Recent research has unveiled critical findings regarding the northern permafrost regions, which are warming at an alarming rate, two to four times faster than the global average. Conducted by a team from 35 research institutions, this study provides the first comprehensive greenhouse gas budget for permafrost, revealing its dual role as both a carbon sink and source.
Permafrost, a layer of permanently frozen ground, contains more than a trillion tonnes of carbon—over twice the amount currently in the atmosphere. As climate change causes these frozen landscapes to thaw, they release significant quantities of greenhouse gases, including carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). The study, which covers the years 2000 to 2020, indicates that while permafrost acts as a small to medium CO₂ sink, it simultaneously emits methane and nitrous oxide, complicating its overall impact on global warming.
One of the study’s key findings is the emergence of a negative carbon-climate feedback loop, where increased plant growth due to longer growing seasons and higher nitrogen availability allows for greater carbon accumulation. However, the research also underscores the risks posed by wetlands and wildfires in these regions, which are significant sources of methane emissions.
Looking ahead, the future of greenhouse gas emissions from permafrost remains uncertain. Current trends suggest an increase in methane emissions, with extreme events like wildfires capable of rapidly shifting the carbon balance from sink to source. For instance, the unprecedented wildfires in Siberia and Canada in 2021 and 2023 alone contributed nearly a billion tonnes of carbon emissions, potentially negating the carbon sink effect of permafrost.
To mitigate these risks, the researchers emphasize the urgent need to reduce greenhouse gas emissions from human activities. Without decisive action, the thawing of permafrost could accelerate climate change, leading to a self-reinforcing cycle of warming and emissions.