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IMAGE: Researchers from the US and Canada found evidence in mineral deposits from caves in Canada that permafrost thawing took place as recently as 400,000 years ago, in temperatures not much. view more
Credit: Jeremy Shakun, Boston College
Chestnut Hill, Mass. (4/28/2021) The vast frozen terrain of Arctic permafrost thawed several times in North America within the past 1 million years when the world s climate was not much warmer than today, researchers from the United States and Canada report in today s edition of
Science Advances.
Arctic permafrost contains twice as much carbon as the atmosphere. But the researchers found that the thawings which expel stores of carbon dioxide sequestered deep in frozen vegetation were not accompanied by increased levels of CO2 in the atmosphere. The surprising finding runs counter to predictions that as the planet warms, the volume of these natural carbon stores can add significantly to CO2 produced by human activity
Massachusetts Institute of Technology
Nearly one quarter of the land in the Northern Hemisphere, amounting to some 9 million square miles, is layered with permafrost – soil, sediment, and rocks that are frozen solid for years at a time. Vast stretches of permafrost can be found in Alaska, Siberia, and the Canadian Arctic, where persistently freezing temperatures have kept carbon, in the form of decayed bits of plants and animals, locked in the ground.
Scientists estimate that more than 1,400 gigatons of carbon is trapped in the Earth’s permafrost. As global temperatures climb, and permafrost thaws, this frozen reservoir could potentially escape into the atmosphere as carbon dioxide and methane, significantly amplifying climate change. However, little is known about permafrost’s stability, today or in the past.
Credits: Courtesy of the researchers Terms of Use: Images for download on the MIT News office website are made available to non-commercial entities, press and the general public under a Creative Commons Attribution Non-Commercial No Derivatives license. You may not alter the images provided, other than to crop them to size. A credit line must be used when reproducing images; if one is not provided below, credit the images to MIT. Caption: Earth’s permafrost shifted to a more stable state in the last 400,000 years and has been less susceptible to thawing since then, according to a new study by MIT researchers and their colleagues, who are pictured here on a research expedition.
Cave deposits show surprising shift in permafrost over the last 400,000 years eurekalert.org - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from eurekalert.org Daily Mail and Mail on Sunday newspapers.