Melting glaciers in the Arctic release methane

As Svalbard’s glaciers move and leave land behind, underground water seeps upward and forms springs. The scientists found that in 122 out of 123 of them, the water is filled with apparently ancient methane in very high concentrations that flow upwards under pressure. The amount of emissions that these springs emit is not well defined.

“This is a feedback loop caused by climate change,” said Gabrielle Kleiber, lead author of the study and a scientist at the University of Cambridge and University Center in Svalbard. “Glaciers are retreating due to a warming climate, and these exposed fore fields are left behind, which encourages the release of methane.”

Of most concern is the apparent age of the methane – the fact that it looks so old indicates that it could have come from very large underground reservoirs with the potential to release a lot of the gas. The researchers found that the most intense outflows of gas occurred in regions with
Underground rock layers that are millions of years old.

“It’s not the methane gas that microbes produce contemporaneously,” Kleber said, “it’s the methane that was created when rocks formed.”

This indicates that the gas has been sequestered for long periods in ancient deposits of fossil fuels, particularly natural gas and coal – but that something removed recently is what scientists call “ice capIt kept a lid on the methane, and removing it allowed the settled gas to escape upwards. Svalbard is widely known for being rich in fossil fuels – and the largest settlement, Longyearbyen, was originally established as a coal-mining town.

Scientists said the current phenomenon could certainly be happening in many places other than Svalbard, which could add another accelerator to warming in the Arctic.

“Shale is the most abundant rock on Earth, and there is a lot of it in the Arctic (or rocks like it),” said Andy Hudson, study co-author and scientist at the University of Norway Center in Svalbard.

the study It was published Thursday in Nature Geoscience by Kleber, Hodson, and colleagues at universities in Norway, Canada and the United Kingdom. The scientists studied 78 glaciers on Svalbard that depend on land in the course of their research and several additional glaciers that extend all the way to the ocean.

If methane emissions represent a new phenomenon associated with global warming, Svalbard is the place to be. The island chain experienced an unusually high temperature, which caused a strong retreat of glaciers. Svalbard has improved greatly since 1976, based on Temperature measurements were taken at Svalbard Airport near Longyearbyen.

There is no official estimate of the large amount of methane emissions caused by retreating glaciers around the world. This phenomenon will add an additional source of methane emissions in the Arctic. Scientists have found that thawing permafrost Also called Gas in the atmosphere, but the phenomenon is not well understood. that Formal scientific assessment That puts those between zero and one million tons of methane annually, underlining the uncertainty about the scale of the problem.

Emissions from retreating glaciers are a different source, Kleiber said — there is usually no permafrost under glaciers. Instead, the glacier ice itself, crushing the Earth down, acts as the apparent cap trapping the methane within.

Kleiber and his colleagues estimate that 231 tons of methane could be emitted in Svalbard each year because of the process they discovered. By comparison, Norway mentioned 105,940 tons of methane emissions from its agricultural sector, which is the largest source of emissions of this gas, in 2021 (the latest reporting year).

Overall, emissions associated with the retreat of glaciers on Svalbard will account for just over 1 percent of Norway’s total methane emissions for 2021. Among countries, Norway itself is a relatively small emitter of methane.

The real fear isn’t what’s happening on Svalbard, but rather, what it would mean if the phenomenon were more widespread – or if it was about to be exacerbated by more glacier retreat. Kleiber notes, for example, that glaciers that are currently seeping into the ocean are also retreating, in many cases retreating to land and thus again exposing land surfaces that could have methane beneath.

“As more land is exposed, we have more springs that are going to come out,” Kleber said.

said Katie Walter Anthony, a researcher at the University of Alaska, Fairbanks, who studies these emissions across the lower and sub-frozen north.

In one instance, Walter Anthony A bubbling lake Alaska was also emitting ancient geological methane at an alarming rate of about 11 tons of the gas per day.

The latest study “is important because it shows just how ubiquitous it is [methane] “It seeps from various origins in the glacier retreat environment,” Walter Anthony said in an email. “Similar methane-rich seeps have been found in Alaska and Greenland along the edges of glaciers and ice sheets.”

in 2012 studyWalter Anthony and a team of scientists have estimated that 2 million tons per year of ancient methane, stored deep underground, could seep into the air across the Arctic as permafrost thaws, new lakes form and other changes provide new pathways for it to reach the atmosphere. Based on the new study, Anthony now says that number could be “much larger.”

Jesper Riess Christiansen, a scientist at the University of Copenhagen added and conducted Lesson Methane emissions are associated with glaciers in Greenland. “It’s only been the past seven years that people have actually studied this.”

However, Christiansen said the authors can do more to prove that the methane they find is very old, as the paper notes.

The age of the gas is important because scientists believe that methane underground is associated with fossil fuel deposits — but this is different from emissions of methane near the surface that microorganisms produce all the time.

“There are still some missing pieces of this puzzle,” Christiansen said.

And the search continues, against the backdrop of the picturesque but also wild Svalbard, which is famous for its large number of polar bears. Speaking from Rindersbukta, a fjord in Svalbard where a chain of glaciers ends, Temperatures were close to 60 degrees Fahrenheit that day, Kleiber noted, “extremely hot in a Svalbard summer. The rivers are raging.”

“It’s kind of a dismal concept to watch hundreds of cubic meters of water flash before our eyes and know in our current climate, that ice will never be replaced,” Kleiber continued. “And then we have these methane springs falling before the glacier.”