Fires, intensified by climate change, release carbon trapped in soil and plants. More frequent infernos have now transformed the tundra into a net source of carbon dioxide emissions. It’s a dramatic shift for the Arctic, and one that will make the planet even hotter.

The news that the frigid Arctic tundra ringing the polar region has switched from being a net absorber, or "sink," of planet-warming greenhouse gases to a net emitter, or "source," indicates the Arctic is on the brink of further,

Wildfires and thawing permafrost are causing the region to release more carbon dioxide than its plants remove, probably for the first time in thousands of years.

Increasingly frequent and severe wildfires have become a yearly concern for many Arctic communities, and a chapter of a new U.S. report involving one Canadian university—Université de Montréal—suggests that they are also having a significant impact on carbon emissions in the region.

For millennia, Arctic ecosystems have stored more carbon dioxide than they release, but that has shifted as warming temperatures have boosted wildfires and melted permafrost in the north

The shift from storing carbon dioxide to releasing it could have widespread implications for climate change, according to research from the Woodwell Climate Research Center in Falmouth published in NOAA's annual Arctic Report Card.

For millennia, the tundra regions of the Arctic drew in carbon from the atmosphere and locked it in permafrost. That is the case no more, according to an annual report issued on Tuesday by the National Oceanic and Atmospheric Administration.

Wildfires and thawing permafrost are causing the Arctic region to release more carbon dioxide and methane than its plants remove.