A new study reveals that peatlands in the Arctic are growing due to rapid regional warming and increased precipitation, potentially storing more carbon but also heightening the risk of releases through fires. Researchers warn of a dangerous feedback loop as these carbon-rich ecosystems respond to climate changes. The findings highlight the dual role of these landscapes in global warming mitigation.
Peatlands cover just 3 percent of Earth's surface but store 600 billion metric tons of carbon, surpassing the total in all forests worldwide. These waterlogged soils, rich in undecayed plant matter, act as vital carbon sinks. A recent study, published earlier this month, shows Arctic peatlands expanding amid the region's accelerated warming—four times faster than the global average—combined with rising precipitation that fosters plant growth and slows decomposition.
The research, led by paleoecologist Josie Handley of the University of Cambridge, attributes this to Arctic greening: diminishing ice exposes darker land and water, absorbing more sunlight and driving further warming. This promotes shrub expansion and moisture from reduced sea ice evaporation. "Things are getting greener, but they're also getting wetter," Handley said. "That's all really good conditions for the formation of peat."
Field sampling in the Arctic confirmed peat accumulation, particularly from sphagnum moss, which retains water even after death, sustaining further growth. The study dates material via carbon and lead content, indicating peatlands now span more area than at any point in the last three centuries. Thawing permafrost and receding glaciers open new land for colonization, while lengthening growing seasons aid moss buildup.
However, biogeochemist Angela Gallego-Sala of the University of Exeter, a coauthor, cautions: "What is clear is that the more extreme climatic changes that we have, the more likely it is that they will release more carbon into the atmosphere." Extreme dry periods fuel wildfires, including persistent "zombie fires" that smolder underground through winter. Ecohydrologist Mike Waddington of McMaster University, not involved, noted local hydrology's role in initiating shallow peat formation that could deepen.
This expansion creates a self-sustaining cycle but risks a carbon "burp" if drying leads to fires, balancing sequestration against potential emissions as the Arctic transforms.