Climate Science

A Question of Balance

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Science  03 Jan 2014:
Vol. 343, Issue 6166, pp. 7
DOI: 10.1126/science.343.6166.7-b

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Arctic permafrost is thought to contain twice as much carbon as the atmosphere. As climate warming causes increasing amounts of that permafrost to melt, release of carbon as methane or carbon dioxide (CO2) may cause additional, rapid warming. However, it is likely that at least some of the carbon made available by permafrost melting will be used by the vegetation that is appearing in warming regions, but how large a sink that may be is unknown. Lupascu et al. report that in High Arctic tundra—an important subset of permafrost terrain, which is experiencing a complex combination of rising temperatures, increasing precipitation, and permafrost degradation—warming alone decreases the summertime CO2 sink strength by up to 55%, but warming combined with wetting increased the CO2 sink strength by an order of magnitude. Thus, the High Arctic has the potential to remain a strong carbon sink even if the rest of the Arctic permafrost region becomes a net carbon source due to future global warming.

Nat. Clim. Change 10.1038/NCLIMATE2058 (2013).

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