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.