and inclusion?
“Equity remains a central element in the UN climate regime,” the SPM says. The report has a section dedicated to “equity and inclusion in climate change action”, which discusses how to ensure that those most vulnerable to the impacts of climate change can contribute to and benefit from climate mitigation and adaptation efforts.
The SPM says that “ambitious mitigation pathways imply large and sometimes disruptive changes in economic structure”. This can include a “shifting of income and employment” during the transition to low-emissions activities.
But the report has high confidence that “social safety nets” and “redistributive policies” that “shield the poor and vulnerable” can resolve trade-offs for a range of sustainable development goals, such as education, hunger, poverty, gender and energy access.
For example, it has high confidence that “while some jobs may be lost, low-emissions development can also open up opportunities to enhance skills and create jobs”. The report emphasises the importance of “broadening equitable access” to the relevant finance, technologies and governance.
“Equity, inclusion, just transitions, broad and meaningful participation of all relevant actors in decision making at all scales enable deeper societal ambitions for accelerated mitigation, and climate action more broadly, and build social trust, support transformative changes and an equitable sharing of benefits and burdens”.
The report says that between 3.3 and 3.6 billion people are living in “contexts that are highly vulnerable to climate change”, where vulnerability is highest in “locations with poverty, governance challenges and limited access to basic services and resources, violent conflict and high levels of climate-sensitive livelihoods”.
It says that adaptation can be used to moderate the risks of climate change and the authors have high confidence that “adaptation progress is unevenly distributed with observed adaptation gaps”. The report adds:
“Present development challenges causing high vulnerability are influenced by historical and ongoing patterns of inequity such as colonialism, especially for many Indigenous Peoples and local communities.”
To effectively address adaptation gaps and avoid maladaptation, the report says that “meaningful participation and inclusive planning, informed by cultural values, Indigenous knowledge, local knowledge, and scientific knowledge can help”.
The report also notes that different countries have their own priorities for development, which give rise to differing needs.
For example, it says that “in several countries just transition commissions, task forces and national policies have been established”, while in others, the principles of a just transition need to be integrated into policies through “collective and participatory decision-making processes”.
This section of the report also discusses behavioural interventions. It has high confidence that “individuals with high socioeconomic status contribute disproportionately to emissions, and have the highest potential for emissions reductions”. It says there are many options for reducing emissions from this group, which can be supported by policies, infrastructure, and technology.
Meanwhile, it has high confidence that, for lower-income groups, “eradicating extreme poverty, energy poverty, and providing decent living standards to all in these regions in the context of achieving sustainable development objectives, in the near-term, can be achieved without significant global emissions growth”.
This week, Copper Mountain Resort kicked off its carbon sequestration study, and over the next 10 years, scientists and resort leaders are hoping that ski slopes can contribute to the fight against the effects of climate change. The resort hosted a conservation summit on Wednesday, where Copper officials discussed the goals of the project with other ski industry and environmental leaders. Jeff Grasser, efficiency manager for Copper Mountain, said efforts have already been made to increase biodiversity of the land, but this study would continue meeting sustainability goals. Carbon sequestration is the process in which carbon dioxide is removed from the atmosphere and held in solid or liquid form. In this case, it would be in the soil, where most of the world’s carbon is stored. Grasser said the resort has developed a scientific-based study to prove that their efforts actually help increase the amount of carbon dioxide being taken out of the air…
Grasser said currently, the goal is to offset one gram of carbon per square meter. That would be about 50 metric tons of carbon per year. Specifically, he said that he is looking forward to seeing if the study could offset the resort’s backup motors for lifts since those are run by fossil fuels and are tested regularly to make sure they are functioning. Though it would not happen overnight, Grasser said building more biodiversity could help reach that goal…
Jennie DeMarco, assistant professor at Southwestern University in Texas, is a scientist assisting on the project and said that, in her work, she focuses on nature-based solutions. By doing restoration projects, people can increase carbon storage and avoid greenhouse gas emissions. She said the key with nature-climate solutions is that they can be implemented in a lot of different ecosystems. They are cost effective, she claimed, compared to new carbon-capture technology.
Just like any major disturbance, ski slopes can disrupt or degrade soils, which makes them less likely to store carbon. One solution that this project will study is adding compost to certain areas to improve soil health and encourage more sequestration and plant growth.
The clock is running on the climate crisis, but we have the tools and knowledge — and the crickets — that we need
The climate crisis is here, and heartbreak is all around us. The early promise of dramatic action from President Biden is sinking in the old mud bog of fossil-fuel politics. Meanwhile, despite 40 years of warnings from scientists and the decline in the cost of clean energy, carbon pollution is still increasing and the world is heating up as fast as ever. The final sentence of last February’s U.N.’s latest Intergovernmental Panel on Climate Change (IPCC) report on the impacts of that warming is stark and unequivocal: “Climate change is a threat to human well-being and the health of the planet. Any further delay in concerted global action will miss a brief and rapidly closing window to secure a livable future.” Or as U.N. Secretary-General António Guterres put it after an IPCC report on the mitigation of climate change was released this month: “Investing in new fossil fuels infrastructure is moral and economic madness.”
1. Tax carbon.
In February, Rhode Island Sen. Sheldon Whitehouse took to the Senate floor for his 280th “Time to Wake Up!” speech about the climate crisis. The centerpiece of Whitehouse’s plan was the need for a tax on fossil fuels. It is an argument that speaks to a truism of economics: to make something scarce, tax it…
2. Electrify everything.
In the U.S. there are roughly 290 million cars and trucks, 70 million fossil-fueled furnaces, 60 million fossil-fueled water heaters, 20 million gas dryers, and 50 million gas stoves. What if all those were electrified? Saul Griffith, an Australian American engineer and author of Electrify: An Optimist’s Playbook for Our Clean Energy Future, thinks electrification can reduce 80 percent of U.S. emissions by 2035…
3. Go local with solar.
It’s now obvious: The future is solar on homes, solar on apartment buildings, solar on malls, solar on parking lots, solar on fast-food joints, burrito stands, and strip clubs. With the sun, small is beautiful. Wasted space becomes a platform for power generation. With solar, cost has always been a problem, but that is ending now as the price of solar panels has plummeted over the past decade. Nobody pretends that you are going to make steel from solar, or that it will be the best way to generate power in every situation,but it is clean and reliable and won’t go down in a blackout like the one in 2021 that left 11 millions Texans freezing in the dark for days and was responsible for as many as 700 deaths…
4. Buy out coal plants.
Coal is the dirtiest, most carbon-intensive fossil fuel, responsible for 30 percent of global carbon emissions. The biggest coal burner is China, which consumes more coal than the rest of the world combined. Here in the U.S., coal is slowly being displaced by cheap gas, wind, and solar. But there are still 179 active coal plants, generating 20 percent of U.S. electricity. Shutting them down and replacing them with cleaner, cheaper energy is the fastest way to lower carbon emissions and slow the climate crisis. “The transition beyond coal is inevitable,” says Justin Guay, director for global climate strategy at the Sunrise Project. “But the timeline on which it happens isn’t.”
