At Chandalar Shelf in Alaska, a site about 200 kilometres (124 miles) north of the Arctic Circle, I kneeled on the damp, muddy ground, and plunged in a small serrated shovel. It easily penetrated the loamy top layer before I heard it thunk and scrape against the cold, frozen ground beneath—permafrost.
This permanently frozen ground, together with the layers of soil above it, stores vast amounts of carbon from organic material that's accumulated over millennia. Organic material decomposes slowly in the Arctic's cold, wet conditions. If it thaws, microbes in the soil break it down, emitting methane and carbon dioxide, and quickly releasing carbon that was stashed there over thousands of years.
"The permafrost is definitely getting warmer," said Alexander Kholodov from the University of Alaska Fairbanks, as he looked at the temperature readout from a probe buried in the ground. He was one of the lead researchers who I accompanied on this expedition.
While Kholodov recorded properties of the soil, I took soil samples and measured the depth of the permafrost. Nearby, Mike Loranty from Colgate University sat hunched over a small plot of earth. He was clipping off shrubs and grasses, sorting them into paper bags to identify what kinds of vegetation were growing and to estimate their relative abundance. We were compiling an inventory of all the components in the ecosystem to understand how the plants and the soil affect the thermal properties of the underlying permafrost.
Thawing permafrost is already wreaking havoc with Alaskan roads and buildings, but the potential for massive amounts of carbon to be released and contribute to a warming climate is a global concern.
The Alaskan landscape isn't uniform, so the way it's thawing isn't either. Since vegetation influences the temperature and rate of thaw, Loranty, Kholodov, and the rest of their team are trying to sort out how the variety of trees, shrubs, grasses, lichens, and mosses impact permafrost temperature in ecosystems across Alaska. It's part of a five-year project that spans from Alaska to Siberia and the data will help to predict how climate change will differentially influence the Arctic.
I always wondered how scientists study permafrost in an area as large and diverse as the north, so I joined this team of researchers for three weeks. We travelled over 800 kilometres (roughly 500 miles) from Fairbanks, up the Dalton Highway through mountain passes, to the open tundra at the end of the road at Prudhoe Bay on the Arctic Ocean.
Read the full article on Motherboard.