Arctic climate researchers are at this point warning us that 2023 may be the tipping point in the methane climate feedback loop, with up to a million of tons of methane trapped under glaciers now free to enter the atmosphere and rapidly making things warmer and warmer in the years ahead.
Scientists working in one of the world’s fastest-warming places found that rapidly retreating glaciers are triggering the release into the atmosphere of methane, a potent greenhouse gas that causes global temperatures to rise.
The releases are triggered as glaciers across the archipelago of Svalbard, Norway, rapidly retreat and leave behind newly exposed land, scientists said. If the phenomenon is found to be more widespread across the Arctic — where temperatures are quickly rising and glaciers melting — the emissions could have global implications.
As the Svalbard glaciers move and land is left behind, groundwater beneath the Earth seeps upward and forms springs. In 122 out of 123 of them, the scientists found, the water is filled with apparently ancient methane gas at very high concentrations that bubble upward under pressure. The amount of emissions these springs are emitting are not well-quantified.
“This is a feedback loop that’s caused by climate change,” said Gabrielle Kleber, the study’s lead author and a scientist based at the University of Cambridge and the University Center in Svalbard. “Glaciers are retreating due to climate warming, and they are leaving these exposed forefields behind, which are encouraging methane gas to be released.”
Most concerning is the apparent age of the methane — the fact that it appears to be ancient suggests it could be coming from very large underground reservoirs with the potential to unleash a lot of gas. The researchers found that the most intense gas flows occurred in regions with underground shale layers that are millions of years old.
“It’s not methane being produced contemporarily by microbes, it’s methane that was created when the rocks were formed,” said Kleber.
This implies that the gas has been sequestered for long periods in ancient deposits of fossil fuels, principally natural gas and coal — but that something has recently removed what scientists call a “cryospheric cap,” once provided by glaciers or permafrost. It kept a lid on the methane, and its removal allowed the once stable gas to escape upward. Svalbard is widely known to be rich in fossil fuels — 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, potentially adding another accelerator of warming in the Arctic.
“Shale is Earth’s most abundant sedimentary rock, and there’s plenty of it in the Arctic (or rocks like it),” Andy Hodson, a co-author of the study and also a scientist at Norway’s University Centre in Svalbard, said in an email.
The study was published on Thursday in Nature Geoscience by Kleber, Hodson and colleagues based at universities in Norway, Canada and the United Kingdom. The scientists studied 78 Svalbard glaciers that are based on land and several additional glaciers that stretch all the way into the ocean.
If the methane releases represent a new phenomenon tied to the warming of the planet, Svalbard is an appropriate place for it. The string of islands has seen extraordinary warming, causing the strong retreat of glaciers. Svalbard has warmed dramatically since 1976, based on temperature measurements taken at the Svalbard airport near Longyearbyen.
There’s no official quantification of how large methane emissions from retreating glaciers around the world could be. The phenomenon would add an additional source of methane emissions in the Arctic. Scientists have found that thawing permafrost also releases the gas into the atmosphere, but the phenomenon is not well understood. An official scientific assessment puts those at between zero and 1 million tons of methane per year, underscoring the uncertainty about the scope of the problem.
The emissions from retreating glaciers would count as a different source — there is usually no permafrost beneath the glaciers, Kleber said. Rather, the glacier ice itself, which crushes the ground downward, is serving as the apparent cap holding the methane in.
And there's no putting the cap back on this genie's bottle. We're on the roller coaster to hell, and we're all going to roast soon.
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