Earlier snowmelt causing knock-on effects for Arctic carbon

Earlier snowmelt and Arctic greening are affecting carbon sequestration later in the year in northern Arctic regions, according to a new study from a scientist at the University of Sheffield.

Tundra research site in Ivotuk, Alaska
  • Arctic warming is causing earlier snowmelt and longer growing seasons in Arctic tundra ecosystems
  • It was previously believed that this would cause an increase in carbon sequestration in these regions - an increase in the amount of carbon captured and stored in Arctic vegetation, potentially slowing down global warming
  • New research has found that earlier snowmelt actually causes a loss in net carbon sequestration later in the year

Earlier snowmelt and Arctic greening are affecting carbon sequestration later in the year in northern Arctic regions, according to a new study from a scientist at the University of Sheffield. 

The new research has found that earlier snowmelt and a longer growing season, caused by climate change, are not causing a consistent increase in carbon sequestration as first thought. 

It has long been assumed that this longer period of growth and plant productivity would lead to an increase in the summer carbon sequestration, the process of capturing and storing atmospheric carbon. 

The findings published in Scientific Reports, however, show that whilst there is an increase in carbon sequestration during June and July, it leads to a loss in net carbon sequestration later in the season around August time. 

A member of the research team checking tundra monitoring instruments in Ivotuk, Alaska

Dr Donatella Zona, from the University of Sheffield’s School of Biosciences and the Department of Biology at San Diego State University and lead author of the research, said: “Climate change is having a major impact on the Arctic and Arctic warming, earlier snowmelt and Arctic greening are causing changes to the atmospheric carbon there. 

“Our results show that the expected increased CO2 sequestration arising from Arctic warming and the associated increase in growing length may not materialise if tundra ecosystems are not able to continue capturing CO2 later in the season. 

“The results should be considered when predicting the overall response of the Arctic carbon balance to climate change.”

The study was carried out using an extensive dataset from 11 sites in Arctic tundra ecosystems across Alaska, Canada, Greenland and Russia, allowing researchers to test the response of a wide range of sites to the earlier snowmelt. 

The research, Earlier snowmelt may lead to late season declines in plant productivity and carbon sequestration in Arctic tundra ecosystems, is published in Scientific Reports. Read the paper in full.

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