Scientists estimate that 20 to 90 percent of the organic carbon pool in permafrost can be decomposed by microbes, converting it to greenhouse gases that warm the atmosphere. The warmer atmosphere causes additional thawing, creating a cycle that gets warmer and warmer.
For the study, the research team built snow fences to create snowdrifts in the winter to warm the soil of the Alaskan tundra beneath.
"This will be interesting for Floridians, but if you catch a whole bunch of snow in a giant pile, that actually keeps the tundra warmer than it would be," Schuur said. "It's like a giant blanket that insulates the tundra soils from the cold air."
The extra snow, however, would cause an artificially late spring, and the research team needed to measure typical spring warming.
"So we go up to Alaska and shovel all these drifts of snow away in April," Schuur said. "Alaskans think it's crazy."
One of the successes of the experiment, Schuur said, was finding a way to model carbon release from permafrost in the environment on a year-round basis. Previous studies had used miniature greenhouses in summer months, but creating a warming situation in the winter was more challenging.
"We wanted to warm the tundra and cause the permafrost to recede. This is the first experiment to isolate that effect in the field, so the first thing we show is that we're able to simulate what will happen in a future world when the permafrost degrades," Schuur said.
Laboratory experiments, too, remain vitally important, Schuur said. A recent study in Nature Climate Change in which Schuur participated, examined 12 years of permafrost samples, an unusually long time frame for such studies. The research showe
|Contact: Ted Schuur|
University of Florida