Despite significant temperature increases in Alaska, a new analysis of NASA airborne data found the local soil is not releasing higher-than-normal levels of methane into the atmosphere, despite recent modeling studies that have suggested otherwise.
Concentrations of methane have been detected at high rates at individual Arctic sites, contributing to the idea that it is being rapidly released from the soil, NASA's Jet Propulsion Laboratory (JPL) reported. A recent experiment is the first to establish emission rates for this region of the Arctic.
Methane is the third most common greenhouse gas found in the atmosphere behind water vapor and carbon dioxide, but it is 33 times more effective at trapping heat in the Earth's atmosphere. Alaska takes up about one percent of the world's total land area, and it also made up about one percent of the total methane emissions in 2012. This means the Alaskan rate was very close to the global rate during that time.
"That's good news, because it means there isn't a large amount of methane coming out of the ground yet," said lead author Rachel Chang, formerly at Harvard University, Cambridge, Massachusetts, and now an assistant professor and Canada Research Chair in Atmospheric Science at Dalhousie University, Halifax, Nova Scotia.
Large amounts of carbon is stored in the frozen organic matter of Alaska, but this greenhouse gas will not be released unless the land is thawed. If this matter was defrosted, researcher predict it would have an enormous impact on the global climate.
To make their findings researchers with the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) have made frequent flights across Alaska using the Sherpa C-23B aircraft, which analyzes methane and carbon dioxide emissions.
"One of the challenges is that we have nothing to compare our results to. We can't say whether emissions have already increased or stayed the same. Our measurements will serve as a baseline," Chang said.
The findings were published in a recent edition of the Proceedings of the National Academy of Sciences.
