Permafrost, a frozen layer of soil rich in organic matter, lies beneath 15 percent of the northern hemisphere and is facing significant degradation due to rising global temperatures. According to findings published in Earth’s Future, researchers predict extensive thawing of permafrost by the end of this century. This thawing, influenced by the intensifying greenhouse effect, raises concerns about the volume of carbon dioxide that could be released into the atmosphere, potentially exacerbating climate change.
Study Findings on Thawing Scenarios
The work, by four scientists in China and one at Purdue University in the US, is published in the journal Earth’s Future. Researchers led by Lei Liu of Zhengzhou University in China, alongside collaborators from Purdue University, utilised a process-based biogeochemical model for their analysis. The model incorporated observational data and deeper soil layers, offering insights into carbon exposure from permafrost thaw, as per reports. Their assessment spanned two Shared Socioeconomic Pathways (SSPs): SSP126, limiting warming to 2 degree Celsius, and SSP585, depicting high fossil fuel reliance.
Reportedly, under SSP126, it is projected that 119 gigatons (Gt) of carbon will thaw by 2100, while the SSP585 scenario could see 252 Gt of carbon becoming available. Of this, only 4 percent to 8 percent is expected to enter the atmosphere, equating to a maximum of 20 Gt. These figures align with estimates reported in 2015, suggesting that permafrost-related emissions may remain relatively moderate this century.
Impacts on Vegetation and Climate Dynamics
The study highlighted potential changes in ecosystem dynamics due to thawing permafrost. Decomposing organic matter could increase nitrogen availability, enhancing plant growth. Carbon storage in vegetation may rise by up to 1.6 Gt under SSP585, partially offsetting carbon losses.
Uncertainties remain, especially in high-latitude regions, where abrupt thaw and microbial activity could accelerate carbon release. As researchers emphasise, the trajectory of these changes depends heavily on global mitigation efforts and socio-economic decisions over the coming decades.
For long-term climate stability, reductions in human-induced emissions are deemed essential to minimise permafrost degradation and its feedback effects on global warming.