Permafrost at outposts in the Canadian Arctic is thawing 70 years earlier than predicted, an expedition has discovered, in the latest sign that the global climate crisis is accelerating even faster than scientists had feared.
A team from the University of Alaska Fairbanks said they were astounded by how quickly a succession of unusually hot summers had destabilised the upper layers of giant subterranean ice blocks that had been frozen solid for millennia.
“What we saw was amazing,” Vladimir Romanovsky, a professor of geophysics at the university, told Reuters. “It’s an indication that the climate is now warmer than at any time in the last 5,000 or more years.“
Canada warming at twice the global rate, climate report finds
With governments meeting in Bonn this week to try to ratchet up ambitions in United Nations climate negotiations, the team’s findings, published on 10 June in Geophysical Research Letters, offered a further sign of a growing climate emergency.
The paper was based on data Romanovsky and his colleagues had been analysing since their last expedition to the area in 2016. The team used a modified propeller plane to visit exceptionally remote sites, including an abandoned cold war-era radar base more than 300km from the nearest human settlement.
Diving through a lucky break in the clouds, Romanovsky and his colleagues said they were confronted with a landscape that was unrecognisable from the pristine Arctic terrain they had encountered during initial visits a decade or so earlier.
The vista had dissolved into an undulating sea of hummocks – waist-high depressions and ponds known as thermokarst. Vegetation, once sparse, had begun to flourish in the shelter provided from the constant wind.
Torn between professional excitement and foreboding, Romanovsky said the scene had reminded him of the aftermath of a bombardment.
“It’s a canary in the coalmine,” said Louise Farquharson, a postdoctoral researcher and co-author of the study. “It’s very likely that this phenomenon is affecting a much more extensive region and that’s what we’re going to look at next.“
Scientists are concerned about the stability of permafrost because of the risk that rapid thawing could release vast quantities of heat-trapping gases, unleashing a feedback loop that would in turn fuel even faster temperature rises.
The end of the Arctic as we know it
Even if current commitments to cut emissions under the 2015 Paris agreement are implemented, the world is still far from averting the risk that these kinds of feedback loops will trigger runaway warming, according to models used by the UN-backed Intergovernmental Panel on Climate Change.
With scientists warning that sharply higher temperatures would devastate the global south and threaten the viability of industrial civilisation in the northern hemisphere, campaigners said the new paper reinforced the imperative to cut emissions.
“Thawing permafrost is one of the tipping points for climate breakdown and it’s happening before our very eyes,” said Jennifer Morgan, executive director of Greenpeace International. “This premature thawing is another clear signal that we must decarbonise our economies, and immediately.”
As the crisis escalates…
… in our natural world, we refuse to turn away from the climate catastrophe and species extinction. For The Guardian, reporting on the environment is a priority. We give reporting on climate, nature and pollution the prominence it deserves, stories which often go unreported by others in the media. At this pivotal time for our species and our planet, we are determined to inform readers about threats, consequences and solutions based on scientific facts, not political prejudice or business interests.
More people are reading and supporting The Guardian’s independent, investigative journalism than ever before. And unlike many news organisations, we have chosen an approach that allows us to keep our journalism accessible to all, regardless of where they live or what they can afford. But we need your ongoing support to keep working as we do.
The Guardian will engage with the most critical issues of our time – from the escalating climate catastrophe to widespread inequality to the influence of big tech on our lives. At a time when factual information is a necessity, we believe that each of us, around the world, deserves access to accurate reporting with integrity at its heart.
Our editorial independence means we set our own agenda and voice our own opinions. Guardian journalism is free from commercial and political bias and not influenced by billionaire owners or shareholders. This means we can give a voice to those less heard, explore where others turn away, and rigorously challenge those in power.
In the Canadian Arctic, layers of permafrost that scientists expected to remain frozen for at least 70 years have already begun thawing. The once-frozen surface is now sinking and dotted with melt ponds and from above looks a bit like Swiss cheese, satellite images reveal.
“We were astounded that this system responded so quickly to the higher air temperatures,” said Louise Farquharson, a co-author of the study and postdoctoral fellow at the Permafrost Laboratory at the University of Alaska Fairbanks.
Permafrost is ground that remains frozen for at least two years. It underlies about 15% of the unglaciated Northern Hemisphere and serves a critical role in the transfer of carbon from living things to the atmosphere, Farquharson said. [Photos: Perfectly Preserved Baby Horse Unearthed in Permafrost]
The researchers recorded permafrost thawing to depths that were not expected until air temperatures reached levels the Intergovernmental Panel on Climate Change has predicted will occur after 2090, according to one of its “moderate” climate change models. The IPCC, which is a body of the United Nations, provides scientific information to help guide countries’ climate policies.
The researchers believe higher summer temperatures, low levels of insulating vegetation and the presence of ground ice near the surface contributed to the exceptionally rapid and deep thawing.
The most striking evidence is visible to the naked eye. As upper layers of permafrost thaw and ice melts, the land settles unevenly, forming what is known as thermokarst topography. Landscapes in the Canadian Arctic that had been defined by gently rolling hills are now pockmarked with ditches and small ponds. The ground at the northernmost study site sank by about 35 inches (90 centimeters) over the course of the study.
“We had this flat terrain when we started monitoring,” Farquharson told Live Science. “In 10 or so years, we saw the landscape transform.”
Their data allowed the researchers to interpret the topographical changes happening before their eyes.
“We were able to tie together air temperature and ground temperature with the formation of this thermokarst terrain,” Farquharson said.
The thawing has climatic implications for the globe and immediate ecological ramifications for the region. Thawing caused by higher air temperatures threatens to exacerbate global climate change.
“Permafrost is like a giant freezer that contains a lot of really delicious plant material and organics that aren’t being decomposed by microbes,” Farquharson said. “Thawing opens the freezer door” and allows the microbes to start converting that organic material into CO2.
In changing the physical makeup of the landscape, thermokarst also affects local ecosystems and waterways by inviting new plant growth, disrupting stable nutrient cycles and allowing for the sedimentation of streams and possibly coastal systems.
Determining the extent of new thermokarst development is difficult, but there is little doubt the problem is widespread. Farquharson and her team guess that about 231,000 square miles (600,000 square kilometers) of permafrost, or about 5.5% of the zone that is permafrost year-round, is vulnerable to rapid surface thawing.