5. Start telling the truth about the climate crisis.
How much is that $2 million house on the beach going to be worth when there’s an octopus swimming through the living room? What’s going to happen to all those refineries on the Gulf Coast as the demand for oil plummets? Banks and corporations face huge financial risks as the age of climate disruption accelerates. One just-published report found around $343 billion in weather- and climate-related economic losses in 2021 alone, the third-costliest year on record. A 2019 study concluded that 215 of the world’s largest companies face nearly $1 trillion in climate-related risk as soon as 2024. Very little of this is disclosed in corporate financial reports. “The coronavirus pandemic has laid bare just how vulnerable the United States is to sudden, catastrophic shocks,” Sarah Bloom Raskin, Biden’s nominee to the Federal Reserve Board of Governors, wrote in The New York Times. “Climate change poses the next big threat.”
6. Build denser, fairer, more humane cities.
Urban life is far gentler on the planet than suburban life. People who live in cities spend less time stuck in traffic in their SUVs; they have better access to local food; they live in buildings that are more efficient. But cities need a climate upgrade too: more bikes, better public transit, more green space…
7. Get loud and hit them where it hurts.
The biggest roadblock to climate action has always been the cowardice and complicity of our political leaders. For many, the lack of significant accomplishments at last year’s Glasgow climate talks and the failure of Biden’s Build Back Better agenda have been a brutal awakening. “Activists have become jaded because there’s been a lot of promises from politicians without a lot of action to back it up,” says Dana Fisher, an environmental-activism expert at the University of Maryland and author of American Resistance. “A lot of young people are looking at other tactics now.”
8. Fund small-scale geo-engineering research.
Maybe Dr. Evil wants to deliberately fuck with the Earth’s climate, but nobody else does. Nevertheless, it’s probably inevitable, given the risks we face. There are many potential forms of geoengineering, from brightening clouds to stabilizing glaciers, but the technology that gets the most attention is solar engineering, which amounts to scattering particles in the stratosphere to reflect away sunlight and cool the Earth. Scientists know it works because it’s essentially what volcanoes do (particles injected into the stratosphere from Mount Pinatubo, which erupted in 1991, cooled the planet 0.6 C for more than a year, until they rained out of the sky)…
9. Eat crickets!
America’s (and, increasingly, the world’s) appetite for meat is barbecuing the planet. Livestock eat up a lot of land, drive deforestation, and are carbon-intensive in their own right. Without reforming industrial agriculture and reducing meat consumption, it will be virtually impossible to limit warming to 2 C, much less 1.5 C…
10. Fight and win the culture war.
Much has been said about the failure of Big Media to cover the climate crisis. It’s too often pigeonholed as an environmental issue rather than a slow-rolling planet-wide catastrophe. Or it’s infused with “both-sidesism,” in which journalists are duped into the false idea that there is any real debate about the fundamentals of climate science. Or it’s just not discussed at all. When Hurricane Ida slammed into the Gulf Coast late last summer, six of the biggest commercial TV networks in the U.S. — ABC, CBS, CNN, Fox, NBC, and MSNBC — ran 774 stories about Ida, an analysis by the watchdog group Media Matters found. Only 34 of those stories mentioned climate change. Mark Hertsgaard, the executive director of Covering Climate Now, an initiative dedicated to improving climate reporting, calls it “media malpractice.”
As the effects of a warming climate intensify and a sense of impending catastrophe grows stronger, it’s becoming easier to give in to environmental despair. Having spent the past five years studying the Arctic and traveling around Greenland, I feel the pull as well.
Glaciers and sea ice are melting at an alarming rate; temperatures are rising at a steady clip. To make matters worse, the Trump administration’s recent efforts to ignore a fact-based, scientific approach — rejecting, for instance, the use of computer projections to assess how a warming world might look after 2040 — leads me to worry that climate denialism is moving from the scientific fringes to the institutional center.
Still, it’s worth considering that things may not be as bad as they appear. I say this with a full understanding that most indicators are pointing in the wrong direction. Yet I also feel we’re in danger of losing sight of two crucial and encouraging aspects of our predicament.
The first is the extraordinary value of the climate knowledge we’ve amassed over the past 100 years — a vast archive of data and wisdom that gives us a fine-grained understanding of how the planet is warming and how we can change the trajectory we’re on.
The second is the emergence of potential solutions, the products of a half-century of technological innovation, which may help us avert the worst impacts of the carbon dioxide and other greenhouse gases we continue to release into the atmosphere. (Last year carbon dioxide emissions were the highest ever recorded.)
Almost certainly, these tools, if used wisely, could keep global average temperatures from rising 3.6 degrees Fahrenheit, or 2 degrees Celsius, from a preindustrial baseline. Even lesser levels of warming are probably hazardous, but that temperature is the point beyond which many scientists believe the planet will suffer irreversible impacts from extreme and dangerous warming.
Recently, the entrepreneur and technologist Saul Griffith undertook a study of energy consumption for the Department of Energy and concluded that, using the United States as an example, “decarbonization is not an unattainable ideal.” In fact, he surmised it would be far easier than one might think, given our wealth and technological know-how.
We don’t need to assume an attitude of fear and dread. Our scientific progress is a story of technological optimism, defined by an extraordinary sense of capability. It shows what might be built and gained in the coming decades, and not merely what could be lost.
First, let’s consider this: For all the terror and gloom that global warming portends, its discovery is one of the greatest achievements of modern science. Technology can now tell us everything from how many tons of ice were shed by the glaciers in Greenland over the past few years to how many millimeters the oceans rose. Indeed, almost every fact or idea that informs the climate debate, from the number of endangered species to the dangers of melting permafrost, results from countless scientists and engineers, working in the field and in laboratories, over the course of a century.
This knowledge derives not only from heroic human expeditions to tropics, oceans, icecaps and deserts, but also from exquisite orbiting satellites that constantly scrutinize natural systems and human impacts on those systems. We know how much we have to fix on this planet, because we’ve figured out how to measure just about everything.
In the past few years, some commentators have warned that modern society’s faith in technology has led to a mistaken belief that it will save the world. They embrace solutions that encourage widespread behavioral changes, like consuming less, traveling infrequently and adopting a plant-based diet. We’re likely to need both technological and personal transformations. But in the end, it’s technology that will save us, not only because it can but also because it will have to.
In many respects, technology is saving us already: by identifying the magnitude of the threat, providing the extraordinary computing power required to run climate models to predict the future, and enabling architects and engineers to design for resilience against tempestuous storms and encroaching seas.
