Greenland Ice Sheet Beats All-Time 1-Day Melt Record — EOS #ActOnClimate

Greenland Ice Sheet melting August 2019. Photo credit: PBS

From EOS (Jenessa Duncombe):

More ice melted from the ice sheet on 1 August 2019 than any other day on record.

The Greenland ice sheet broke records on 1 August 2019 by losing more water volume in 1 day than on than any other day since records began in 1950, shedding 12.5 billion tons of water into the sea.

The record-breaking day came during a weeklong extreme melt event hitting Greenland due to soaring temperatures and low snow accumulation over the winter. The warmer temperatures are part of a heat wave that scorched Europe in late July, setting records in several countries including Germany, France, and the Netherlands.

Air temperatures rose to 10°C above average in places in Greenland this week and peaked above the freezing point for hours at a time at the ice sheet’s summit more than 3,200 meters above sea level. The months of April, May, June, and July also had higher than average temperatures in Greenland.

The volume of water melted per day on the ice sheet this week has increased as temperatures have climbed. The extreme melting on 1 August liquified enough ice to fill 5 million Olympic-sized swimming pools with water, accounting for 12.5 gigatons of water. The latest findings come from observations and model calculations from the National Snow and Ice Data Center (NSIDC) at the University of Colorado.

“Any ice that we’re losing from the ice sheet is being put into the ocean and adding to sea level,” research scientist Twila Moon of NSIDC told Eos.

Greenland is a major contributor to global sea level rise and is projected to contribute 5–33 centimeters of sea level rise globally by 2100, according to a June 2019 study in Science Advances. The University of Colorado estimated that this week’s melt will contribute 0.11 millimeter of sea level rise to global oceans.

The last extreme ice melt event in Greenland occurred in 2012, when 98% of the ice sheet’s area experienced melting. The 2019 event is smaller by area, with an estimate of about 60% on 31 July. Scientists do not believe that the melt extent will surpass that of 2012 but speculate that the surface mass balance lost, which includes both melting and snow accumulation, could rival it. “There’s no doubt that this is a direct consequence of human-caused climate change,” Moon said, noting that humans are “active players” in determining how much ice melts around the globe.

However, “the beautiful thing is that there are many things that any individual can do,” Moon said. Reaching out to elected representatives, business leaders, and utility companies about lowering greenhouse gas emissions are three ways to get involved, she said.

From The Huffington Post (Lydia O’Connor):

The semi-autonomous Danish territory, which has 82% of its surface covered in ice, lost 197 billion metric tons of ice in July, Ruth Mottram, a climate scientist with the Danish Meteorological Institute (DMI), tweeted Friday.

That’s about four times the 60-70 billion metric tons the DMI would normally expect to lose in July, Mottram added.

The melt comes as the record-setting heat wave in Europe moved over the Arctic island, forming a dome of warmth over the world’s second-largest ice sheet.

Martin Stendel, another DMI researcher, noted that the melt from just the last two days of July amounts to the equivalent of nearly 5 inches of water covering the entire state of Florida.

Mark Serreze, the director of the Snow and Ice Data Center in Boulder, Colorado, told The Associated Press that this year marks the island’s second-biggest melt area since 1981, when researchers started keeping such records. 2012 still has the record with nearly 90% of the island’s ice affected, but there’s still a month left in Greenland’s 2019 melt season.

Petteri Taalas, the secretary-general of the World Meteorological Organization issued a firm statement about this melt’s significance.

“This is not science fiction,” he said. “It is the reality of climate change. It is happening now and it will worsen in the future without urgent climate action.”

From The Monthly (Joëlle Gergis):

The terrible truth of climate change: The latest science is alarming, even for climate scientists

As one of the dozen or so Australian lead authors on the United Nations Intergovernmental Panel on Climate Change’s (IPCC) sixth assessment report, currently underway, I have a deep appreciation of the speed and severity of climate change unfolding across the planet. Last year I was also appointed as one of the scientific advisers to the Climate Council, Australia’s leading independent body providing expert advice to the public on climate science and policy. In short, I am in the confronting position of being one of the few Australians who sees the terrifying reality of the climate crisis.

Preparing for this talk I experienced something gut-wrenching. It was the realisation that there is now nowhere to hide from the terrible truth…

The results coming out of the climate science community at the moment are, even for experts, similarly alarming.

One common metric used to investigate the effects of global warming is known as “equilibrium climate sensitivity”, defined as the full amount of global surface warming that will eventually occur in response to a doubling of atmospheric CO2 concentrations compared to pre-industrial times. It’s sometimes referred to as the holy grail of climate science because it helps quantify the specific risks posed to human society as the planet continues to warm.

We know that CO2 concentrations have risen from pre-industrial levels of 280 parts per million (ppm) to approximately 410 ppm today, the highest recorded in at least three million years. Without major mitigation efforts, we are likely to reach 560 ppm by around 2060.

When the IPCC’s fifth assessment report was published in 2013, it estimated that such a doubling of CO2 was likely to produce warming within the range of 1.5 to 4.5°C as the Earth reaches a new equilibrium. However, preliminary estimates calculated from the latest global climate models (being used in the current IPCC assessment, due out in 2021) are far higher than with the previous generation of models. Early reports are predicting that a doubling of CO2 may in fact produce between 2.8 and 5.8°C of warming. Incredibly, at least eight of the latest models produced by leading research centres in the United States, the United Kingdom, Canada and France are showing climate sensitivity of 5°C or warmer.

When these results were first released at a climate modelling workshop in March this year, a flurry of panicked emails from my IPCC colleagues flooded my inbox. What if the models are right? Has the Earth already crossed some kind of tipping point? Are we experiencing abrupt climate change right now?

The model runs aren’t all available yet, but when many of the most advanced models in the world are independently reproducing the same disturbing results, it’s hard not to worry.

When the UN’s Paris Agreement was adopted in December 2015, it defined a specific goal: to keep global warming to well below 2°C and as close as possible to 1.5°C above pre-industrial levels (defined as the climate conditions experienced during the 1850–1900 period). While admirable in intent, the agreement did not impose legally binding limits on signatory nations and contained no enforcement mechanisms. Instead, each country committed to publicly disclosed Nationally Determined Contributions (NDCs) to reduce emissions. In essence, it is up to each nation to act in the public interest.

Even achieving the most ambitious goal of 1.5°C will see the further destruction of between 70 and 90 per cent of reef-building corals compared to today, according to the IPCC’s “Special Report on Global Warming of 1.5°C”, released last October. With 2°C of warming, a staggering 99 per cent of tropical coral reefs disappear. An entire component of the Earth’s biosphere – our planetary life support system – would be eliminated. The knock-on effects on the 25 per cent of all marine life that depends on coral reefs would be profound and immeasurable.

So how is the Paris Agreement actually panning out?

In 2017, we reached 1°C of warming above global pre-industrial conditions. According to the UN Environment Programme’s “Emissions Gap Report”, released in November 2018, current unconditional NDCs will see global average temperature rise by 2.9 to 3.4°C above pre-industrial levels by the end of this century.

To restrict warming to 2°C above pre-industrial levels, the world needs to triple its current emission reduction pledges. If that’s not bad enough, to restrict global warming to 1.5°C, global ambition needs to increase fivefold.

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