London, Nov 27: Global warming will progress faster than previously believed because greenhouse gas emissions that arise naturally are also affected by increased temperatures, researchers, including one of Indian-origin, have warned.
Researchers examined the emissions of the greenhouse gas methane from three lakes. The effects were clear and the methane emissions increased exponentially with temperature.
Their measurements show that a temperature increase from 15 to 20 degrees Celsius almost doubled the methane level.
"Everything indicates that global warming caused by humans leads to increased natural greenhouse gas emissions. Our detailed measurements reveal a clear pattern of greater methane emissions from lakes at higher temperatures," said Sivakiruthika Natchimuthu, doctoral student at Linkoping University in Sweden and lead author of the study.
Greenhouse gas emissions from the burning of fossil fuels lead to higher temperatures, which in turn lead to increased natural emissions and further warming.
"We are not talking about hypotheses anymore. The evidence is growing and the results of the detailed studies are surprisingly clear," said David Bastviken, professor at Tema Environmental Change, Linkoping University.
"The question is no longer if the natural emissions will increase but rather how much they will increase with warming," said Bastviken.
This means that warming will be faster than expected from anthropogenic greenhouse gas emissions alone, researchers said.
Any reductions in anthropogenic greenhouse emissions is a double victory, by both reducing the direct effect on warming, but also by preventing the feedback with increased natural emissions, they said.
The study was published in the journal Limnology and Oceanography.