Flash droughts are a type of extreme event distinguished by rapid intensification of drought conditions with severe impacts. They unfold on subseasonal to seasonal timescales (weeks to months), presenting a new challenge for improving predictions of when flash droughts occur.
In new research published in the March 2 edition of Nature Climate Change, a multi-institutional collaboration including Lawrence Livermore National Laboratory (LLNL) climate scientist Celine Bonfils, explored current understanding of the physical processes that can drive flash droughts, the existing capabilities to predict them and what is needed to make progress to establish effective early warning of flash droughts.
“There is a growing awareness that flash droughts can trigger severe agricultural impacts while the mechanisms at their origin need more investigation. This makes flash droughts a compelling frontier for research, monitoring and prediction,” Bonfils said.
Drought is perhaps the most complex and least understood of all weather and climate extremes. Despite an increasing drought risk in a future warmer climate, this risk is often underestimated and continues to remain a “hidden hazard.” Drought can span timescales from a few weeks to decades, and areas from a few kilometers to entire regions. Impacts usually develop slowly, are often indirect and can linger for long after the end of the drought itself.
“A better understanding of the physical processes leading to different types of droughts and how they affect societal and environmental vulnerability is more important than ever,” Bonfils said.
The impact of droughts arise in part from their long duration, such as the Dust Bowl and the 2011-2015 California drought, and have formed strong imagery in the U.S. Megadroughts lasting more than 20 years also have been documented in tree-ring records.
While plenty of research has been done on long-term droughts, not as much has been conducted on the rapid development, in the space of a few weeks, that sometimes occurs.
One flash drought that brought attention to the phenomenon occurred in the Midwest in 2012. The extent of abnormally dry conditions expanded from 30 percent of the continental United States in May 2012 to more than 60 percent by August. This event had significant impacts for agriculture and water-borne transportation in the region. The widespread impacts of the 2012 event caught the attention of the U.S. public and leaders.
But flash drought is not confined to the U.S. Processes that can produce flash droughts are the focus of research in China. In southern Queensland, Australia, a flash drought in early 2018 de-vegetated the landscape and drove livestock numbers to their lowest level in a century, a significant impact for agriculture.
“A drought monitoring and early-warning system is the foundation of effective, proactive drought policy, because it enables notice of potential and impending drought conditions,” said Angeline Pendergrass, a scientist at the National Center for Atmospheric Research and lead author of the paper.
An ideal early warning system would identify climate and water-resource trends and detect the emergence or probability of occurrence of a flash drought, as well as the likely severity of droughts and their impacts.
“Reliable information must be communicated in a timely manner to water and land managers, policy makers and the public through appropriate communication channels, to trigger actions documented in a drought plan, which is particularly critical for flash droughts,” the authors said. “That information, if used effectively, can form the basis for reducing vulnerability and improving mitigation and response capacities of people and systems at risk.”
From the Center for Colorado River Studies (Jian Wang and David E. Rosenberg):
Future consumptive water use is difficult to predict because underlying factors that influence consumptive use—future population growth, irrigation technology and practices, climate, agricultural commodity prices and other factors—are individually difficult to forecast. Future consumptive water use cannot be forecast as a point value within a range, nor with probabilities. Instead, future consumptive water use can only be authentically described using a set of scenarios that represent possible future conditions.
Since the 1980s, Bureau of Reclamation and the Upper Colorado River Commission have developed many scenarios of possible future consumptive use for the Upper Colorado River basin (Figure 1, dashed colored lines). Each scenario describes one possible trajectory of future consumptive water use out to the year 2040, 2050, and 2060. When averaged over the long term, each scenario of future consumptive use over-estimated the observed consumptive use reported by Bureau of Reclamation in its regular Colorado River Consumptive Use and Loss Reports (Figure 1, solid black line). Many other water systems also consistently overestimate their demands (Heberger, 2016; Kindler and Russell, 1984). Additionally, the trace of observed use has many more year-to-year variations due to changing precipitation and out-of-basin exports than the forecast scenarios. The disparity between the scenarios of possible future consumptive use and observed use show the inherent difficulties and uncertainties to estimate future demands and develop scenarios that span all possible future conditions. Thus, it is better to develop more scenarios to cover a wider range of future conditions. However, including more scenarios also increases the computational burden of analysis.
The EPA is involved in multiple PFAS-related criminal investigations, the agency said Wednesday, adding another knot to an already complex legal landscape for “forever chemicals.”
