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Arctic shifts to carbon source – stunning turnaround after carbon capture for tens of thousands of years



  ASCENDS Campaign Nome Alaska

The Night, Days, and Seasons (ASCENDS) Active Carbon Campaign flew over Nome, Alaska, on August 5, 201

7 as part of NASA's Arctic Combat Vulnerability Experiment ( ABoVE). Credit: NASA

A NASA-funded study suggests that winter carbon emissions in the Arctic may add more carbon to the atmosphere each year than that absorbed by Arctic vegetation, which is a terrific reversal for a region that has captured and stored carbon for ten for thousands of years.

A study published on October 21, 2019, in Climate Change in Nature warns that the loss of carbon dioxide in winter by global freezing regions can increase by 41% in the next century, if human emissions of greenhouse gases continue at their current rates. Carbon separated from the freezing of permafrost has not been included in most models used to predict future climate.

Eternal freezing is a carbon-rich frozen soil that covers 24% of the land area of ​​the Northern Hemisphere, covering vast stretches of territory in Alaska, Canada, Siberia and Greenland. Permafrost retains more carbon than it has ever released from humans through the burning of fossil fuels, and this perpetual freezing has kept carbon safely enclosed in an ice embrace for tens of thousands of years. But as global temperatures warm, eternal freezing thaws and releases greenhouse gases into the atmosphere.

"These findings indicate that the loss of carbon dioxide in the winter can now offset the absorption of carbon during the season and these losses will increase as the climate continues to warm," said Woods Hole Sue, director of research Natalie, lead author of the study. "Site-focused studies have undergone this transition, but so far we have not had a clear record of winter carbon balance across the Arctic region."

  Alaskan Permafrost

Deep-sea, often freezing, thousands of years deep in Alaskan Hill called the "fossil glaciers" of the cryosphere. Credit: NASA / Jefferson Beck

This study was supported by the NASA Arctic Salt Vulnerability Experiment (ABoVE) and coordinated with Permafrost's carbon network and over 50 collaborating institutions. In addition to space observations of the changing environment of the Earth, NASA is sponsoring scientific field campaigns to improve our understanding of how our climate is changing and may change in the future.

Researchers have field-monitored carbon dioxide emissions from many sites and combined them with remote sensing data and ecosystem models to evaluate current and future carbon losses in winter for northern regions of eternal freezing. They estimate an annual loss of 1.7 billion metric tonnes of carbon from the region of permafrost in the winter season from 2003 to 2017, compared to the estimated average of 1 billion metric tonnes of carbon absorbed during the growing season.

To extend model predictions For warmer conditions in 2100, the climate predicted for different scenarios of future fossil fuel emissions is used to calculate the effect on permafrost. If fossil fuel consumption is moderately reduced in the next century, winter carbon dioxide emissions will increase by 17% compared to current emissions. In a scenario where the use of fossil fuels continues to increase at a steady pace during the middle of the century, winter carbon dioxide emissions from permafrost would increase by 41%.

"The warmer it is, the more carbon will be released into the atmosphere from the permafrost region, which will contribute to further warming," said co-author Brendan Rogers, a climatologist at the Woods Hole Research Center. "This is due to the fact that our study, which uses many more observations than ever, shows a much stronger Arctic carbon source in winter. We may witness a transition from annual carbon sequestration in the Arctic to a carbon source, which is not good news. "

Climate modeling teams around the world are trying to incorporate processes and dynamic events that affect the carbon emissions of permafrost. For example, thermal-karst lakes formed by melting ice can accelerate the rate of carbon dioxide emissions by exposing deeper layers to freezing at warmer temperatures. Likewise, Arctic and boreal forest fires, which are becoming more frequent and severe, can eliminate the insulating topsoil, accelerating and deepening the freezing of eternal freezing.

"These interactions are not yet taken into account in most models, and undoubtedly. increasing carbon emissions from permafrost regions, "said Rogers.

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Reference:" Great CO loss 2 in winter observed in northern permafrost region " by Susan M. Natali, Jennifer D. Watts, Brandon M. Rogers, Stefano Potter, Sarah M. Ludwig, Anne-Catherine Selbman, Patrick F. Sullivan, Benjamin W. Abbott, Kyle A. Arnd, Lee Birch, Mats P. Bjorkman, A. Anthony Bloom, Gerardo Selis, Torben R. Christensen, Casper T. Christiansen, Roazin Coman, Elizabeth J. Cooper, Patrick Creel, Claudia Zimtsik, Sergey Davidov, Ginyang y, Jocelyn E. Egan, Bo Elberling, Eugene S. Eskirchen, Thomas Friborg, Hélène Genet, Mathias Göckede, Jordan P. Goodrich, Paul G Rogan, Manuel Helbig, Elchin E. Jafarov, Julie D. Jastrow, Aram A.M. Kalhori, Yongong Kim, John S. Kimball, Lars Kutzbach, Mark J. Lara, Klaus S. Larsen, Bang-Jong Lee, Jihua Liu, Michael M Guarantee, Magnus Lund, Massimo Lupasu, Nima Madani, Avni Malhotra, Rozer Matamalah , Jack McFarland, A. David McGuire, Anders Michelsen, Christina Minions, Walter K. Oichel, David Olefeld, France-Jan W. Parmentier, Norbert Pirk, Ben Poulter, William Quinton, Fereidoun Rezanezhad, David Risk, Torsten Sachs, Kevin Schaefer, Niels M. Schmidt, Edward A. G. Schuur, Philipp R. Semenchuk, Gaius Shaver, Oliver Sonnentag, Gregory Starr, Claire C. Treat, Mark P. Waldrop, Yihui Wang, Jeffrey Welker, Christian Wille, Xiaofeng Xu, Zhen Zhang. Qianlai Zhuang and Donatella Zona, October 21, 2019, Climate Change in Nature .
doi: 10.1038 / s41558-019-0592-8


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