Alaska Shows no Sign of Rising Methane Levels, For Now
Climate scientists will be happy to hear that Alaska, despite large temperature increases in recent decades, is showing no signs of rising methane levels, at least for now.
Previous studies had suggested that methane from Alaskan soils was being released at unusually high rates, but the new NASA-led study, suggests otherwise, and "That's good news, because it means there isn't a large amount of methane coming out of the ground yet," lead author Rachel Chang said in a news release.
However, that doesn't mean that that can't change in the future.
Methane is the third most common greenhouse gas in the atmosphere, after water vapor and carbon dioxide, and the most potent. It is 33 times more effective than carbon dioxide at trapping heat in the atmosphere and adding to greenhouse warming.
Scientists have shown that vast amounts of carbon dioxide in the form of methane are stored in undecayed organic matter - dead plants and animals - in Arctic permafrost. Permafrost absorbs so much carbon that the frozen North contains about twice as much as there is in the atmosphere today. And while that's good news, keeping the greenhouse gas from building up in the air, this system could one day be compromised.
As the world continues to warm, Arctic permafrost is thawing out and threatens to release all of this stored methane and greatly impact global temperatures. And even though Alaska composes just about one percent of Earth's total land area, it still contains enough carbon to make a dent in greenhouse gas levels.
High concentrations of atmospheric methane have been measured at individual Arctic sites, especially in Siberia, but NASA's multiyear Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) was the first to establish emission rates for such a large region of the Arctic.
In the new study, published in the journal Proceedings of the National Academy of Sciences, researchers analyzed methane measurements made over Alaska from May through September 2012. Researchers cannot say for sure whether emissions have already increased or stayed the same, leaving scientists wondering how much of the soil's stored carbon will eventually gets released into the atmosphere as methane as permafrost continues to thaw more and more.