Madrid. Parts of the Arctic have deeper-than-normal snow cover that drives the thawing of carbon stores in long-frozen permafrost.
This phenomenon is causing an increase in the emissions of greenhouse gases such as carbon dioxide and methane, according to new research led by Earth system scientists at the University of California at Irvine.
“This is the first long-term experiment where we directly measure the mobilization of ancient carbon throughout the year to show that deeper snow has the potential to mobilize carbon quite rapidly deep in the ground,” Claudia explained in a statement. Czimczik, a professor of Earth system sciences and lead author of the study, who appears in AGU Advances.
“It supports the idea that carbon emissions from permafrost will contribute to atmospheric carbon dioxide levels, which are already rising.”
Fieldwork for the study was conducted at the International Tundra Experiment (ITEX) at Toolik Lake in Alaska, a trial initiated in 1994 by study co-author Jeff Welker of the University of that town. The original goal, he noted, was to understand how deeper snow would affect arctic tundra ecosystems.
In recent years, the team conducted fieldwork at the ITEX site and found that a common arctic ecosystem, scrub tundra, had become a year-round source of ancient carbon dioxide. This was the result of thawing of permafrost buried under snow where the snow has been three to four times deeper than the long-term average depth since 1994.
When the research began, neither Welker’s team nor the climate scientists thought that the experimental treatment of deeper snow would lead to such rapid thawing of the permafrost.
“These findings suggest that permafrost stability in Arctic Alaska, and possibly globally, may respond fairly rapidly to changes in Arctic winter snow conditions, where that time of year can last up to eight months. ”, he added. “Winter weather feedbacks like this are a previously unrecognized and unrecognized feature of the tundra.”
The team’s findings, Czimczik noted, suggest that even if humanity stopped emitting planet-warming gases like carbon dioxide immediately, those from Arctic sources would continue.
“If the climate models are correct and observations continue to show an increase in snowfall, in addition to strong warming, the latter will greatly accelerate emissions from permafrost,” Czimczik said. “I was very concerned when I saw the data.”
So far, the climate change models that help groups like the Intergovernmental Panel on Climate Change forecast different climate change scenarios do not take emissions from permafrost into account in part because they are hard to quantify. But Czimczik and his team built sensors at the University of California, Irvine, and were able to measure them directly at their field site in the Arctic.
“We weren’t sure we could see them. However, it is even possible to look at ancient carbon emissions during the summer,” when those from plants should be dominant, he said.
Student Shawn Pedron and University of Alaska postdoctoral researcher Gus Jespersen installed the sensors in 2019.
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