The study, published today in Nature Climate Change, attributes this difference to changes in the balance of microbial communities within ecosystems that regulate methane emissions.
The production and removal of methane from ecosystems is regulated by two types of microorganisms, methanogens - which naturally produce methane - and methanotrophs that remove methane by converting it into carbon dioxide. Previous research has suggested that these two natural processes show different sensitivities to temperature and could therefore be affected differently by global warming.
Research led by Queen Mary University of London and the University of Warwick studied the impact of global warming on freshwater microbial communities and methane emissions by observing the effect of experimental warming of artificial ponds over 11 years. They found that warming produced a disproportionate increase in methane production over methane removal, resulting in increased methane emissions that exceeded temperature-based predictions.
Professor Mark Trimmer, Professor of Biogeochemistry at Queen Mary, said: “Our observations show that the increase in methane emissions we see is beyond what you could predict based on a simple physiological response to the temperature increase. Long-term warming also changes the balance in the methane-related microbial community within freshwater ecosystems so they produce more methane while proportionately less is oxidised to carbon dioxide. As methane is a far more potent greenhouse gas than carbon dioxide, together these effects increase the global warming potential of the carbon gases released from these ecosystems.”
Read more at Queen Mary University of London
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