The Environmental Protection Agency acknowledged the probes in a new progress report on its 2019 PFAS Action Plan. The document says the agency “has multiple criminal investigations underway concerning PFAS-related pollution.”
EPA Administrator Andrew Wheeler told Bloomberg Law the agency is committed to using all its enforcement authorities to address contamination.
“We do use all of our enforcement tools, so if it’s warranted for criminal, we would certainly look to do that,” he said after a National Association of State Department’s of Agriculture event in Arlington, Va.
Wheeler declined to give further detail, saying he couldn’t comment on pending investigations. Federal criminal investigations and related files are confidential.
“Multiple investigations clearly signals EPA is serious about understanding what the manufacturers knew about the chemicals’ toxicity and when they knew it,” said Earth & Water Law Group founder Brent Fewell, an EPA official during the George W. Bush administration. “EPA is likely focused on whether the PFAS manufacturers knowingly failed to disclose to EPA the known risks of the chemical.”
“It’s not at all surprising,” he added, “that EPA has signaled a criminal investigation or even multiple investigations into PFAS given the heightened health concerns and public attention.”
In case you forgot, Colorado State University is a land-grant institution, originally formed as an agricultural college.
To further the University’s initial mission, the College of Agricultural Sciences and the College of Veterinary Medicine and Biomedical Sciences are teaming up to start the Sustainable Livestock Systems Collaborative.
“I think the impetus really is that, you know, CSU is a land-grant university,” said Mark Zabel, CVMBS associate dean for research. “We still have a commitment to agriculture and to educating Coloradans centered around those issues.”
Zabel said that while there will be no physical building or presence, the Sustainable Livestock Systems Collaborative will be a collection of stakeholders — researchers, policy makers and producers in the livestock, agriculture and dairy industries — coming together around the idea of sustainable farming practices.
“The overall goal (is) to specifically engage with livestock production and to help producers at the grassroots (level) address firstly profitability, secondly their environmental footprint, thirdly animal health and lastly human health, particularly via food safety,” said Keith Belk, head of the department of animal sciences and co-chair of the steering committee.
Applications for director of the initiative recently closed, Belk said, and research is anticipated to begin by the fall semester of this year. Belk said they will be opening a couple more faculty positions in the coming months as well.
James Pritchett, interim dean of CAS, said professionals in the agriculture industry have been coming to CSU asking for answers to questions grounded in sustainability. The driving force behind much of the research conducted by the collaborative will be issues posed to CSU by those professionals.
“For example, as the climate changes and we have disrupted weather patterns and we have periods of drought or flood, how does that affect how we can grow crops?” Zabel asked. “We can do things like try to develop heartier strains of grain that can survive droughts or that can survive floods. We can develop better feeding and watering practices for our livestock.”
Belk added that research could be anything related to the environmental impact of farming, ranching and livestock production. Water use, water contamination, soil erosion, land management and production of greenhouse gases are all topics the collaborative wants to explore and find solutions to.
The collaborative will not only provide faculty with more opportunities to conduct research, but will allow for undergraduate and graduate students to participate as well.
“I am very committed to having all of our students — at every education level — coming together as research teams to solve these problems,” Zabel said. “In (the department of microbiology, immunology and pathology), we really emphasize undergraduate research. It’s our goal to be able to train each of our undergraduates in long-term substantive research experience.”
Pritchett said funding for the collaborative comes from repurposing a base budget that funded faculty members who have since retired or moved on, and the Office of the Provost will then match that with funding from student allocations from the general fund.
“We’re going to do some of the very best science to help create sustainable food systems,” Pritchett said. “It’s reaching across not just the college of agriculture or vet med, it’s actually across our entire campus. Where we have students interested in sustainability, we’ve got scientists that are interested in it, and we’re going to be able to do great things by working together.”
Serena Bettis can be reached at email@example.com or on Twitter @serenaroseb.
A bill aimed at expanding Colorado’s instream-flow loan program is moving through the state legislature and has support from agricultural water users, Front Range water providers and environmental organizations, in contrast to last year when the bill ran into opposition.
House Bill 1157 [Loaned Water For Instream Flows To Improve Environment], which last week passed the House in a unanimous 60-0 vote, would allow water-rights holders to temporarily loan their water to the Colorado Water Conservation Board’s instream-flow program with the goal of improving the natural environment.
