Widespread permafrost degradation seen in high Arctic terrain


Share post:

Rapid changes in terrain are taking place in Canada’s high Arctic polar deserts due to increases in summer air temperatures.

Widespread permafrost degradation seen in high Arctic terrain
Due to record summer temperatures in recent years, high Arctic polar terrain is changing
[Credit: Melissa Ward Jones]

A McGill-led study published recently in Environmental Research Letters presents close to 30 years of aerial surveys and extensive ground mapping of the Eureka Sound Lowlands area of Ellesmere and Axel Heiberg Islands located at approximately 80 °N.

The research focuses on a particular landform (known as a retrogressive thaw slump) that develops as the ice within the permafrost melts and the land slips down in a horseshoe-shaped feature. The presence of these landforms is well documented in the low Arctic.

But due to the extremely cold climate in high Arctic polar deserts (where average annual ground and air temperatures are -16.5 °C/2.3 °F, and -19.7 °C /-3.46 °F, respectively), and the fact that the permafrost is over 500 metres (or about 1/3 of a mile) thick, it had been assumed this landscape was stable. But the McGill-led research team found that this has not been the case.

“Our study suggests that the warming climate in the high Arctic, and more specifically the increases in summer air temperatures that we have seen in recent years, are initiating widespread changes in the landscape,” says Melissa Ward Jones, the study’s lead author and a PhD candidate in McGill’s Department of Geography.

Widespread permafrost degradation seen in high Arctic terrain
Scientists from McGill University have been mapping the high Arctic polar deserts for almost thirty years. In the past
few years, as the permafrost melts, they have seen an increase and spread of landslide-like features in an area
where they had believed extremely cold temperatures would ensure the stability of the land
[Credit: Melissa Ward Jones]

The research team noted that:

– There has been a widespread development of retrogressive thaw slumps in high Arctic polar deserts over a short period, particularly during the unusually warm summers of 2011, 2012 and 2015;

– That the absence of vegetation and layers of organic soil in these polar deserts make permafrost in the area particularly vulnerable to increases in summer air temperatures;

– Despite its relatively short duration, the thaw season (which lasts for just 3-6 weeks a year) initially drives the development of slumps and their later expansion in size, as their headwall retreats; and

– Over a period of a few years after the initiation of slumps, study results suggest various factors related to terrain (e.g. slope) become more important than air temperature in maintaining active slumps.

In recent years, high summer temperatures have started melting the ice in the permafrost. 
As a result, land forms are changing unexpectedly [Credit: McGill University]

“Despite the cold polar desert conditions that characterize much of the high Arctic, this research clearly demonstrates the complex nature of ice-rich permafrost systems and climate-permafrost interaction,” adds Wayne Pollard, a professor in McGill’s Department of Geography and co-author on the study. “Furthermore, it raises concerns about the over simplification of some studies that generalize about the links between global warming and permafrost degradation.”

Author: Katherine Gombay | Source: McGill University [May 23, 2019]



Related articles

Preparing for the flood: Visualizations help communities plan for sea-level rise

Researchers at the University of British Columbia have produced computer visualizations of rising sea levels in a low-lying...

First direct evidence for mantle plume origin of Jurassic flood basalts in southern Africa

The origin of gigantic magma eruptions that led to global climatic crises and extinctions of species has remained...

Rare primate species needs habitat help to survive

The population of the critically endangered large primate known as the drill (Mandrillus leucophaeus) has been largely reduced...

New evidence that volcanism triggered the late Devonian extinction

The late Devonian extinction, about 370 million years ago, is one of the 'Big Five'. It killed up...

First tally of US-Russia polar bears finds a healthy population

Not all polar bears are in the same dire situation due to retreating sea ice, at least not...

Planting trees is no panacea for climate change, says ecologist

Restoration ecologist Karen Holl has a simple message for anyone who thinks planting 1 trillion trees will reverse...

Climatic stability resulted in the evolution of more bird species

More species of birds have accumulated in genera inhabiting climatically stable areas. This is shown by a new...

Global river deltas increasingly shaped by humans, study says

A new study of nearly every delta on the planet shows how river delta shapes and sizes around...