Rising emissions turning Arctic permafrost into carbon source
24 October 2019 | Adaptation
Arctic regions have captured and stored carbon for tens of thousands of years, but a new study shows winter carbon emissions from the Arctic may now be putting more carbon into the atmosphere than is taken up by plants each year.
We could liken the Arctic permafrost to a ticking time-bomb. While it has remained frozen for thousands of years, the climate crisis has caused it to start thawing. However, the amount of CO2 released from the thawing permafrost in winter is not known and has not been well documented.
Climate scientists until recently, assumed the microbial processes that release the gases from the permafrost as it thaws came to a halt in the cold. However, a new study, supported by NASA ABoVE and conducted in coordination with the Permafrost Carbon Network and more than 50 collaborating institutions from 12 countries, proved the assumption to be wrong.
Researchers found that Arctic soil has warmed to the point where it releases more carbon in winter than northern plants can absorb during the summer. Their findings were published in the prestigious Nature Climate Change journal on October 21, 2019.
To be more specific, the research found that if the world continues with its current "business as usual" way of doing things, winter carbon dioxide loss from the world's permafrost regions could increase by 41 percent. "There's a net loss," said Dalhousie University's Jocelyn Egan. "In a given year, more carbon is being lost than what is being taken in. It is happening already."
The researchers used on-the-ground observations of CO2 emissions to assess current and future winter carbon losses from the northern permafrost regions, placing carbon dioxide monitors along the ground at more than 100 sites around the circumpolar Arctic to see what was actually happening and took more than 1,000 measurements.
The team was able to estimate that the permafrost released an average of 1662 teragrams of carbon each winter from 2003 to 2017 - double that of past estimates. They also looked at other surveys taken during the growing season in the same regions and found that the landscape absorbs only 1032 teragrams—leaving an average of more than 600 teragrams of carbon to escape to the atmosphere each year.
The data shows a loss of 1.7 million metric tons of carbon from the permafrost region during the winter season - which covers October through April. Basically this loss of CO2 is greater than the 1.0 million metric tons of carbon taken up per year.
"Considering the vast amount of land within the world's permafrost regions, it is difficult to gauge how quickly ecosystems are changing. The research resulting from this project could inform government decision-making on climate action to see the impacts of winter warming on the export of carbon under different climatic scenarios" said study co-author Dr. Fereidoun Rezanezhad, University of Waterloo Water Institute & Ecohydrology Research Group member and professor in Earth and Environmental Sciences.
Source: Digital Journal