Technology has made possible clean and efficient energy systems that wouldn’t have been achievable a few decades ago, including cheap solar panels, LED lighting and batteries for electric cars. We now have green buildings that reduce energy usage and an emerging class of solar cells known as perovskites that may greatly lower the costs of renewable energy, and we are developing techniques to produce concrete that absorbs carbon dioxide rather than emitting it.
There is even room for techno-skeptics. A movement for “natural climate solutions,” like planting vast forests and using agricultural methods that sequester carbon in the soil, will become increasingly important as technology in the form of “integrated assessment” computer models tells us how much this approach can mitigate warming trends.
The range of hypothetical geoengineering ideas for the Arctic is equally audacious. One is to use wind power in winter to pump water from the depths of the Arctic Ocean to the surface to thicken sea ice so that it is more resistant to melting. Sea ice is critical to cooling the planet, because it reflects sunlight that would otherwise be absorbed by the ocean, heating it. (The downside of this idea, which underscores the scope of the problem, is that 10 million windmills would be needed.)
Another idea is to geoengineer glaciers in Greenland and Antarctica to delay their melting. For instance, a 100-meter-high wall could be built across the five-kilometer-wide fjord in front of the Jakobshavn glacier in western Greenland to block the warm ocean currents that have been melting it. The glacier has contributed more to sea level rise than any other glacier in the Northern Hemisphere, though recently, that has slowed. There’s no proof yet this plan would work, and it would be hugely expensive. But as the idea’s proponents pointed out in the journal Nature, sea walls and flood defenses already cost tens of billions of dollars a year to build and maintain. “At this price, geoengineering is competitive,” they argued.
So, as much as we may be asking whether technology will save us, that’s the wrong question. The right question is: How will we use our current technologies — and our potential to develop new and better ones — to save ourselves?
Adopting a measure of technological optimism is not the same as adopting the blithe and complacent outlook of a techno-utopian. Neither is it to assume that we won’t suffer in the coming years from heat waves, storms and floods — or from elected officials who disregard the urgent need for action.
Rather, it’s to view 20th-century history as an accumulation of hard-won knowledge that arose from using our wits to understand the climate. It’s also to see that important technological and engineering achievements — developing mass transit systems, huge wind farms, even nuclear power plants — are possible when we choose to act, especially through our politics and policies.
Proof of this can be found in the most unlikely places. For the past few years I’ve been tracing the history of scientific discovery on the imperiled Greenland ice sheet. Greenland’s ice is so thick and so old that scientists can drill down and extract samples that contain evidence of what the environment was like thousands of years ago. With the help of lab instruments, researchers can reconstruct ancient temperatures and atmospheric conditions.
Amid the trace chemicals that turn up in the old ice, there is an unmistakable fingerprint of lead from a few thousand years ago — traces from silver smelters in Europe, during the height of the Roman Empire, which released lead into the air that was deposited on the icy surface of Greenland. In more recent records, we can see vestiges of the metal from the fumes of the early years of the Industrial Revolution and, later still, the residue from leaded gasoline.
Think of that the next time dread creeps in. Without question, reducing carbon dioxide is a far bigger challenge than reducing lead, and the stakes are much higher. But we now have a deeper well of knowledge and considerably better technologies. Indeed, if we don’t deploy the resources we now wield, many years into the future our story of failure will simply be this: We understood the threat, we were very smart and exceedingly capable. We had money and we had tools. And we chose not to act.
Jon Gertner is the author of the forthcoming “The Ice at the End of the World.”
The initiative, led by Alexandria Ocasio-Cortez, is ambitious, but some in the outdoor industry argue it’s the only hope for saving wild places from climate change
When 27-year-old climate activist Evan Weber thinks about climate change, he thinks about his childhood in Hawaii. He spent those years in the mountains, on beaches, and in the ocean. “Now the beaches that I grew up on don’t exist anymore,” he says. “Sea-level rise has swallowed them into the ocean. The mountains are green for much less of the year. The coral reefs are dying from ocean acidification killing both marine life and surf breaks.”
That’s what brought him, on November 13, to march on soon-to-be House Majority Leader Nancy Pelosi’s Capitol Hill office with around 150 other activists from a progressive group he cofounded called Sunrise Movement. They were demonstrating for a sweeping policy plan championed by congresswoman Alexandria Ocasio-Cortez called the Green New Deal. It is pitched as an economy-wide climate mobilization to connect environmental, social, and economic policies through legislation and would create everything from investment in federal green jobs for all who want them to a massive green-infrastructure program. The end result would be an overhauled national economy run on 100 percent renewable energy.
While these are lofty goals, and many are skeptical of the plan’s feasibility, advocates see it as setting the bar for a sufficient response to climate change that politicians can be held to. And the proposal is already gaining steam in Washington, D.C., as a platform to rally around heading into 2020: more than 40 lawmakers have endorsed Ocasio-Cortez’s call for a congressional select committee to map out the Green New Deal. Many in the outdoor industry are also paying attention to what could be the best hope to save our ski seasons and protect our public lands.
“It’s an approach that’s so comprehensive that it could be a way for the United States to lead in the direction of stabilizing the climate at two degrees Celsius,” says Mario Molina, executive director of the advocacy group Protect Our Winters. According to a climate assessment put out by the federal government last month, warming above that threshold (35.6 degrees Fahrenheit) could shorten ski seasons by half in some parts of the U.S. before 2050.
Climate change is already impacting snowpack, and ski resorts across America are scrambling to adapt. This past year, Aspen Snowmass launched a political campaign called Give a Flake to get its customers engaged in climate action, Squaw Valley spent $10 million on snowmaking equipment in 2017, and Vail is pursuing a sweeping program to weatherproof its operations. But, Molina explains, there’s a long way to go to address the ski industry’s fossil-fuel-intensive operations. He believes that something like the economy-wide transition to renewable energy proposed in the Green New Deal is the best way ski resorts will be able to significantly lower their carbon footprints. It would allow them, for example, to hook their resorts up to a central power grid that would spin their lifts with renewable energy and create more sustainable transit options to and from the slopes.
Amy Roberts, executive director of the Outdoor Industry Association (OIA), also sees the opportunity to link this kind of large-scale climate action with the outdoor economy, especially when it comes to public lands. An economy powered on 100 percent renewables would obviously erase any incentive for fossil-fuel companies to drill in places like the Arctic National Wildlife Refuge and Bears Ears National Monument. But the OIA is still watching to see how the politics around the Green New Deal shape up. The early support from lawmakers is encouraging, but they’re mostly Democrats. Roberts insists that policies to protect the climate and public lands need bipartisan support, but she thinks that the outdoor industry can help make that happen. “When you look at who takes part in our activities, whether it’s hiking, camping, hunting, or fishing, there are both Republicans and Democrats,” she says. “That’s an opportunity to unite and bring a compelling message that’s separate and apart from what the environmental community is doing.”
