Arctic now a source of carbon dioxide, say scientists

The Arctic tundra, long considered a vital carbon sink, is potential undergoing a dramatic transformation into a source of carbon dioxide, new reports suggest. 

Arctic temperatures in 2024 ranked as the second-warmest on record since 1900, underscoring the severity of the region's warming trend. 

As the frozen soil melts, microbes decompose organic matter trapped in permafrost, releasing significant quantities of carbon dioxide and methane. 

Why is Arctic permafrost melting? 

According to the US National Oceanic and Atmospheric Administration (NOAA), the Arctic is warming up to four times faster than the global average. 

Simultaneously, more intense circumpolar wildfires (i.e., fires in Canada, Scandinavia and Siberia) are accelerate permafrost thaw by removing insulating soil layers. 

Besides this thawing, circumpolar wildfires have themselves released an average of 207 million tons of carbon annually, since 2003. 

NOAA Administrator Dr. Rick Spinrad: “Our observations now show that the Arctic tundra, which is experiencing warming and increased wildfire, is now emitting more carbon than it stores”. 

How does a net-emitting Arctic impact the climate? 

For millennia, the Arctic acted as a buffer against rising atmospheric carbon levels by sequestering greenhouse gases in its permafrost, peatlands and tundra flora. 

Therefore, our capacity to sequester carbon after we reach net-zero emissions has been (potentially) permanently reduced, constraining our ability to avoid further warming.  

Relatedly, a warmer Arctic disrupts the jet stream and AMOC, effecting atmospheric shifts that will lead to more frequent famines. 

Biodiversity loss in the Arctic tundra 

Arctic caribou population fell by 65% in recent decades, as freezing rain creates ice that conceals lichen, their primary food source.  

In the Arctic’s marine systems, warmer conditions are disrupting entire ecologies by shrinking sea ice, reducing salinity, altering plankton blooms, and warming oceans. 

As a result, the food security of communities in the Arctic Circle is greatly reduced – and will, in all likelihood, plunge much further, prompting migrations. 

Monitoring needed to forecast and intervene 

Scientists have stressed the need for accurate and comprehensive data to quantify emissions, predict future changes and guide intervention.  

Collaborative approaches, integrating Indigenous knowledge with conventional scientific research, are crucial for developing effective adaptation and mitigation strategies. 

However, permafrost thawing is largely self-sustaining, permitting little intervention. In a sense, then, all we can do is measure the damage.