A third of the Arctic’s tundra, forests and wetlands have become a source of carbon emissions, a new study has found, as global heating ends thousands of years of carbon storage in parts of the frozen north.
For millennia, Arctic land ecosystems have acted as a deep-freeze for the planet’s carbon, holding vast amounts of potential emissions in the permafrost. But ecosystems in the region are increasingly becoming a contributor to global heating as they release more CO2 into the atmosphere with rising temperatures, a new study published in Nature Climate Change concluded.
More than 30% of the region was a net source of CO2, according to the analysis, rising to 40% when emissions from wildfires were included. By using monitoring data from 200 study sites between 1990 and 2020, the research demonstrates how the Arctic’s boreal forests, wetlands and tundra are being transformed by rapid warming.
“It is the first time that we’re seeing this shift at such a large scale, cumulatively across all of the tundra. That’s a pretty big deal,” said Sue Natali, a co-author and lead researcher on the study at the Woodwell Climate Research Center.
The study comes amid growing concern from scientists about the natural processes that regulate the Earth’s climate, which are themselves being affected by rising temperatures. Together, the planet’s oceans, forests, soils and other natural carbon sinks absorb about half of all human emissions, but there are signs that these sinks are under strain.