As proof, she points to the Georgia Outdoor Stewardship Act. In November, Peach State voters passed the measure, in which sales tax from sporting goods and outdoor equipment is used to fund parks and trails, with 83 percent support. In the same election, the governor’s race was so divided that it went to a recount.
Even with glimpses of bipartisan support for the environment, Molina worries that the main hurdle Green New Deal legislation will face is influence from the fossil-fuel industry. Its lobbyists donated more than $100 million to campaigns in the 2016 election, and in 2018 raised $30 million to defeat a Washington State ballot measure that would have added a modest carbon tax on emissions and used the revenue to fund environmental and social programs. Additionally, former oil lobbyist David Bernhardt was tapped to replace Ryan Zinke as interior secretary in December.
But activists like Weber are not giving up. As part of their push for a Green New Deal, they have called for members of the Democratic leadership to reject campaign contributions from fossil-fuel interests. And a few weeks after Weber was in Nancy Pelosi’s office, he and more than 1,000 young people were back in Washington, D.C., this time storming Capitol Hill in a daylong push to get lawmakers to endorse the Green New Deal, an effort that resulted in nearly 150 arrests. They remain unfazed by claims that the plan’s goals are too large. “A Green New Deal is the only proposal put forth by an American politician that’s in line with what the latest science says is necessary to prevent irreversible climate change,” Weber says. “It could mean the difference between whether future generations around the world get to have the same formative experiences in nature that I did—or not.”
Alexandria Ocasio-Cortez. Elizabeth Warren. Beto O’Rourke. Those are just a few of the high-profile names either leading the development of or jumping to endorse today’s environmental cause célèbre, the Green New Deal. Inside congressional halls, at street protests, and, of course, on climate Twitter — it’s hard to avoid the idea, which aims to re-package ambitious climate actions into a single, wide-ranging stimulus program.
The Green New Deal is being promoted as a kind of progressive beacon of a greener America, promising jobs and social justice for all on top of a shift away from fossil fuels. It’s a proposal largely driven by newcomers to politics and environmental activism (and supported, however tentatively, by several potential presidential candidates and members of the Democratic political establishment). The plan aspires to bring together the needs of people and the environment, outlining “a historic opportunity to virtually eliminate poverty.”
But within the broader environmental movement, not everyone was initially gung-ho on the Green New Deal — at least not without some stipulations.
To understand the debate surrounding the Green New Deal, you need to look beyond its recent prominence in Beltway political circles to the on-the-ground organizations that make up the environmental justice movement. Newcomers like Ocasio-Cortez may be leading the charge, but grassroots leaders who have spent years advocating for low-income families and neighborhoods of color most impacted by fossil fuels say their communities weren’t consulted when the idea first took shape.
For all the fanfare, there isn’t a package of policies that make up a Green New Deal just yet. And that’s why community-level activists are clamoring to get involved, help shape the effort, and ensure the deal leaves no one behind.
Something Old, Something New
Although the term “Green New Deal” has evolved over time, its current embodiment as a complete overhaul of U.S. energy infrastructure was spearheaded by two high profile entities: progressive darling and first-term Representative Alexandria Ocasio-Cortez, and the Sunrise Movement, an organization formed in 2017 by young people hellbent on making climate change the “it” issue.
In November 2018, Ocasio-Cortez, with support from Sunrise, called for a House select committee to formulate the package of policies. More than 40 lawmakers signed on to support the draft text. Then shortly before the end of the year, Nancy Pelosi, now the speaker of the House, announced the formation instead of a “Select Committee on the Climate Crisis.”
It wasn’t exactly a win for the leaders of the new environmental vanguard. Sunrise tweeted its displeasure at the committee’s pared-down ambition, taking umbrage with its lack of power to subpoena (a condition for which Ocasio-Cortez had advocated) and the fact that politicians who take money from fossil fuel interests would not be excluded from sitting on it.
The fuss over who gets a say in the formation of the Green New Deal goes back further than Ocasio-Cortez’s or Sunrise’s friendly-ish feud with establishment Democrats. The Climate Justice Alliance, a network of groups representing indigenous peoples, workers, and frontline communities, says its gut reaction to the Green New Deal was that it had been crafted at the “grasstops” (as opposed to the grassroots).
Shortly after Ocasio-Cortez put out her proposal for a select committee, the alliance released a statement largely in support of the concept, but with a “word of caution”: “When we consulted with many of our own communities, they were neither aware of, nor had they been consulted about, the launch of the GND.”
Leaders at the alliance surveyed its member organizations — there are more than 60 across the U.S. — and put together a list of their concerns. Unless the Green New Deal addresses those key points, the alliance says, the plan won’t meet its proponents’ lofty goal of tackling poverty and injustice. Nor will the deal gain the grassroots support it will likely need to become a reality.
“What we want to do is strengthen and center the Green New Deal in environmental justice communities that have both experience and lived history of confronting the struggle against fossil fuel industries,” Angela Adrar, executive director of the alliance, told Grist.
Grist asked several indigenous and environmental justice leaders: If the Green New Deal is going to make good on its promises, what will it take? Here’s what they said.
A more inclusive and democratic process that respects tribal sovereignty
As details get hashed out on what a Green New Deal would actually include, longtime environmental justice organizers say their communities need to be the ones guiding the way forward. “The way that the plan was developed and shared is one of its greatest weaknesses,” Adrar says. “We want to be able to act quickly, but we also want to act democratically.”
She adds that involving the grassroots is especially important in the wake of the 2018 midterm elections, which ushered in many new congressional members pledging to focus on the underrepresented communities they come from. The Climate Justice Alliance is calling for town halls (with interpreters for several languages) to allow communities to help flesh out policies to include in the Green New Deal.
Some of the disconnect could be generational, says Tom Goldtooth, executive director of the Indigenous Environmental Network. Many of the leaders espousing the Green New Deal are young people. He says that he and his colleagues were caught off-guard when they saw the plan on social media and that when his network reached out to its members, there was little familiarity or understanding of the Green New Deal.
“Maybe the way of communication of youth is different than what we’ve found in the environmental justice movement and our native movement around the value of human contact — face-to-face human contact,” he says. “We’re asking that leadership of the Green New Deal meet with us and have a discussion how we can strengthen this campaign with the participation of the communities most impacted.”
Any retooling of America’s energy infrastructure will undoubtedly venture into Native American tribes’ lands, where there are already long-standing battles over existing and proposed pipeline expansions, as well as fossil fuel facilities. The United Nations Declaration on the Rights of Indigenous Peoples calls for “free, prior, and informed consent” from tribes before developers begin any project on their land. So indigenous environmental groups say there needs to be respect for tribal sovereignty and buy-in from tribes for a Green New Deal to fulfill its promise of being just and equitable.
