Chinese scientists recently found that if the global temperature increases by 1.5 to 2 degrees Celsius, the role of wetlands as sinks for greenhouse gases will be reduced by more than half.
Wetlands have high potential to mitigate climate change due to their large carbon stocks. However, it is not known with certainty if and where wetlands due to warming would act as a sink for greenhouse gases or as a source of them.
Researchers from the Institute of Atmospheric Physics of the Chinese Academy of Sciences integrated data from warming simulations conducted at 167 independent natural wetlands between 1990 and 2022. They studied the response of the net exchange of three greenhouse gases to warming.
The study, published in the journal Nature Climate Change, shows that if global temperatures rise by between 1.5 and 2 degrees Celsius, the role of wetlands as sinks for greenhouse gases will weaken by about 57 percent, and their role in climate change mitigation will be considerably weakened.
In wetlands dominated by vascular plants such as shrubs and grasses, warming increased the carbon dioxide sink effect. However, in wetlands dominated by mosses, lichens, and other cryptogamous plants, warming increased carbon dioxide emission.
Warming also increased the net emission of methane and nitrous oxide from wetlands regardless of their dominant plants, according to the study.
“The Paris Agreement aims to keep global warming below 2 degrees Celsius above pre-industrial levels and strive for a lower limit of 1.5 degrees Celsius. In this context, our study on changing wetlands as greenhouse gas sinks will help to better cope with global climate change,” said Xu Xiyan, one of the researchers.