The bill expands the number of years from three to five (but for no more than three consecutive years) that a loan may be exercised within a 10-year period. The loan also may be renewed for two additional 10-year periods, meaning that holders of agricultural water rights could theoretically loan their water for the benefit of the environment for 15 of 30 years.
Environmental groups, including The Nature Conservancy, Colorado Sierra Club and Conservation Colorado, support the legislation, and so do water-user organizations, including the Colorado Water Congress, Denver Water, Northern Water, and the Grand Valley Water Users Association.
HB 1157 is sponsored by Sen. Kerry Donovan (D-Vail) and District 26 Rep. Dylan Roberts (D-Avon), both of whom floated a similar bill last year. This year’s iteration gained the sponsorship of District 57 Rep. Perry Will (R-New Castle).
After the bill faltered in last year’s legislative session, Roberts knew he had some work to do before he brought it back to lawmakers, so he spent the summer and fall talking with the many interested parties about how to improve it.
“I represent Eagle and Routt counties, which are home to four major river systems, and I know how vital it is to the Roaring Fork Valley, the Eagle River Valley and the Yampa River Valley to have a really strong flowing river,” he said.
The Eagle, Colorado and Roaring Fork rivers flow through Eagle County, and the Yampa River flows through Routt County.
“Instream-flow loans allow people to loan the water back and help the river, while not losing their water rights,” Roberts said.
n the new bill, lawmakers added more protections for water-rights holders by increasing the window for people to appeal a loan. The legislation quadruples the comment period from 15 to 60 days so that those who feel they could be harmed by a loan of water have sufficient time to raise their concerns with the state engineer
Instream flow program
Colorado’s instream-flow program gives the CWCB the ability to hold water rights specifically for preserving the natural environment “to a reasonable degree” by keeping water flowing in the river. Since 1973, the CWCB has appropriated instream-flow rights on nearly 1,700 stream segments, covering more than 9,700 stream miles.
Instream water rights are administered under Colorado’s prior appropriation system. And, given that none of the instream rights were in place before 1973, most of them are junior to senior agricultural water rights. Those rights, which can date to the 1860s in Colorado, have a higher priority under the “first in time, first in right” doctrine.
Senior ag rights divert significant amounts of water from the state’s rivers and streams and can even dry up some reaches in drought years. However, the state’s instream-flow program does allow owners of such senior water rights not to use their rights for irrigation and instead leave their irrigation water in the river, on a temporary basis, to bolster low flows. And the new legislation expands that option.
The temporary loan program — where water-rights owners offer, in exchange for payment, to contribute their water to one of these segments with an existing instream-flow right — has only been used seven times since its creation in 2003. In Division 5, temporary water loans have occurred on Deep Creek, the Fraser River and the Colorado River.
CWCB officials estimate an additional two to four loans under the program over the next few years.
In past deals, irrigators have been paid for the loan of their water by the state, Trout Unlimited or the Colorado Water Trust.
According to CWCB Stream and Lake Protection section chief Linda Bassi, the loan program can help boost streams in late summer when flows are low, temperatures are high and fish are stressed.
“It’s a really helpful tool for instream flows that fall short,” she said. “It’s always good to have more tools to help preserve the environment.”
River District support
The bill has garnered the support of the Glenwood Springs-based Colorado River Water Conservation District, which helped shape the revamped 2020 bill with its input. The River District board voted unanimously to support the measure, according to Zane Kessler, director of government relations.
“Rep. Roberts went above and beyond to make sure the bill addressed the River District’s needs and provides meaningful protections to our constituents on the West Slope and agricultural water users across the state,” Kessler said.
Also, the legislation requires the CWCB to give preference to loans of water stored in reservoirs, when available, over agricultural and other water rights diverted directly from rivers and streams. This provision was included at the request of the River District.
Kirsten Kurath, attorney for the Grand Valley Water Users Association, said lawmakers worked with the association over the past year to improve the bill from 2019.
“I think, in general, that the bill is much more protective now of other water-rights users on the stream,” Kurath said.
The bill is now under consideration by the state Senate.
Aspen Journalism collaborates with The Aspen Times and other Swift Communications newspapers on coverage of water and rivers. This story ran in the Feb. 29 issue of The Aspen Times.
