GC12B-03
The State of the Carbon Cycle: Ten Years On
Monday, 14 December 2015: 10:30
3014 (Moscone West)
Anthony W King1, Lisa Dilling2, David M Fairman3, Richard A Houghton4, Gregg Marland5, Adam Rose6, Thomas J Wilbanks1 and Gregory Zimmerman1, (1)Oak Ridge National Laboratory, Oak Ridge, TN, United States, (2)University of Colorado at Boulder, Western Water Assessment RISA, Boulder, CO, United States, (3)Consensus Building Institute, Cambridge, MA, United States, (4)Woods Hole Research Center, Falmouth, MA, United States, (5)Appalachian State University, Boone, NC, United States, (6)University of Southern California, Los Angeles, CA, United States
Abstract:
It has been nearly ten years since the First State of the Carbon Cycle Report (SOCCR-1) was published in 2007. Much has changed in the intervening years, but much has remained the same. In anticipation of a Second State of the Carbon Cycle Report (SOCCR-2), we, the members of the SOCCR-1 Coordinating Team, felt that a perspective from the first SOCCR and reflection on changes in the state of carbon cycle science and policy in the intervening years would be appropriate. The purpose of SOCCR-1 was to provide “…a synthesis and integration of the current knowledge of the North American carbon budget and its context within the global carbon cycle [i]n a format useful to decision makers.” Being “useful to decision makers” was a guiding theme with three stakeholder workshops an integral part of the process. Drafting and revision of SOCCR-1 took place between 2005 and early 2007; the report’s carbon budget was for circa 2003. In 2003, North America’s fossil-fuel CO2 emissions were approximately 27% of global emissions. Nearly 85% of North American emissions were from the US, still at that time the world’s largest emitter of fossil-fuel CO2. China’s annual CO2 emissions exceeded those of the US for the first time while SOCCR-1 was being written. Today global CO2 emissions are dominated by emissions from China (28% in 2013), with US emissions only 14% of global emissions. Emissions from the US and North America have actually declined by approximately 10% since 2003 while emissions from China have doubled. Based on inventories of terrestrial carbon stocks, SOCCR-1 estimated that circa 2003 North American vegetation removed and stored a net 500 Mt C y-1 (±50%) from the atmosphere. A more recent synthesis incorporating additional estimates from atmospheric inversions and terrestrial biosphere modeling estimated the North American land sink for the decade of 2000-2009 at 350-470 Mt C y-1, with a slightly greater uncertainty due to the wider range of estimates from the different methods. Equally important are changes in the landscape of carbon cycle management and policy since SOCCR-1. These changes, including US Supreme Court decisions on the regulation of greenhouse gases, the 2014 US-China agreement on limiting emissions, and California’s cap-and-trade program, provide the context for a SOCCR-2 that is “…useful to decision makers.”
