Permafrost peatlands approach a climate tipping point

Permafrost peatlands in Europe and Western Siberia are much closer to a climatic tipping point than previously thought, according to a new study led by the University of Leeds. Scientists estimate that, even with the strongest efforts to reduce greenhouse emissions and therefore limit climate change, by 2040 the climates of Northern Europe will no longer be cold and dry enough to sustain peat permafrost.

“Peatland permafrost responds differently to changing climates than mineral-soil permafrost due to the insulating properties of organic soils, but peatlands remain poorly represented in Earth system models,” said study co-author Dr. Ruza Ivanovic, an associate professor of Climatology at Leeds. “It is vitally important these ecosystems are understood and accounted for when considering the impact of climate change on the planet.”

By using the latest generation of climate models to examine possible future climates of these regions, the scientists found that global warming will most likely cause massive permafrost melting, and subsequent release of the huge quantities of carbon dioxide that are stored in these frozen peatlands (about 39 billion tons of carbon – the equivalent to twice that stored in all the European forests).

“We examined a range of future emission trajectories. This included strong climate-change mitigation scenario, which would see large-scale efforts to curb emissions across sectors, to no-mitigations scenarios and worse-case scenarios,” said study lead author Richard Fewster, a PhD student in Geography at Leeds.

“Our modelling shows that these fragile ecosystems are on a precipice and even moderate mitigation leads to the widespread loss of suitable climates for peat permafrost by the end of the century.”

“But that doesn’t mean we should throw in the towel,” he stressed. “The rate and extent to which suitable climate are lost could be limited, and even partially reversed, by strong climate-change mitigation policies.”

Such strong action to reduce greenhouse emissions could help preserve suitable climates for permafrost peatlands at least in the northern parts of Western Siberia, a region where 13.9 billion tons of carbon are stored. 

These projections emphasize the importance of socio-economic policies aimed at reducing emissions and mitigating climate change. Further research is needed to improve maps of modern peat permafrost distribution in areas where observation data is lacking and thus to enable future modelling studies able to make hemispheric-scale projections.

The study is published in the journal Nature Climate Change.  

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By Andrei Ionescu, Earth.com Staff Writer