FromThe High Country News, February 19, 2020 (J. Madeleine Nash):
Like a giant dragonfly, the chopper skims over undulating swaths of tussocky tundra, then touches down at Wolverine Lake, one of a swarm of kettle lakes near the Toolik Field Station on Alaska’s North Slope. Even before the blades stop spinning, Rose Cory, an aquatic geochemist from the University of Michigan in Ann Arbor, gracefully swings to the ground and beelines to the spot where, four years ago, a subterranean block of ice began to melt, causing the steep, sloping bank to slump into the water. The lake throws back a somber reflection of the clouds swirling above, its surface riffled by the wind.
Cory has brought me here because the slump provides a vivid example of the ordinarily inaccessible stuff she studies. Slick with meltwater, the chocolaty goop brims with microscopic bits of once-living things that have not touched sunlight or air or flowing water for centuries, perhaps millennia. Deeper still lie plant and animal remains that could be tens of thousands of years old, dating back to the Pleistocene, when steppe bison and woolly mammoths wandered a treeless region that extended from here across the Bering Land Bridge, all the way to Siberia.
For a moment we just stand there, staring down at the raw gash. Occasionally, Cory lifts her head to scan the shoreline for furry visitors. Despite our proximity to the field station, we are in a wild place, without roads or trails or protective shelter. For years, in fact, the lake was known to researchers only by a number. It earned its moniker in 2013, when a hardy trio of young researchers hauled their instruments nearly five miles cross-country to measure the just-discovered slump and spotted a wolverine circling a wounded caribou.
Cradled by cloudberry, dwarf birch and willow, Wolverine Lake crouches in the shadow of the snow-streaked Brooks Range. A bit over a third of a mile across, it formed during the retreat of a giant lobe of ice that, 60,000 years ago, advanced from its stronghold in those looming mountains to fill the valley of the Sagavanirktok River — commonly called “the Sag” — into which the lake’s outlet stream now drains. The irregular shoreline still traces out the shape of the marooned ice fragment that molded the bowl-like basin. The buried ice that triggered the slump is yet another relict of this long-vanished world, as are the glacier-ground rock and organic debris now streaming into the water.
To those like Cory who know how to parse it, this slump is a source of wonder. It offers a tantalizing portal into the hidden world of permafrost, the broad band of perpetually frozen soils that undergirds a circumpolar region more than twice the size of the continental U.S. This region is now warming at twice the rate of the global average, with grave implications for the stability of permafrost and all it holds. Both small and large things are poised to emerge from this gelid domain, from common soil-dwelling bacteria, to the nearly intact carcasses of Ice Age megafauna. The most important, however, is the carbon stored in the frozen layers of leaves, stems and roots that lie beneath our feet.
“Think of a cup of tea,” Cory suggests. The carbon-rich organic materials the slump is carrying into the lake are too small to be removed with a filter, but substantial enough to impart a tinge of color and even flavor. The water samples collected from the lakes, streams and rivers here indicate that the brew percolating out of freshly exposed permafrost differs sharply from the steep that comes from shallow layers of soil that thaw and refreeze in accordance with the natural cycle of seasons.
At first, this might seem little more than a bit of esoterica to tuck away for a trivia exchange in the Toolik dining hall. Yet discerning permafrost’s protean signature is one of the keys to understanding what this vast landscape’s transformation might mean — not just for the Arctic, but for the whole planet. The research Cory conducts on a meticulous, molecular scale is just part of a larger body of work aimed at answering an increasingly critical question. Globally, the frigid soils of the Far North store almost double the amount of carbon already circulating in the atmosphere in the form of heat-trapping carbon dioxide — enough to drive the climate system into territory Earth has not experienced for millions of years.
But carbon travels an invisible highway with multiple on- and off-ramps, some of which lead into the atmosphere, some away from it. Figuring out all of this entails an excruciatingly complicated set of calculations. In order to plug in the numbers, scientists like Cory must first understand the biological and chemical processes that control the routes carbon takes through soils and surface waters. As the preserved past thaws and begins to decay, Cory wonders, just how much of that carbon will end up in the atmosphere? And how fast?
To peek at permafrost from below, I toured the “permafrost tunnel” bored into a hillside outside Fairbanks, Alaska, by the Cold Regions Research and Engineering Laboratory of the U.S. Army Corps of Engineers. Kept at a chilly 25 degrees Fahrenheit, it exudes a smell reminiscent of garden dirt. There, embedded in a matrix of frozen silt, I could see the bones of mammoths, the horns of bison and the roots and leaves of sedges that grew here more than 30,000 years ago. I could also see rocks and gravels and dark wedges of ice glistening in the artificial light.
