SOURCE: University of London, Nature Climate Change

DATE: June 29, 2020

SNIP: New research suggests that as the Earth warms natural ecosystems will release more of the greenhouse gas methane than expected from predictions based on temperature increases alone.

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.”

Dr Kevin Purdy, Associate Professor of Microbial Ecology at Warwick, added: “Our studies have led to a better understanding of how global warming can affect methane emissions from freshwaters. This means that future predictions of methane emissions need to take into account how ecosystems and their resident microbial communities will change as the planet warms.”