Warming experiments turn Minnesota peat bogs from carbon sinks into emitters in three years

In a large-scale field study, Oak Ridge National Laboratory researchers warmed peatland enclosures in Minnesota's Marcell Experimental Forest by up to 9 °C, some with added carbon dioxide. Within three years, all heated plots reversed from carbon sinks to sources, releasing carbon dioxide and methane at rates up to twenty times faster than past accumulation. The transition occurred even at the lowest temperature increase of roughly 4 °F, showing a strong linear link between heat and carbon loss.

Declining sphagnum moss, a key carbon-storing species, contributed significantly to the net emissions. The findings, published in AGU Advances, suggest that rising temperatures could rapidly turn peatlands into major greenhouse-gas sources worldwide.