A methane feedback loop that is beyond humans’ ability to control may have begun, scientists with the National Oceanic and Atmospheric Administration (NOAA) have said.
Methane is a powerful greenhouse gas emitted into the atmosphere from both human activities and natural processes. It is the second biggest contributor to climate change after carbon dioxide.
According to the NOAA, methane is 25 times more powerful at trapping heat in the atmosphere compared to carbon dioxide. While it remains in the atmosphere for a much shorter time than carbon dioxide, it has a huge impact on the rate of climate change.
Research published by the NOAA now shows that 2021 saw the largest annual increase in atmospheric methane levels since measurements began in 1983.
Xin Lan, a research scientist at the NOAA, told Newsweek that after 2006, the majority of methane emissions produced were caused by natural wetlands and man-made emissions. Natural wetlands produce methane when organic matter decays , while and man-made emissions are caused by livestock, waste and landfills.
It is difficult for scientists to determine which emissions come from which source. However, natural methane production is accelerated by rain and varying temperatures, which climate change is already causing.
Lan said that because the Earth’s climate is already warming the methane produced from natural wetlands is only set to increase. This signals the beginning of a feedback loop—an ongoing cycle that cannot be broken.
“From natural processes, we know that wetland methane emissions are sensitive to change in precipitation and temperature,” she said. “Methane production from microbes increases with increases in global temperature which is driven by long-term greenhouse gas emissions. More atmospheric methane, in turn, can further warm up the earth. That’s the feedback loop we are referring to.”