‘Abrupt thaw’ of permafrost would have an effect on climate change models
- by Brittany Mendoza
- in Research
- — Aug 23, 2018
The lakes are created when warming soil melts ground ice and causes the surface to collapse and form pools of water, according to the study. Water takes up less space than ice, so this leaves room for water to collect from other sources as well, including rain and snow.
A recent study produced by University of Alaska researcher Katey Walter Anthony and colleagues shows that permafrost is thawing much faster under lakes in Interior Alaska than predicted. Permafrost in terrestrial environments generally experiences shallow seasonal thawing over longer time spans. In the Arctic, ice-rich permafrost soils can be up to 260 feet (80 meters) thick.
But despite its name, permafrost is not always permanent.
And that's where the problems start.
The Northern Tundra stores possibly the largest natural reservoir of organic carbon on Earth, trapped in the frozen soil. These pools significantly speed up the thawing of the permafrost, which leads to food being available to microbes that consequently produce carbon dioxide and methane.
Abrupt thawing, says the space agency, happens below the surface of a specific type of Arctic lake called a thermokarst lake.
"You can't stop the release of carbon from these lakes once they form", Walter Anthony said.
As the Arctic warms, some of its lakes are bubbling. But this abrupt thawing might be worse than we originally thought, according to researchers from the USA and Germany.
Even in the scenario where humans reduce their global carbon emissions, large methane releases from abrupt thawing are still likely to occur.
For many years, scientists have feared that rising temperatures will trigger the release of carbon stored in frozen soil of the Arctic, which in turn, will accelerate climate change.
Permafrost is the soil that has remained frozen for years or centuries under topsoil.
"Over a few decades, thermokarst lake growth releases substantially more carbon than lake loss can lock in permafrost again [when the lake bottoms refreeze]", explains co-author Guido Grosse, from the Alfred Wegener Institute. This byproduct then enters into the atmosphere and contributes to climate warming, researchers say.
Bubbles of methane in a lake where permafrost is melting below and releasing greenhouse gases into the atmosphere. Also, they measured carbon release from different locations across Siberia and Alaska on those lakes, and five more locations away from the lakes to find how much of the greenhouse gas was made, and the age of the carbon that was hidden below the permafrost. Within my lifetime, my children's lifetime, it should be ramping up ... "It's already happening but it's not happening at a really fast rate right now, but within a few decades, it should peak", she explained.
Walter Anthony said she's been measuring methane releases since 2001, but most of the calculations incorporated into the study have been within the past 2 1/2 years.