Green jobs should be great jobs
There has been a lot of talk in Green New Deal circles about uplifting poor and working-class communities. Advocates have floated ideas ranging from a job-guarantee program offering a living wage to anyone who wants one to explicitly ensuring the rights of workers to form a union.
But as workers’ rights organizations point out, energy and extractive industries have provided unionized, high-paying jobs for a long time — and they want to make sure workers can have the same or a better quality of life within green industries.
“There’s been a long history of workers that have been left hanging in transition in the past,” says Michael Leon Guerrero, executive director of the Labor Network for Sustainability, which has been working to bridge divides between labor and environmental issues. “For that reason, there’s quite a bit of skepticism in the labor sector.”
Joseph Uehlein, who founded the Labor Network for Sustainability, adds that there needs to be more than just the promise of jobs to entice labor to support a Green New Deal. “Every presidential candidate in my lifetime talks about job creation as their top priority,” he says. “Over the last 40 years, those jobs have gotten worse and worse. A lot of jobs are not so good, requiring two or three breadwinners to do what one used to be able to do.”
Uehlein hopes an eventual Green New Deal will ensure not just jobs that guarantee a living wage, but will go one step further. “We always talk about family-supporting jobs,” he says. “It’s not just about living, it’s about supporting families.”
Do No Harm
Any version of a Green New Deal would likely ensure that the U.S. transitions away from fossil fuels and toward renewable sources of energy — with Ocasio-Cortez setting the bold target of the nation getting 100 percent of its energy from renewables within 10 years.
But defining what exactly counts as “renewable energy” has been tricky. There are plenty of sources of energy that aren’t in danger of running out and don’t put out as many greenhouse gases as coal or oil, but are still disruptive to frontline communities. Garbage incineration is considered a renewable energy in some states, but it still emits harmful pollutants. And when it comes to nuclear energy or large-scale hydropower, the associated uranium extraction and dam construction have destroyed indigenous peoples’ homes and flooded their lands.
The Climate Justice Alliance is also pushing to exclude global warming interventions like geoengineering and carbon capture and sequestration, which they believe don’t do enough to address the root causes of global warming. Both technologies have to do with re-trapping or curbing the effects of greenhouse gases after they’ve been produced. “Carbon capture and sequestration, it’s a false solution from our analysis,” Goldtooth says. The focus needs to be on stopping greenhouse gases from getting into the atmosphere in the first place, he and other critics argue.
As the alliance sees it, a future in which the planet survives requires a complete transition away from fossil fuels and an extractive economy, and toward a regenerative economy with less consumption and more ecological resilience.
Goldtooth and his colleagues are calling for solutions that rein in damaging co-pollutants on top of greenhouse gases. And they support scalable solutions — like community solar projects — that are are popping up in some of the neighborhoods that are most affected by climate change.
A good start
Even though the Green New Deal faces many political obstacles, its proponents are still pushing forward at full speed. “We are calling for a wartime-level, just economic mobilization plan to get to 100% renewable energy ASAP,” Ocasio-Cortez tweeted on New Year’s Day.
Scientists recently estimated that the world has only 12 years to keep average global temperatures from increasing beyond 1.5 degrees Celsius (2.7 degrees Fahrenheit) — the upper limit which many agree we can’t surpass if we want to avoid a climate crisis. The urgency around the latest climate change timeline has brought a lot of new advocates to the table.
According to John Harrity, chair of the Connecticut Roundtable on Climate and Jobs and a board member at the Labor Network for Sustainability, the labor movement is becoming more willing to engage on ways to address climate change. “I think the Green New Deal becomes a really good way to put all of that together in a package,” he says. “That evokes for a lot of people the image of a time when people did all pull together for the common good.”
Elizabeth Yeampierre, steering committee co-chair of the Climate Justice Alliance and executive director of the Brooklyn-based grassroots organization, UPROSE, which works on issues cutting across climate change and racial justice, calls the Green New Deal “a good beginning for developing something that could really have lasting impacts and transformation in local communities and nationwide.”
Since the alliance put out its recommendations, Yeampierre says she’s been in regular contact with both the Sunrise Movement and Ocasio-Cortez’s office. “To their credit they were responsive and have made themselves available to figure out how we move forward in a way that doesn’t really step over the people,” she explains.
The language in Ocasio-Cortez’ draft proposal has already changed — it now includes clauses to “protect and enforce sovereign rights and land rights of tribal nations” and “recognize the rights of workers to organize and unionize.” The document has doubled in length since it was put out in November (at time of publication, it is 11 pages long) and will likely include new edits in the coming days.
Varshini Prakash, a founding member of the Sunrise Movement (and a 2018 Grist 50 Fixer), says she agrees with the Climate Justice Alliance’s recommendation that a Green New Deal prioritize the needs of workers, frontline communities, communities of color, and low-income communities. “Their critiques,” Prakash tells Grist, “are fully valid, and I appreciate what they’re bringing.”
The broad overview of a Green New Deal in Ocasio-Cortez’s proposal for a select committee, Prakash says, was hashed out quickly after the representative’s team approached Sunrise late last year. (Ocasio-Cortez did not immediately respond to Grist’s inquiry). “This was very rapid fire, it happened on an extremely tight timescale,” she says. “We didn’t have a lot of time to do the broad consultation we wanted.”
But Prakash, Yeampierre, and other leaders in the movements for environmental and climate justice are working to make sure there are more folks on board moving forward.
“Climate change isn’t just going to threaten our communities — it’s also going to test our solidarity, it’s going to test how we build relationships with each other,” Yeampierre says. “So I think the Green New Deal can be used as an opportunity to show that we can pass that test.”
Two years ago this weekend I was in British Columbia, with two must-see items on my agenda. I had spent the previous five days, courtesy of the Canadian government, visiting first Toronto and then Vancouver. The consulate in Denver, where I live, wanted journalists and others to see and hear about all the wondrous things being done in Canada’s two marquee cities to quell greenhouse gas emissions.
After our final Vancouver visit, on my own agenda and on my own dime, I rented a car and drove up the Sea-to-Sky Highway. In Whistler, I wanted to see how the ski company was helping save the planet. And in Squamish, 40 minutes why of Whistler, along Howe Sound, I wanted to see where a great experiment was underway that might help save Whistler’s snow. My curiosity about the Squamish project was well founded as recent news shows.
In Whistler, I was graciously given a tour of the mountain, the Peak 2 Peak gondola, the bike park, and more. Our last stop, the Fitzsimmons Creek run-of-the-river hydroelectric project, was the most important to me. Though it wasn’t all that much to look at, it represented perhaps the most important effort up until then of a ski company taking responsibility for its role in this giant energy challenge facing humanity.