This hard, heterogeneous composite has long been a barrier to economic development in both the Arctic and sub-Arctic. The gold miners who flocked to the Alaskan and Canadian Yukon hoping to make their fortune around the turn of the 20th century had to use wood fires, hot water and steam to thaw the gold-bearing gravels. “As resistant to excavation as a mass of reinforced concrete,” the general manager of one mining company complained, though the difficulty didn’t stop it from buying up and working a number of placer claims.
Yet as the slump at Wolverine Lake illustrates, permafrost has a geophysical Achilles’ heel. Once subsurface temperatures creep above freezing, the ice it contains melts and flows away. In the uplands, as around Wolverine Lake, this ice is often a glacial legacy. Elsewhere it comes from rain and snowmelt that have gradually worked their way down through a network of surface cracks and refrozen. Some sections of permafrost contain the merest flecks of ice, barely enough to moisten thawing soils; others are larded with massive wedges that can measure 10 or more feet across.
Until recently, worries about the stability of permafrost focused on the more southerly boreal zone. But geophysicist Vladimir Romanovsky, head of the Permafrost Laboratory at the University of Alaska Fairbanks Geophysical Institute, has grown increasingly concerned about the permafrost on Alaska’s cold North Slope. For four decades now, the lab has tracked permafrost temperatures in a network of deep holes that field crews have drilled across the region. Beginning in 1988, Romanovsky notes, temperatures in the northernmost holes started to rise, echoing the rise in air temperatures. Readings taken near Prudhoe Bay show that the permafrost there has now warmed by more than 5 degrees Fahrenheit at a depth of 65 feet and by 9 degrees Fahrenheit at a depth of 3 feet, where temperatures are now in the 20s. If the trend continues, Romanovsky says, the permafrost close to the surface could reach the thawing point by 2050.
Even today, ice-rich permafrost can grow warm enough to lose its structural integrity. Almost anything that insulates the ground and blocks the flow of cold winter air can do it: a road, a building, a big pile of snow. So can the destruction of vegetation, which shades soils from the summer sun. In 2007, an intense North Slope tundra fire stripped the landscape bare, creating a new landmark, the Valley of Thermokarsts. (“Thermokarst” is the technical term for thaw slumps and related phenomena. Typically, karst topography, riddled with sinkholes and caves, comes from rain and snowmelt that trickles into the ground, dissolving underlying layers of limestone. In the case of thermokarst, water from ice melted by heat provides the erosive force.)
Areas adjacent to sun-warmed bodies of water — coastal bluffs, the banks of rivers and lakes — are prone to thermokarst, especially when undermined by floods or the persistent action of waves. In Alaska, the first recorded sighting of a thermokarst event in progress comes from a 19th century voyage along the Alaskan coast made by Otto von Kotzebue, a lieutenant in the Russian Imperial Navy. At one landing site, he and his party came across “masses of … ice, of the height of a hundred feet, which are under a cover of moss and grass. … The place which, by some accident, had fallen in … melts away, and a good deal of water flows into the sea.”
Thaw slumps can occur in colder times — Kotzebue’s voyage took place towards the end of the centuries-long cold snap known as the Little Ice Age — but they are more likely to occur in balmy interludes. In 2005, a thaw-triggered landslide near Toolik hit another lake known to scientists only as N14. It charged the water with so much glacier-ground rock that the color “went from clear to milky blue,” recalls Feng Sheng Hu, a paleoecologist at the University of Illinois at Urbana-Champaign. The same rock flour showed up as distinct deposits in the 6 feet of cored sediments Hu and his colleagues obtained from the deepest part of the lake. The sediments yielded a thermokarst record that covers the past 6,000 years. Of 10 large slumps that occurred over that time span, seven coincided with climatic intervals marked by warmer summers.
Thermokarst events are the “high-speed trains of permafrost thaw,” observes Cory’s colleague, University of Michigan ecologist George Kling, and there are suggestions they may be increasing. In 2008, an aerial census around Toolik counted nearly three dozen within a 230-square-mile area. Two-thirds did not exist prior to 1980. How many of these might have occurred without the profligate burning of fossil fuels is hard to gauge, but in the future, according to an international team of scientists, an estimated 20 percent of the area underlain by permafrost may become vulnerable to thaw-driven collapse as gears in the climate system continue to shift, ratcheting Arctic temperatures ever higher.
