Land carbon sequestration within the conterminous United States: Regional‐ and state‐level analyses. Issue 2 (28th February 2015)

• Record Type: Journal Article
• Authors: Lu, Xiaoliang; Kicklighter, David W.; Melillo, Jerry M.; Reilly, John M.; Xu, Liyi
• Is Part Of: Journal of geophysical research. Volume 120:Issue 2(2015:Apr.)
• Page Start: 379
• Page End: 398
• Publication Date: 2015-02-28
• Subjects: carbon cycle -- land carbon sinks -- land use and land cover change -- stand age -- fossil fuel emissions -- land use legacies; Geobiology -- Periodicals; Biogeochemistry -- Periodicals; Biotic communities -- Periodicals; Geophysics -- Periodicals; 577.14
• DOI: 10.1002/2014JG002818
• Languages: English
• ISSNs: 2169-8953

Abstract

Abstract: A quantitative understanding of the rate at which land ecosystems are sequestering or losing carbon at national‐, regional‐, and state‐level scales is needed to develop policies to mitigate climate change. In this study, a new improved historical land use and land cover change data set is developed and combined with a process‐based ecosystem model to estimate carbon sources and sinks in land ecosystems of the conterminous United States for the contemporary period of 2001–2005 and over the last three centuries. We estimate that land ecosystems in the conterminous United States sequestered 323 Tg C yr −1 at the beginning of the 21st century with forests accounting for 97% of this sink. This land carbon sink varied substantially across the conterminous United States, with the largest sinks occurring in the Southeast. Land sinks are large enough to completely compensate fossil fuel emissions in Maine and Mississippi, but nationally, carbon sinks compensate for only 20% of U.S. fossil fuel emissions. We find that regions that are currently large carbon sinks (e.g., Southeast) tend to have been large carbon sources over the longer historical period. Both the land use history and fate of harvested products can be important in determining a region's overall impact on the atmospheric carbon budget. While there are numerous options for reducing fossil fuels (e.g., increase efficiency and displacement by renewable resources), new land management opportunities for sequestering carbon need to be explored. Opportunities include reforestation and managing forest age structure. These opportunities will vary from state to state and over time across the United States. Key Points: A new land use and land cover data set for the conterminous U.S. is created State, regional, and national land carbon sinks and sources are estimated Possible policies to enhance carbon sinks are discussed