Despite the Fitzsimmons hydroelectric project, despite the new solar farm that makes the Colorado ski area of Wolf Creek 100 percent solar powered, despite all the wondrous things Vancouver and Toronto are doing, we’re still speeding into an unmapped climatic wilderness.
In April, we tripped across the threshold of 410 parts per million, a 130 ppm increase since the start of the industrial age two centuries ago. Most of that increase has occurred since I was born in the 1950s. We’re accelerating our emissions, almost triple the annual rate from when I was a youngster, learning to ride a clunker of a bicycle. In the process we’ve already elevated our temperatures by 1.2 to 1.3 degrees C.
Now we’re racing toward 450 ppm. Unless we slow our emissions, says Scientific American, we’ll hit that mark in about 18 years.
Climate scientists don’t know for sure that anything calamitous will happen at 450 ppm. It could be just another increment, like a hair of once-brown head turning gray: deeper droughts, longer heat waves, more powerful typhoons and hurricanes. And, of course, warmer. Or it could be much worse, a big spurt of change. Some of the uncertainty has to do with the feedback mechanisms, such as the thawing of methane, a far more powerful heat-trapping gas, in the Arctic tundra. These are the unexpected, nonlinear, and frightening outcomes that scientists warn could result from pushing the climate system too hard.
Ice cores extracted from glaciers in Greenland, Antarctica, and elsewhere provide surprisingly insightful mirrors of the past. For example, the Greenland ice from 1,700 to 2,500 years ago shows levels of lead that indicate lead and silver mining and smelting by the Greeks and Romans. Ice cores also show CO2 in the atmosphere. Those now are 100 ppm higher than at any time in the last 800,000 years.
Writing in the New York Times Magazine last year, Jon Gertner noted the last time atmospheric CO2 levels were as elevated as now, three million years ago, sea levels were most likely 45 feet higher and giant camels roamed above the Arctic Circle.
That’s where Squamish and geoengineering comes in. Many scientists have concluded that the only way to avert the perhaps intolerable climatic changes is to conduct massive geoengineering, to reverse the effects of global warming. Geoengineering is an umbrella word, kind of like snow sliding, for two broad categories of activities.
One type of geoengineering seeks to deliberately tinker with the climate, to reverse existing and continued effects. One such idea, for example, would attempt to replicate the effect of volcanoes. In 1991, for example, Mt. Pinatubo, a volcano in the Philippines, exploded, pushing a plume of gas and ash—including nearly 20 million tons of sulfur dioxide—into the atmosphere, eventually reaching an altitude of 39 kilometers. The most particulates went skyward since the eruption of Krakatoa in 1883. The aerosols formed a global layer of sulfuric acid haze, cooling global temperatures.5 degrees C in the years 1991-93. Krakatoa had had a similar effect, depressing temperatures by as much as 1.2 degrees C in the northern hemisphere and also helping produce 38 inches of rain in Los Angeles, which averages 15 inches.
All manner of ideas have been formulated to intentionally disrupt the climate. One idea would have us deploying mirrors, perhaps in deserts or perhaps in outer space, to reflect back light into space. Another idea is to brighten clouds, to make them more reflective. Still another idea, crudely employed, would be to scatter materials over glaciers, once again to reduce the albedo effect of the native snow and ice. Then others have toyed with dumping iron into the ocean, to spur the growth of carbon-sucking algae. None of these ideas have gotten very far.
The second major type of geoengineering seeks to withdraw carbon dioxide from the atmosphere. The International Panel on Climate Change’s 2014 report surprised many by identifying 116 scenarios in which global temperatures could be prevented from rising more than 2 degrees C. Of these, 111 scenarios involve sucking massive quantities of CO2, from the atmosphere. As Wired magazine noted in a story last December, the goal is to attain “negative emissions,” perhaps lowering CO2, emissions below 400 ppm, even down to 350 ppm, as Bill McKibben proposes.
Trees suck carbon, but they do grow slowly, don’t they? Other ideas involve growing plants and then harvesting them, burning them, and producing energy in that way. Such ideas have generally been dismissed as impractical for the kind of carbon reduction needed in the next 30 years, simply because of the space required. As Wired noted, just growing the crops needed to fuel these bio-energy plants would require a landmass one to two times the size of India—and this transformation would have to occur within the lifetimes of the millennial generation.
In Squamish, a relatively new company called Carbon Engineering is capturing air then using industrial processes to remove the carbon dioxide. Several similar processes are being tried in other experiments around the world.
David Keith, now of Harvard University, founded the company in 2015. He obtained funding from two billionaires, Microsoft founder Bill Gates and Norman Murray Edwards, who has a big stake in the oil sands of Alberta and also owns the Fernie, Kimberley, Kicking Horse, and other resorts of British Columbia.
Being of a different income class than these billionaires, I stayed at the hostel in Squamish, sharing a room with about 35 other guys. (There are times, if rare, when I am actually glad for my hearing loss.) The next morning I drove around Squamish, visiting the Sikh temple, watching immigrant families frolic on the waterfront, and admiring the giant rock formation overlooking the town. Only later, after returning to Vancouver, did I learn that a base jumper had leaped to his death from the granitic monolith of the Stawamus Chief at almost precisely that same time. The parachute of the victim, an ex-Marine, had failed to deploy.
At length, I found Carbon Engineering on a sliver of land jutting into Howe Sound. Peering over the locked gate of the chain-link fence that Sunday morning I saw a long metal shed, several tanks, pipes, and a shaft.
A story in the Guardian described the great challenge of this alchemy using the example of M&Ms. If you were allowed to eat every red M&M in a bag, it would be easy to do so if they were but one of every 10 in a bag. But, if the concentration fell to one in every 2,500—the concentration of CO2 in the atmosphere—you might just give up on the red M&M’s.
Carbon Engineering in its plant at Squamish has modified old processes to address this challenge. The process uses a strong hydroxide solution to capture CO2 in a structure modeled on an industrial cooling tower and convert it into a carbonate. Next small pellets of calcium carbonate are precipitated from the carbonate solution. The calcium carbonate, once dried, is then heated, to break apart the CO2 and residual calcium oxide.
According to the company website, the plan is to move to commercialization, creating industrial-scale air-capture facilities outside of cities and on non-agriculture land.
But there’s more. Carbon Engineering’s vision combined this direct air capture technology with water electrolysis and fuels synthesis to produce liquid hydrocarbon fuels. In this process, the CO2 and hydrogen are thermocatalytically reacted to produce syngas and reacted again to produce hydrocarbons. In principle, a wide variety of hydrocarbons can be generated, but the company says it intends to focus on providing a product that replaces diesel and jet fuel. The plant at Squamish has been producing a barrel a day of synthetic fuel.
“If we’re successful at building a business of carbon removal, these are trillion-dollar markets,” Adrian Corless, then chief executive of Carbon Engineering, told Kolbert.