For a sense of how permafrost shapes Alaska’s northern reaches, you might drive to Toolik from Fairbanks, heading out on the Elliott Highway to Livengood, then turning north onto the Dalton Highway. This is the legendary Haul Road, the rough two-lane trucking corridor that parallels the flow of crude oil from the North Slope through the Trans-Alaska Pipeline to the tanker terminal at Port Valdez. The route roller-coasters through some of the state’s most scenic country. It is treacherous, with steep curves, virtually no guardrails, and, in places, a slalom course of thaw-triggered potholes.
For the first part of the journey, the Haul Road slices through the boreal forest of the cold, dry Alaskan interior. Here, the permafrost is disconnected, creating a subtle mosaic in the form of alternating stands of black and white spruce. White spruce mark the warmer, better-drained slopes that are often permafrost free, while black spruce — funny little trees that look like dark green bottle brushes — sink their roots into the cold, soggy soils above an impermeable layer of frozen ground. After you cross the Arctic Circle and head into the Brooks Range, the trees become sparser and scragglier, then disappear.
Beneath the tundra of the North Slope, permafrost forms a continuous underlayment, extending from the Brooks Range to the edge of the Arctic Ocean. At Toolik, this icy substrate is 600 feet thick from top to bottom, compared to 150 feet in the boreal zone. Farther north, beneath the Arctic Coastal Plain, it extends to depths of 2,000 feet.
Throughout this vast realm of frozen soil, thermokarst serves as a source of ecological disturbance and renewal. On steep terrain it causes landslides, bulldozing new clearings and replenishing the nutrients in waterways. (Along with carbon, permafrost also contains nitrogen, phosphorus and calcium.) On the flat, it creates depressions that evolve into ponds, lakes and wetlands. In the boreal zone, along the Tanana River, successive episodes of thermokarst are now converting a birch forest into bogland. Thermokarst is impacting the built landscape as well. In Alaska, one of the most serious impacts of climate change will be the billions of dollars in damage, already extensive, that thermal erosion deals to infrastructure.
But until warmth awakens it, permafrost remains inert. The biological and chemical action takes place in the layer of seasonally thawed soil above it, the “active layer,” as it’s called. This is where the root zone is, where microorganisms live, where rain and snow melt circulate, blocked from following pathways that would lead to deeper drainage. Along with the chilly air, which stymies evaporation, the impermeability of permafrost is the reason the Far North can be so dry — Prudhoe Bay gets less precipitation than Phoenix, Arizona — and yet so water-logged.
A stunning example can be glimpsed from a bush plane flying northwest of Toolik, along the coastal plain. Everywhere, it seems, water puddles on the surface in geometric arrays. It twists and turns in sinuous ribbons. It collects in lakes that look like daubs of sky brushed across the tundra. These are the famous “thaw lakes,” scooped out of the permafrost by thermokarst. Many are too shallow to sustain fish, but nonetheless help support hundreds of thousands of migratory waterfowl and shorebirds, including Brant geese, king eiders and buff-breasted sandpipers.
This is a dynamic landscape, one highly responsive to climate change. Already the loss of ice along the coast is exposing the outer fringe of lakes and wetlands to seawater intrusion. In response, plants adapted to wet tundra are giving way to salt-tolerant species. Eventually, rising temperatures may combine with higher precipitation to cause a more rapid cycle of lake formation and decay. In 2014, one thaw lake swollen with rain and snowmelt breached its permafrost-armored banks and drained in the space of just 36 hours.
The aquatic environments of the Arctic are not just ecologically important; they are climatologically significant as well. Over 40 percent of the carbon dioxide currently entering the atmosphere from the Arctic comes from its surface waters. The reason is simple: In addition to the carbon-rich detritus thrown off by algae and other aquatic organisms, Arctic lakes, rivers and streams also receive generous infusions of soil carbon that seeps into their waters from the active layer above the permafrost. As permafrost thaws, its carbon will also enter the hydrologic system, becoming an increasingly important part of the emissions stream.
But a carbon molecule drifting through water doesn’t magically throw off carbon dioxide (or methane, a less common but even more potent greenhouse gas.) First, it must be broken down, most often by microbes that remain metabolically active year round. One of the curiosities around Toolik is the sudden release of CO2 that occurs each spring when the ice covering its lakes breaks up. This short-lived event is a bit like uncapping a soda bottle, without the audible fizz. It’s due to the fact that, under the ice, microbes have been busy consuming carbon-rich molecules, exhaling carbon dioxide as a byproduct.
