North America's net terrestrial CO2 exchange with the atmosphere 1990-2009
Scientific understanding of the global carbon cycle is required for developing national and international policy to mitigate fossil fuel CO2 emissions by managing terrestrial carbon uptake. Toward that understanding and as a contribution to the REgional Carbon Cycle Assessment and Processes (RECCAP) project, this paper provides a synthesis of net land-atmosphere CO2 exchange for North America (Canada, United States, andMexico) over the period 1990-2009. Only CO2 is considered, not methane or other greenhouse gases. This synthesis is based on results from three different methods: atmospheric inversion, inventory-based methods and terrestrial biosphere modeling. All methods indicate that the North American land surface was a sink for atmospheric CO2, with a net transfer from atmosphere to land. Estimates ranged from −890 to −280 TgC yr−1, where the mean of atmospheric inversion estimates forms the lower bound of that range (a larger land sink) and the inventory-based estimate using the production approach the upper (a smaller land sink). This relatively large range is due in part to differences in how the approaches represent trade, fire and other disturbances and which ecosystems they include. Integrating across estimates, "best" estimates (i.e., measures of central tendency) are −472±281 TgC yr−1 based on the mean and standard deviation of the distribution and −360 TgC yr−1 (with an interquartile range of −496 to −337) based on the median.
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Texto biblioteca |
| Language: | eng |
| Subjects: | Ciclo del carbono (Biogeoquímica), Suelos, Artfrosur, |
| Online Access: | http://www.biogeosciences.net/12/399/2015/bg-12-399-2015.pdf |
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