All over the Arctic there are lakes where the water seems to be boiling. Where “drunk” forests plunge into the water. Where huge sinkholes appear after mammoth explosions – a witness to one such event said it was “like the earth is breathing”.
The cause of these natural phenomena is methane, a powerful greenhouse gas with a global warming potential that is around 30 times higher than carbon dioxide in 100 years. Methane is formed through a number of natural and anthropogenic processes. Agriculture is a major contributor, as are landfills and coal mines. In natural springs, it comes from both land and sea.
One particular source of methane – permafrost – is becoming less and less stable. Permafrost is ground that has been frozen permanently, in some cases for hundreds of thousands of years. Organic matter is trapped in this frozen ground. As the soil thaws, the organic matter thaws and begins to decompose, releasing methane.
Katey Walter Anthony has spent her career understanding methane emissions and studying Arctic lakes formed by thawing permafrost. In her new book, she has written about her life and work, from the Siberian tundra to the Alaskan wilderness Chasing Lakes: Love, Science and the Mysteries of the Arctic. She was also featured in the PBS NOVA film Arctic sinkholeswhich aired in February.
“You look like the water is boiling,” she said news week. “For example, there’s this violent bubbling boil, sometimes there’s a noise and so it can be almost scary.”
Walter Anthony discovered that lakes emitted methane while working as a graduate student in Siberia. She had set methane traps to understand how much was coming out of the Siberian lakes. “I could see the methane coming out, but they didn’t go into my traps,” she said. “One year I’m at my wit’s end to spend the winter in Siberia – many scientists return to their universities in the fall.
“Everything froze. I went out on the ice with my monitors and what we saw blew my mind. We saw ice bubbles in the pitch black lake. There were these white beautiful clusters of bubbles. They weren’t everywhere… They were point sources and they were very strong… It was like looking up at the sky at night and most of the sky is black. Well, on a clear night you can see stars, and so there was methane in the lake. There were thousands of dots bubbling up.
Walter Anthony had realized that to get a measure of how much methane was escaping from the lakes, she needed to find the point source. “It was a eureka moment,” she said.
She and her husband are now tracking methane lakes in the Arctic. Because of the country’s vastness and remoteness, it’s unclear how many of these permafrost lakes are out there. It’s not even clear if new lakes are forming or are just now being discovered by scientists. But understanding methane emissions — from all sources around the world — is hugely important to understanding what role they might play in future climate change.
The idea of a methane feedback loop has been around for decades. As the Earth warms, permafrost thaws and releases more methane. The more methane released, the more the earth warms, causing more permafrost to thaw and more methane to be released. Etc.
Walter Anthony is clear. Methane does not play a major role in efforts to keep global warming below 1.5 degrees Celsius at pre-industrial levels. Although carbon dioxide is less potent than methane, far more is released into the atmosphere. It also has a longer lifespan. While methane stays in the atmosphere for about a decade, carbon dioxide can stay there for between 300 and 1,000 years.
“We’re not going to have a time bomb,” she said of the permafrost thawing. “It’s not catastrophic, but it’s an important headwind.” The problem is that unless global warming is curbed, “opening the freezer door will be enough.”
“And a freezer only holds so much food. So does the permafrost. There’s a finite amount of frozen carbon in permafrost, and when you open it up and break it down, it produces greenhouse gases.
“There’s no way to refreeze the permafrost… and that’s, well, worrying.”
Walter Anthony is now working on mapping permafrost dew lakes in the Arctic and is developing remote sensing methods for this purpose. Their latest technology involves a synthetic radar that can see through snow and clouds, providing a bright signal where bubbles and gas are present. Once discovered, these lakes must then be confirmed through field work.
Through these travels, she says she sees firsthand how the world is changing.
“As the permafrost gets warmer, it thaws. Methane comes out and I see that in lakes, but it’s only in the last five years that I’m like, ‘Wow, the ground around me is changing so fast.’ It wasn’t like that a few years ago,” she says. “The places where there was permafrost [thawing] On the edges of lakes, now my way to the lake is humiliating. Where there used to be land, huge canyons form lakes.
“It feels like things are going faster. Of course we need a long record and we need all these paleo records to put it in context. But I see dramatic changes that feel like acceleration.”
Walter Anthony said some models suggest there could be an abrupt change in methane emissions this century. Data from NOAA shows that in 2021, atmospheric methane levels were at their highest levels on record for the second year in a row, although the reason is not entirely clear.
Studies suggest that when Earth moved from the Ice Age to the current interglacial period in which we live, methane emissions were about 10 times higher than they are today. Walter Anthony’s research on lakes shows that emissions are increasing, which could mean we’ve already started down this path.
In the coming decades, she said, we’ll see if the models are right.
“We’re on the threshold,” she said.
https://www.newsweek.com/methane-arctic-sinkholes-lakes-emissions-climate-change-1710842 The arctic lakes, where methane roars the waters in a violent, rolling boil