The addition of permafrost carbon to soils and surface waters adds a new layer of complexity. Not long ago, much of this carbon — dissolved organic carbon or “dead old carbon,” as Rose Cory calls it — was thought to be structurally so complex that it would take a long time for microbes to process it. Instead, Cory and her colleagues are finding, these tiny organisms lustily respond to fresh infusions of permafrost carbon, attacking tasty morsels with enzymes like nanoscale ninjas hurling dagger-sharp stars.
The Toolik Field Station, a compact jumble of pre-fab structures, straddles a site that once housed construction crews for the Trans-Alaska Pipeline. Operated by the University of Alaska Fairbanks and funded by the National Science Foundation, along with other government agencies, it has become a magnet for scientists involved in Arctic research. To avoid perturbing the permafrost, many of the buildings here are elevated above ground, as are long sections of the pipeline.
Climbing the steep staircase to Cory’s trailer lab, I find her huddled with her graduate students in front of a computer. She says it feels a bit serendipitous to find herself in a doublewide again. The shape and feel of the workspace evoke warm memories of the trailer in rural Montana that was her childhood home. “I loved it,” she says. “You know the old expression, ‘You can take the girl out of the trailer, but. …’ ” Everyone has just arrived, so the lab is a study in controlled clutter. This is where the team will spend hours doing tedious and painstaking analysis. Still unpacked are boxes of plastic bottles, which, over the summer, will be filled in the field with samples of water aswirl with carbon and brought here for study.
Now 42, Cory first set foot in Toolik 15 years ago when she herself was a student. Ever since, the arc of her career has tracked rising concern about the fate of permafrost and the carbon it contains. Trained in photochemistry, Cory often sees things others do not. Previously, for example, scientists thought mostly about the carbon dioxide released by microbes that, in soils, operate totally in the dark. But from the moment she arrived at Toolik, Cory saw a landscape awash in light. For a few months of the year, 24 hours a day, Arctic waters are quite literally sun-struck, which turns out to be relevant to the release of carbon from permafrost.
Starting in 2010, Cory linked up with Michigan’s George Kling and Byron Crump, a microbiologist from Oregon State University, to explore the biochemical and geochemical impacts of light. One set of experiments involved collecting water samples from seven active thermokarst sites. After removing impurities with a filter, the team put the samples into plastic pouches and left them outside to bask in the sun. This “sun tea” was then presented to bacteria sieved from the same thermokarst-infused water.
This sunlight treatment, the scientists found, substantially boosted the microbes’ ability to convert the dissolved carbon compounds in the samples into carbon dioxide. The mechanism? Light, ultraviolet light in particular, is a breaker of chemical bonds. Like a kitchen knife, it slices and dices organic molecules into smaller, more palatable bits. A second series of experiments focused on the microbial communities cultured from Arctic soils. Most effective at decomposing light-treated organic carbon were those that emerged from thawed chunks of permafrost where they’d remained dormant, or even — as some believe — sluggishly active for centuries.
But microbes are just part of the story. In a study of more than 70 lakes, streams and rivers, including the Sag, Cory and her colleagues have established that exposure to sunlight alone can turn carbon into CO2 without any microbial involvement. The rate at which this happens varies with the cloudiness of the sky, the thickness of the ice cover and the depth and clarity of the water. But on average, they found, this abiotic conversion may account for about a third of all the carbon dioxide currently released by Arctic surface waters. It’s a photochemical pathway that will increase in importance as rising temperatures accelerate the thawing of permafrost and the melting of sunlight-occluding ice.
Climate is only one factor that affects the rate at which carbon is wrested from organic material and released into the atmosphere. Another is molecular structure. Soil samples that Cory and a graduate student cored from the watershed of a major creek contained more than 2,500 different organic compounds. Twenty percent were found only in permafrost; 30 percent, only in the active layer, with the remainder common to both. The masses of these compounds are known, as are the identities of the atoms that compose them, but not the Tinkertoy-like configurations in which the atoms are arranged.
It’s a knowledge gap that bears directly on the question of how much additional carbon will end up in the atmosphere, and Cory and others are racing to fill it. Not all the carbon in permafrost will end up being converted to carbon dioxide. Some of it will be captured by sediments and swept by the Sag and other rivers into the carbon graveyard in the Arctic Ocean. Some of it will prove difficult for microbes and sunlight to break down. “Without knowing the structures of these compounds, it’s impossible to predict how many will get converted to carbon dioxide, and over what time scale,” Cory observes. “Is it five seconds or a thousand years?”
