Rivers are a significant source of greenhouse gas emissions in Arctic areas

Rivers in Arctic areas constitute a significant source of greenhouse gas emissions, and especially of carbon dioxide emissions. An international research project has found that the amount of carbon being released from rivers into the atmosphere is larger than previously estimated in the world’s most extensive peat regions in Western Siberia. As the climate warms up, the melting permafrost exposes the huge peat areas in the region, and the organic carbon within this peat can then escape into the atmosphere and accelerate climate change.

“A significant proportion of natural greenhouse gas emissions in northern regions come from surface waterways. The most recent research has indicated that rivers are not simply ‘pipes’ that carry carbon from the land to the sea, but are actually also releasing it into the atmosphere. The exact quantities are not known because little research has been carried out and few measurements have been made”, explains Research Fellow Pertti Ala-aho from the University of Oulu, who participated in the project.

According to the research, the amount of carbon being released from Western Siberian rivers into the atmosphere was on average two times larger than the quantity of carbon being carried within the waters of the rivers. In addition, carbon dioxide emissions from the rivers were observed to be at their highest on the borders of the areas of melting permafrost – as much as 3 to 5 times higher than in the areas of sustained permafrost. Based on the research, the rivers in the areas of melting permafrost would seem to be larger sources of greenhouse gases than other Arctic rivers.

“As the permafrost melts, we can expect emissions to increase from both the landmass and the river systems. Surface waterways are hotspots for greenhouse gases – it is clear that more carbon dioxide is released for a given area from waterways compared to areas of solid terrain. Our results suggest that carbon dioxide emissions from rivers are influenced by both temperature and also the hydrological changes caused by the melting permafrost”, Mr Ala-aho continues. As part of the project, he worked out the impact of permafrost on water current routes by studying the water´s isotope composition.

The results of the Climate impact on the carbon emission and export from Siberian inland waters research project were published in Nature Geoscience on 3 September 2018.

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Main photo: Tomsk State University, Sergey Vorobyev

Last updated: 13.9.2018