Permafrost is a permanently frozen layer below the Earth’s surface that is found in arctic regions such as Alaska, Siberia, and Canada. It usually consists of soil, gravel, and sand held together by ice. It is ground that remains frozen all year . However, it is facing an invisible threat with rapid melting due to climate change.
Now, using state-of-the-art climate models, a team of scientists has examined the possible future climates of these regions, finding that global warming will most likely cause massive melting of permafrost and subsequent release of huge amounts of carbon dioxide that are stored in these frozen peat bogs.
Thus, permafrost peatlands in Europe and western Siberia are much closer to a climate tipping point than previously thought, according to a new study led by the University of Leeds (UK) and published in the journal Nature Climate Change.
Scientists estimate that, even with our best efforts to reduce greenhouse gas emissions and thus limit climate change, by the 2040 date the climates of northern Europe will not be sufficiently cold and dry enough to support peat permafrost. The consequence? That peatlands could release up to 39 billion tons of carbon , the equivalent of twice the amount of carbon stored in all European forests.
Greenhouse gases released into the atmosphere by thawing permafrost act as a positive feedback, further increasing warming. Although carbon loss from thawing permafrost is irreversible, stopping warming can slow and potentially stop further thawing.
“Peatland permafrost responds differently to changing climates than mineral soil permafrost due to the insulating properties of organic soils, but peatlands continue to be poorly represented in Earth system models,” says Ruza Ivanovic, Professor Associate of Climatology in Leeds and co-author of the study. “It is vitally important that these ecosystems are understood and taken into account when considering the impact of climate change on the planet.”
Mitigate climate change
Global warming is causing frozen peatlands to melt and release greenhouse gases into the atmosphere. The scientists’ new projections suggest that taking significant steps to address global warming could help preserve the right climate for permafrost peatlands in northern Western Siberia.
“Our model shows that these fragile ecosystems are on the edge of the precipice and even moderate mitigation leads to widespread loss of climates suitable for peat permafrost by the end of the century,” says Richard Fewster, lead of the work.
“Freezing conditions have protected huge peat carbon stores for millennia, but once those conditions become unsuitable, all the stored carbon can be lost very quickly ,” says Paul Morris, also of the University of Leed.
Melting permafrost causes greenhouse gas emissions
This frozen layer traps billions of tons of carbon dioxide and methane. The sudden melting of similar areas about 55 million years ago is thought to have triggered the Paleocene-Eocene Thermal Maximum, when temperatures rose sharply in just a few thousand years. Now the permafrost is melting again.
Until a few years ago, no one believed that all or most of the amount it stores would melt. If this frozen Pandora’s box were opened, it could wreak untold havoc on our planet.
According to experts, more research is needed to improve maps of the modern distribution of peat permafrost in areas where observational data are lacking, and thus enable future modeling studies capable of making hemispheric-scale projections.
Referencia: Richard Fewster, Imminent loss of climate space for permafrost peatlands in Europe and Western Siberia, Nature Climate Change (2022). DOI: 10.1038/s41558-022-01296-7. www.nature.com/articles/s41558-022-01296-7
