Global Warming Creates More Global Warming: New Study Links Temperature To Methane Production
One consequence of a warming planet will be more emissions of the powerful greenhouse gas methane during decomposition. Now, British scientists who say they've calculated the rate that temperature speeds up methane release, which will help with climate change predictions.
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"This is important because biological methane fluxes are a major component of global methane emissions, but there is uncertainty about their magnitude and the factors that regulate them," said lead researcher Gabriel Yvon-Durocher, of the University of Exeter, in a statement. The paper was released Wednesday in the journal Nature. "This hinders our ability to predict the response of this key component of the carbon cycle to global warming."
What's perhaps most surprising about the topic of research is the direct source of the "pollution." Far from smokestacks or the agriculture sector, natural aquatic landscapes, like lakes and marshes, contribute a sizable portion of the heat-trapping greenhouse gases emitted into the atmosphere. According to the Environmental Protection Agency, nearly 40 percent of global methane emissions come from natural, not manmade, sources.
Much of that portion is derived from the decomposition of organic matter by ancient, anaerobic microbes called Archaea. They eat dead plants and animals and release methane as a byproduct; the process is called methanogenesis. Yvon-Durocher says methane in the atmosphere has caused about one-fifth of all global warming since before industrialization, in part because methane is 25 times stronger than carbon as a greenhouse gas.
"Like most other forms of metabolism, methanogenesis is temperature-dependent," the authors wrote. That is, higher temperatures speed up the process. But until recently, no one had attempted to discover the relationship between global temperatures and the amount of methane drifting into the sky. In 2010, Yvon-Durocher led a study describing for the first time a "positive feedback loop" in freshwater ecosystems — global warming was speeding up one of the causes of global warming. Calculating how higher temperature correspond to methane output would help climatologists predict future warming trends.
The new study looked at methane emissions from a range of aquatic ecosystems and found that methanogenesis increases 57-fold between 32 degrees Fahrenheit and 86 degrees Fahrenheit as the temperature fluctuated between seasons. "Our research provides scientists with an important clue about the mechanisms that may control the response of methane emissions from ecosystems to global warming," they wrote in the paper.
"More research, using our results as a platform for refining Earth system models, is required to explore the consequences of our findings for future levels of climate change," Yvon-Durocher says.
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