The Arctic tundra is undergoing a dramatic transformation, driven by frequent wildfires that are turning it into a net source of carbon dioxide emissions after millennia of acting as a carbon sink, the US National Oceanic and Atmospheric Administration (NOAA) said.
This drastic shift is detailed in NOAA’s 2024 Arctic Report Card, which revealed that annual surface air temperatures in the Arctic this year were the second-warmest on record since 1900.
The Arctic is warming faster than the global average for the 11th year in a row. Currently, it is warming at up to four times the global rate.
Climate warming has dual effects on the Arctic. While it stimulates plant productivity and growth, which remove carbon dioxide from the atmosphere, it also leads to increased surface air temperatures that cause permafrost to thaw.
When permafrost thaws, carbon trapped in the frozen soil is decomposed by microbes and released into the atmosphere as carbon dioxide and methane, two potent greenhouse gases.
Human-caused climate change is also intensifying high-latitude wildfires, which have increased in burned area, intensity and associated carbon emissions.
Wildfires not only combust vegetation and soil organic matter, releasing carbon into the atmosphere, but they also strip away insulating soil layers, accelerating long-term permafrost thaw and its associated carbon emissions.