Permafrost, the frozen ground that underlies much of the Arctic and can be hundreds of feet deep, contains the remains of plants and animals accumulated over centuries. As rapid warming in the region has caused more of the topmost frozen layer to thaw, organic matter has been decomposing and emitting carbon dioxide and methane.
Permafrost is thought to contain about twice as much carbon as is now in the atmosphere. But as the Intergovernmental Panel on Climate Change noted last year as part of its Sixth Assessment Report, the size and timing of emissions from thawing permafrost are uncertain.
“That uncertainty has been a major barrier to the incorporation of permafrost emissions into global climate policy,” Dr. Natali said.
John Holdren, the White House science adviser in the Obama administration and a director of the Arctic Initiative at the Belfer Center, said that better measurements, used to develop improved models, “could help us not only put together a more complete picture of what is happening now, but would give us a better capacity to project what is likely to happen in the future.”
Permafrost thaw does not only have global effects. Locally throughout the Arctic it has caused roads, bridges, homes and other structures built in frozen ground to become unstable and unusable. Melting permafrost has also resulted in greater erosion, leading to land collapse and flooding.