But could it do so cost-effectively? That has been the big question facing Carbon Engineering and every other company organized to suck carbon dioxide out of the atmosphere. Cost estimates had run up to $600 a ton or even more.
Scale is what matters. Can the process be scaled? That was the chief criterion in Richard Branson’s Virgin Earth Challenge. He offers $25 million for the first scalable solution for removing greenhouse gases. So far, the money has been unclaimed.
On June 7, Carbon Engineering announced publication of a peer-reviewed paper in the energy journal called Joule that declares that the process tested at Squamish since 2015 has been refined such that it can done for as low as $94 per metric ton. The news—if not all the paper’s qualifying statements about financial assumptions and so forth—was quickly splashed around on BBC and other international news organizations.
“Imagine driving up to your local gas station and being able to choose between regular, premium or carbon-free gasoline,” offered the National Geographic.
The BBC, after describing the “tangle of pipes, pumps, tanks, reactors, chimneys and ducts on a messy industrial site,” concluded that the process underway at Squamish “could just provide the fix to stop the world tipping into runaway climate change.”
“I hope this changes views about this technology from being this thing which people think is a magic savior, which it isn’t, or that it is absurdly expensive, which it isn’t, to an industrial technology that is do-able and can be developed in a useful way,” David Keith, a founder of Carbon Engineering, told BBC News.
In 2010, I had met Keith in Calgary, where he was then teaching, with dual appointments at the Massachusetts Institute of Technology and the University of Calgary. This was on the tail-end of a trip to Fort McMurray, also courtesy of the Canadian government, designed to show-and-tell why the oil/tar sands were not such a terrible thing.
To my surprise, the Canadian consulate media liaison in Denver—a former bump-skier from Vail—had wanted us to meet with David Keith. I was impressed, because even then I was aware of some of Keith’s big-picture thinking.
Keith, now 54, comes across as somebody deeply loving of the same things as most people in mountain towns do. He grew up in Canada, the son of a researcher with the Canadian Wildlife Service who did groundbreaking work on the insidious effects of pesticides; his mother was a historian.
After graduating from the University of Toronto with a degree in physics, Keith took journeys to the Arctic. In the first trip he camped alone in a remote region of Labrador for three weeks. Then he spent four months living in a plywood shack in the middle of the Arctic Archipelago, tracking walruses with a polar bear biologist. He has said it was one of the happiest times of his life.
He continues to seek out solitude in wonderful places. On a recent honeymoon he went backpacking in northern British Columbia. Protecting the climate of existing ecosystems and places clearly drives him.
Some of that thinking has been at meetings convened during the 1990s at the Aspen Global Change Institute. One of the speakers Keith heard had been a proponent of using nuclear devices for massive earth-moving goals, such as digging new canals. But the speaker by then was talking about geoengineering as a way of addressing the massive challenge of carbon dioxide emissions.
As a civilization, we’ve done our best to tinker with weather. Jeff Goodell, in his 2010 book “How to Cool the Planet,” offers a delightful history of the flimflam artists of the early 20th century who promised they could deliver rain to soak farmers’ fields and fill reservoirs in San Diego. After World War II, such efforts became more scientific, with the deliberate seeding of clouds with silver iodide and other substances to produce rain and snow.
Vail, the ski area operator, has been paying to seed clouds over Vail Mountain since a disastrous drought in 1977 as well as other of its properties. So do major water utilities, such as Denver. This is despite a major, 10-year study bankrolled by Wyoming that found only marginal success of cloud seeding.
The U.S. government, through a program called Project Plowshare, in the 1960s and early 1970s explored the idea of using nuclear devices to move massive amounts of Earth. One of the ideas was to thoroughly shake up the subterranean in order to unloose natural gas encased in tight rocks. Call it nuclear fracking. One of those blasts occurred west of Aspen and Vail in 1969, near the town of Parachute. It created rubble, all underground, but no natural gas worth anything. It was radioactive. At last, the U.S. government pulled the plug, in what one Cold War analyst says “the reluctant admission that a nuclear utopia was not imminent.”
In Calgary, Keith wouldn’t singularly bad-mouth the tar sands. (Because this was a Canadian government trip, it was always “oil sands,” and that’s what Keith said, too). But what stands out from my notes almost eight years later is his insistence that all our efforts to that day had been largely symbolic. “For the United States and Canada, motivation for action that goes beyond symbolic is very low,” he said.
“It’s important to be realistic about this,” he added.
In his 2013 book, “The Case for Climate Engineering,” Keith articulated the same thought about a disconnect between efforts and outcome. “Why has the spending on clean energy produced such meager results?” he asked. “Either the cost of cutting emissions is much higher than analysts’ estimates of what’s needed or the money is getting grossly misspent. Carbon emissions are so large that deep cuts can only be realized by actions that are cost-effective and scalable.”
Cost effective and scalable remain the key words. The paper in the journal published last week described a rate of “levelized cost per tonne of CO2 captured from the atmosphere ranging from $94 to $232.”
That is still a wide range, and, in any event, it’s well above the world’s highest carbon tax, British Columbia’s $35 per tonne; it is set to reach $50 a tonne by 2021. The point is that the price of carbon emissions must rise substantially or the cost of removing it must be lowered substantially before there will be any traction.
Keith has also been working in the other realm of geoengineering. Keith and another Harvard scientist, Frank Keutsch, had planned to launch a high-altitude balloon, tethered to a gondola with propellers and sensors, to spray a fine mist of materials such as sulfur dioxide, alumina, or calcium carbonate into the stratosphere above Arizona. The sensors, as he told MIT Technology Review, would measure the reflectivity of the particles, the degree to which they disperse or coalesce, and the way they interact with other compounds in the atmosphere.
Should we even pretend to think that technology can come to our aid? Conferences and papers so far debate this very question. Some see it as akin to setting off bombs underground in Colorado. Even Keith has said repeatedly that geoengineering is secondary to reducing our emissions.
Many scientists have argued we shouldn’t even try. Even if successful, would it then allow us to dither on this path toward making a giant energy transition? We could just spew more and more carbon into the atmosphere. As the fracking revolution has taught us, we’re a very inventive species at figuring out how to get carbon from underground.
What about unintended consequences? When inventors in the Silicon Valley were creating smart phones, they probably weren’t imagining that people would be reading their phones as they drove down highways. For that matter, when Henry Ford began mass-producing cars in Detroit, he could not have imagined that one day transportation, primarily from cars and trucks, would be the leading emitter of CO2, emissions. He was creating a greater good, not a greater problem.
Then again, do we have a choice? We’re disrupting the climate through our small, unseen emissions of carbon dioxide millions and millions of times each day across the planet. We’ve already jumped off a cliff. Like the base jumper at the Chief, we had better hope we have a parachute to deploy. It’s too soon to say whether the industrial process for removing carbon dioxide from the air in the metal building in Squamish will be that parachute. But keep your eye on it. It’s terribly important.
