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



Campaign ASCENDS Name Alaska

Campaign for Active Sense of Carbon Emissions over Nights, Days and Seasons (ASCENDS) The campaign flew over Nome, Alaska, on August 5, 2017, as part of NASA's Arctic Vulnerability Experiment. Credit: NASA

A NASA-funded study suggests that winter carbon emissions in the Arctic can add more carbon to the atmosphere each year than it does to Arctic vegetation, signaling a strong turnaround for a region that captures and stores carbon for tens of thousands of years.

The study, published on October 21, 2019, in Climate change in nature, warns that loss of winter carbon dioxide from the world's most transient regions could increase by 41% over the next century if human-greenhouse gas emissions continue at their current pace. Melting carbon released from melting performance is not included in most models used to predict future climate conditions.

Permafrost is a frozen carbon-rich soil that covers 24% of the northern hemisphere's surface, covering vast tracts of territory across Alaska, Canada, Siberia and Greenland. Permfrost holds more carbon than humans have ever released through the burning of fossil fuels, and this permafrost keeps carbon locked securely in a hug for tens of thousands of years. But as global temperatures warm, permafrost melts and releases greenhouse gases into the atmosphere.

"These findings suggest that loss of winter carbon dioxide may already offset the carbon uptake in the growing season and these losses will increase as the climate continues to warm," said Woods Hole Arctic Research Center Program Director Sue Natalie, lead author of the study. "Studies focused on individual sites have noted this transition, but until now we had no clear accounting for the winter carbon balance across the Arctic region."

Alaska Permafrost

The deep part of the Alaskan hillside reveals thousands of years of weakness, often called "fossilized glaciers" of the cryosphere. Credit: NASA / effeferson Beck

This study was supported by the Arctic-Boreal Vulnerability Experiment (HAD) and was conducted in coordination with the Permfrost Carbon Network and more than 50 institutions in collaboration. In addition to space-based observations of the changing environment of the Earth, NASA sponsors scientific field campaigns to advance our understanding of how our climate is changing and may change in the future.

Researchers have compiled extensive carbon dioxide emissions monitoring in many places and combined them with remote sensing data and ecosystem models to estimate the current and future carbon losses during winter for the northern regions of the wider area. They estimate an annual loss of 1.7 billion metric tonnes of carbon from the permafrost region during the winter season from 2003 to 2017 over the estimated average value of 1 billion metric tonnes of carbon taken over the growing season.

To extend the predictions of models in warmer conditions in 2100, the climate predicted for different scenarios of future fossil fuel emissions was used to calculate the effect on permafrost. If the use of fossil fuels is modestly reduced over the next century, winter carbon dioxide emissions would increase by 17% compared to current emissions. Under a scenario where the use of fossil fuels continues to increase at current rates throughout the middle of the century, winter carbon dioxide emissions from permprost will increase by 41%.

"The hotter it is, the more carbon will be released into the atmosphere from the permafrost region, which will add to further warming," said co-author Brendan Rodgers, climate scientist at Woods Research Center. "It is worrying that our study, which used much more refinements than ever before, points to a much stronger Arctic carbon source in the winter. "Maybe we are witnessing the transition from an annual Arctic sink to a carbon source, which is not good news."

Climate modeling teams around the world are trying to incorporate processes and dynamic events affecting permafrost carbon emissions. For example, thermocarbon lakes formed by melting ice can accelerate the rate of carbon dioxide emission by exposing deeper layers of permafrost to warmer temperatures. Arctic fires and forests, which are becoming more frequent and serious, can also remove the insulating topsoil, accelerating and deepening the permafrost thaw.

"These interactions are not yet considered by most models and will undoubtedly increase carbon emissions estimates from regions with the province," Rogers said.

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Reference: "Big loss of CO2 in winter observed through the northern Permafrost region ”by Susan M. Natalie, Ennifer D. Watts, Brendan M. Rogers, Stefano Potter, Sarah M. Ludwig, Anne-Catherine Selbman, Patrick F. Sullivan, Benjamin W. Abbott, Kyle A. . Arndt, Leah Birch, Mats P. Björkman, A. Anthony Bloom, Gerardo Celis, Torben R. Christensen, Casper T. Christianen, Roisin Commane, Elisabeth J. Cooper, Patrick Crill, Claudia Cimczik, Sergey Davydov, Jinyang Du, Jocelyn E Egan, Bo Elberling, Eugenie S. Euskirchen, Thomas Friborg, Hélène Genet, Mathias Göckede, Jordan P. Goodrich, Paul Grogan, Manuel Helbig, Elchin E. Jafarov, Julie D. Jastrow, Aram A. Kalhori, Yongwon Kim, John S. . Kimball, Lars Kutbach, Mark J. Lara, Claus S. Larsen, Bang-Jong Lee, Iihua Lee, Michael M. Lorentz, Magnus Lund, Massimo Lupascu, Nima Madani, Avni Malchotra, Roser Matamala, Jack McHarland, A. David McGuire, Anders Mikkelsen, Christina Mignons, Walter H. Oehel, David Olefeld, France-Jean W. Parmentier, Norbert Pirk, Ben Polter, William Quinton, Fereidoun Rezanezhad, David Risk, Thorsten Sachs, Kevin Schaefer, Nils M. Schmidt, Edward AG Shoor, Philip R. Semenchuk, Gaius Javert, Oliver Sonontag, Gregory Star, Claire W. , Effeferi Welker, Christian Will, Xiaofeng Xu, henen angang, Qianlai uangang and Donatella Zone, October 21, 2019, Climate change in nature.
DOI: 10.1038 / s41558-019-0592-8


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