Leaving Cory’s lab, I head out on the network of boardwalks that lead from the field station to study sites scattered across miles of tundra. In one way or another, most of the scientists who work here are involved in tracking the changes rippling through this region. On either side of the boardwalk, fields of cotton grass prepare to carpet the landscape with silvery seed heads. What will this high-latitude ecosystem look like a century from now? Will cotton grass, Toolik’s signature plant, still grow here in such profusion?
The last time our planet confronted such a consequential upheaval was around 12,000 years ago, when the last Ice Age ended in a rolling thunder of warmth. On a geological time scale, the changes that followed were fast — sea levels rose, weather patterns changed, species migrated pole-ward — but measured against the lifetime of an itinerant hunter-gatherer, they would have been all but imperceptible. This time around, the rate of transformation and its impacts on our densely settled planet are becoming obvious within a generation, especially in the Far North, where air temperatures have been rising at a clip of 1 degree Fahrenheit per decade.
The natural world is now responding in ways that amplify that warming. Dwindling sea ice is changing the color of the Arctic Ocean, uncovering dark blue waters, which absorb solar heat rather than reflect it. The loss of ice is likewise exposing the permafrost-rich coastline, and the remote communities along it, to storms and frenzied waves. In the boreal zone, wildfires stimulated by record heat and drought have burned through millions of acres of trees and released the carbon once locked into wood; they have also turned thick layers of forest duff to ash, ripping away the summer insulation that once protected the permafrost.
The good news, says Northern Arizona University ecologist Ted Schuur, lead investigator for the Permafrost Carbon Network, is that a sudden, catastrophic release of CO2 from permafrost seems unlikely. The bad news is that a steady, incremental leak is plenty problematic on its own. Under the current warming trajectory, Schuur and his colleagues estimate, between 5 and 15 percent of the carbon stored in the Far North’s soils is likely to make it into the atmosphere by the start of the 22nd century.
This might not sound like much, but 15 percent is equal to the jump in atmospheric CO2 — from 280 to more than 400 parts per million (ppm) — that has occurred since the Industrial Revolution. To avoid courting danger, any additional rise in global mean temperature would wisely be kept below 2 degrees Fahrenheit, according to the Intergovernmental Panel on Climate Change (IPCC). That, in turn, means stabilizing carbon dioxide levels at 450 ppm, leaving little time to dawdle. This is why permafrost carbon is such a wild card. Even a modest release will complicate efforts to step back from the brink.
So new is this concern that the global climate models used by the IPCC have not yet factored in permafrost. Likewise, the permafrost models currently under development do not incorporate the potential for rapid, landscape-scale carbon release through thermokarst, which could cause projections to rise. But one thing is clear, says the Permafrost Carbon Network’s Schuur: By easing up on the pressure we’re placing on the climate system, we can reduce the potential for unpleasant surprises. “The more we push the system, the less control we have,” he says.
As I head back down the Haul Road, the questions that arose at Wolverine Lake seem more pressing than ever. Out the side window, I watch the pipeline track along its 800-mile journey. Late last year, in an attempt to keep the pipeline at full capacity, Alaskan Republican Sens. Lisa Murkowski and Dan Sullivan tacked onto the federal tax bill a provision that opens an ecological gem along the coast — the Arctic National Wildlife Refuge — to oil and natural gas exploitation. Signed into law by President Donald Trump, the bill revives a long-simmering controversy that pits economic interests against potentially enormous environmental costs.
Were it not for the pipeline, and the occasional 18-wheeler lumbering by, I would feel as though I were traveling through an exquisitely rendered scroll painting, marveling at timeless vistas of craggy peaks, rolling hills and jewel-like lakes. The sweep of the terrain invites a sense of permanence, as if things have always been this way, as if they will continue to be this way forever. And, yet beneath the surface, a geophysical dragon is stirring. A penumbra of clouds gathers above the pipeline, casting it into shadow.
Madeleine Nash is a San Francisco-based science writer who frequently covers climate issues. A former senior correspondent at Time Magazine, she is working on a book about climate change with her physicist-photographer husband, Thomas Nash (nashpix.com).
This coverage is supported by contributors to the High Country News Enterprise Journalism Fund.