NEWS Permafrost soils store large quantities of frozen carbon, which are important for the global climate. As permafrost thaws these soils warm up and release previously frozen carbon, as well as at the same time form new lakes. A study published in Nature Communications, led by researchers from the Climate Impacts Research Centre (CIRC) at Umeå University, Sweden, shows that greenhouse gas emissions from permafrost-affected lakes of Western Siberia are high, but might decrease as permafrost thaws.
As climate warms and permafrost thaws, previously frozen carbon can end up in lakes where it will be processed and emitted as greenhouse gases from the water surface directly into the atmosphere. At the same time, climate warming and thawing permafrost create new lakes, that become an increasingly abundant landscape feature in the permafrost-affected regions across the Arctic. Quantifying greenhouse gas emissions from permafrost-affected lakes is important and especially in such areas as Western Siberia with large carbon stocks stored in region’s rapidly warming permafrost.
Now researchers from Umeå University and collaborators from SLU, Russia and France have shown that lake greenhouse gas emissions are high in the areas where Western Siberian permafrost is most stable, but decrease in areas where permafrost is actively degrading. The research team has also found out that greenhouse gas emissions from permafrost-affected lakes of Western Siberia exceed the amount of carbon this region transports to the Arctic coast.
“This finding means that permafrost-affected lakes of Western Siberian release large part of the previously frozen carbon they receive from thawing permafrost and that the magnitude of these emissions might decrease with climate warming” says Svetlana Serikova, doctoral student in the Department of Ecology and Environmental sciences, Umeå University, and one of the researchers in the team.
Quantifying lake greenhouse gas emissions from areas where permafrost is widespread and is rapidly thawing is important as it improves our knowledge how these climate-sensitive areas respond to a warming climate.
“Lake greenhouse gas emissions represent an important feedback to the warming climate, and it has been generally assumed that warming would further accelerate these emissions because of increased decomposition in lakes. But as our results suggest the magnitude of greenhouse gas emissions from permafrost-affected lakes might decrease as permafrost degrades since warming and thawing also trigger other processes capable of counteracting these negative effects. The degree to which these counteracting processes are capable to balance adverse impact of thawing permafrost is a knowledge gap and needs to be explored further ” says Svetlana Serikova.
S. Serikova, O.S. Pokrovsky, H. Laudon, I.V. Krickov, A.G. Lim, R.M.Manasypov and J. Karlsson, High carbon emissions from thermokarst lakes of Western Siberia, Nature Communications, DOI 10.1038/s41467-019-09592-1. https://www.nature.com/articles/s41467-019-09592-1