Arctic Tundra Shifts From Carbon Sink to Source as Permafrost Thaws

A new study reveals over a third of the Arctic-boreal region now emits more carbon than it absorbs, driven by warming temperatures and wildfires.

The Arctic-boreal region, historically a major carbon sink, is now a net emitter of carbon dioxide across 34% of its area, rising to 40% when wildfire emissions are included.
Thawing permafrost, which contains vast amounts of stored carbon, is a key driver of this shift, as warming temperatures accelerate decomposition and greenhouse gas release.
The study, published in *Nature Climate Change*, combines three decades of satellite and field data from over 200 sites, offering the most comprehensive assessment of the region's carbon flux to date.
While some areas are experiencing increased vegetation growth due to longer growing seasons, this 'greening' is insufficient to offset emissions from thawing soils and wildfires.
Researchers warn that these changes in the Arctic carbon cycle could significantly impact global climate targets, as permafrost emissions are not always accounted for in national carbon budgets.