On Wednesday, scientists at the University of California in San Diego confirmed that April’s monthly average atmospheric carbon dioxide concentration breached 410 parts per million for the first time in our history.
We know a lot about how to track these changes. The Earth’s carbon dioxide levels peak around this time every year for a pretty straightforward reason. There’s more landmass in the northern hemisphere, and plants grow in a seasonal cycle. During the summer, they suck down CO2, during the winter, they let it back out. The measurements were made at Mauna Loa, Hawaii — a site chosen for its pristine location far away from the polluting influence of a major city.
Increasingly though, pollution from the world’s cities is making its way to Mauna Loa — and everywhere else on Earth.
In little more than a century of frenzied fossil-fuel burning, we humans have altered our planet’s atmosphere at a rate dozens of times faster than natural climate change. Carbon dioxide is now more than 100 ppm higher than any direct measurements from Antarctic ice cores over the past 800,000 years, and probably significantly higher than anything the planet has experienced for at least 15 million years. That includes eras when Earth was largely ice-free.
Not only are carbon dioxide levels rising each year, they are accelerating. Carbon dioxide is climbing at twice the pace it was 50 years ago. Even the increases are increasing.
That’s happening for several reasons, most important of which is that we’re still burning a larger amount of fossil fuels each year. Last year, humanity emitted the highest level of greenhouse gas emissions in history — even after factoring in the expansion of renewable energy. At the same time, the world’s most important carbon sinks — our forests — are dying, and therefore losing their ability to pull carbon dioxide out of the air and store it safely in the soil. The combination of these effects means we are losing ground, and fast.
Without a bold shift in our actions, in 30 years atmospheric carbon dioxide will return back to levels last reached just after the extinction of the dinosaurs, more than 50 million years ago. At that point, it might be too late to prevent permanent, dangerous feedback loops from kicking in.
This is the biggest problem humanity has ever faced, and we’ve barely even begun to address it effectively. On our current pace, factoring in current climate policies of every nation on Earth, the best independent analyses show that we are on course for warming of about 3.4 degrees Celsius above pre-industrial levels, enough to extinguish entire ecosystems and destabilize human civilization.
Climate change demands the urgent attention and cooperation of every government around the world. But even though most countries have acknowledged the danger, the ability to limit our emissions eludes us. After 23 years of United Nations summits on climate change, the time has come for radical thinking and radical action — a social movement with the power to demand a better future.
Of the two dozen or so official UN scenarios that show humanity curbing global warming to the goals agreed to in the 2015 Paris Accord, not one show success without the equivalent of a technological miracle. It’s easier to imagine outlandish technologies, like carbon capture, geoengineering, or fusion power than self-control.
Our failed approach to climate change is mostly a failure of imagination. We are not fated to this path. We can do better. Yes, there are some truly colossal headwinds, but we still control our future. Forgetting that fact is sure to doom us all.
On Tuesday, the Mauna Loa Observatory recorded its first-ever carbon dioxide reading in excess of 410 parts per million (it was 410.28 ppm in case you want the full deal). Carbon dioxide hasn’t reached that height in millions of years. It’s a new atmosphere that humanity will have to contend with, one that’s trapping more heat and causing the climate to change at a quickening rate.
In what’s become a spring tradition like Passover and Easter, carbon dioxide has set a record high each year since measurements began. It stood at 280 ppm when record keeping began at Mauna Loa in 1958. In 2013, it passed 400 ppm. Just four years later, the 400 ppm mark is no longer a novelty. It’s the norm.
“Its pretty depressing that it’s only a couple of years since the 400 ppm milestone was toppled,” Gavin Foster, a paleoclimate researcher at the University of Southampton told Climate Central last month. “These milestones are just numbers, but they give us an opportunity to pause and take stock and act as useful yard sticks for comparisons to the geological record.”
Earlier this year, U.K. Met Office scientists issued their first-ever carbon dioxide forecast. They projected carbon dioxide could reach 410 ppm in March and almost certainly would by April. Their forecast has been borne out with Tuesday’s daily record. They project that the monthly average will peak near 407 ppm in May, setting a monthly record.
Carbon dioxide concentrations have skyrocketed over the past two years due to in part to natural factors like El Niño causing more of it to end up in the atmosphere. But it’s mostly driven by the record amounts of carbon dioxide humans are creating by burning fossil fuels.
“The rate of increase will go down when emissions decrease,” Pieter Tans, an atmospheric scientist at the National Oceanic and Atmospheric Administration, said. “But carbon dioxide will still be going up, albeit more slowly. Only when emissions are cut in half will atmospheric carbon dioxide level off initially.”
Even when concentrations of carbon dioxide level off, the impacts of climate change will extend centuries into the future. The planet has already warmed 1.8°F (1°C), including a run of 627 months in a row of above-normal heat. Sea levels have risen about a foot and oceans have acidified. Extreme heat has become more common.
All of these impacts will last longer and intensify into the future even if we cut carbon emissions. But we face a choice of just how intense they become based on when we stop polluting the atmosphere.
Right now we’re on track to create a climate unseen in 50 million years by mid-century.
Lisa Dilling, assistant professor of Environmental Studies at the University of Colorado Boulder, is the new director of the Western Water Assessment (WWA), an applied research program that addresses societal vulnerabilities related to climate, particularly in the area of water resources.
WWA is part of the Cooperative Institute for Research in Environmental Sciences (CIRES) at CU-Boulder, and is funded primarily by NOAA’s Regional Integrated Sciences and Assessments Program.
Dilling is also a CIRES Fellow and a member of CIRES’ Center for Science and Technology Policy Research at CU-Boulder. Her research focuses on decision making, the use of information and science policies related to climate change, adaptation, geoengineering and carbon management. Her current projects examine drought in urban water systems, water governance and climate change, municipal adaptation to hazards, decision making in public lands management, and knowledge for adaptation in Tanzania. Dilling has authored numerous articles and is a co-editor of the book Creating a Climate for Change: Communicating climate change and facilitating social change from Cambridge University Press.
WWA is based in Boulder but works across the Intermountain West in Colorado, Utah, and Wyoming. Its mission is to identify and characterize regional vulnerabilities to and impacts of climate variability and change, and to develop information, products, and processes to assist decision makers throughout the Intermountain West. For example, WWA staff are producing a Climate Change in Colorado report for the state of Colorado; helped author the National Climate Assessment released this spring; and are conducting work to understand how emergency managers and others use (or do not use) NOAA streamflow forecasts.
Kristen Averyt, WWA’s previous director, will now focus on her position as Associate Director for Science at CIRES, and she will continue to conduct research and lead projects for the WWA.