This Article Free via Open Access: OA Full Text (PDF) Supporting Text Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Canadell, J. G. Articles by Marland, G. Search for Related Content PubMed PubMed Citation Articles by Canadell, J. G. Articles by Marland, G. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB CARBON CARBON BLACK CARBON DIOXIDE Social Bookmarking                What's this?

SUSTAINABILITY SCIENCE
Contributions to accelerating atmospheric CO₂ growth from economic activity, carbon intensity, and efficiency of natural sinks

Josep G. Canadell^a,b, Corinne Le Quéré^c,d, Michael R. Raupach^a, Christopher B. Field^e, Erik T. Buitenhuis^c, Philippe Ciais^f, Thomas J. Conway^g, Nathan P. Gillett^c, R. A. Houghton^h, and Gregg Marland^i,j

^aGlobal Carbon Project, Commonwealth Scientific and IndustrialResearch Organisation Marine and Atmospheric Research, GPO Box 3023, Canberra ACT 2601,Australia; ^cSchool of Environment Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom; ^dBritish Antarctic Survey, Madingley Road,Cambridge CB3 0ET, United Kingdom; ^eDepartment of Global Ecology, Carnegie Institution of Washington, Stanford, CA 94305; ^fLaboratorie des Sciences du Climat et de l'Environnement, Commissariat a L'Energie Atomique, 91191 Gif sur Yvette, France; ^gNational Oceanic and Atmospheric Administration Earth System Research Laboratory, Boulder, CO 80305; ^hWoods Hole Research Center, Falmouth, MA 02540; ⁱCarbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831; and ^jInternational Institute for Applied Systems Analysis, A-2361 Laxenburg, Austria

Edited by William C. Clark, Harvard University, Cambridge, MA, and approved September 17, 2007 (received for review March 27, 2007)

Abstract

The growth rate of atmospheric carbon dioxide (CO₂), the largest human contributor to human-induced climate change, is increasing rapidly. Three processes contribute to this rapid increase. Two of these processes concern emissions. Recent growth of the world economy combined with an increase in its carbon intensity have led to rapid growth in fossil fuel CO₂ emissions since 2000: comparing the 1990s with 2000–2006, the emissions growth rate increased from 1.3% to 3.3% y^–1.The third process is indicated by increasing evidence (P =0.89) for a long-term (50-year) increase in the airborne fraction (AF) of CO₂ emissions, implying a decline in the efficiency of CO₂ sinks on land and oceans in absorbing anthropogenic emissions. Since 2000, the contributions of these three factors to the increase in the atmospheric CO₂ growth rate have been 65±16% from increasing global economic activity, 17±6% from the increasing carbon intensity of the global economy, and 18±15% from the increase in AF. An increasing AF is consistent with results of climate–carbon cycle models, but the magnitude of the observed signal appears larger than that estimated by models.All of these changes characterize a carbon cycle that is generating stronger-than-expected and sooner-than-expected climate forcing.

airborne fraction | anthropogenic carbon emissions | carbon–climate feedback | terrestrial and ocean carbon emissions | vulnerabilities of the carbon cycle

Author contributions: J.G.C., C.L.Q., M.R.R., C.B.F., and P.C. designed research; J.G.C., C.L.Q., M.R.R., C.B.F., E.T.B., P.C., T.J.C., R.A.H., and G.M. performed research; J.G.C., C.L.Q., M.R.R., E.T.B., P.C., T.J.C., N.P.G., R.A.H., and G.M. analyzed data; and J.G.C., C.L.Q., M.R.R., C.B.F., P.C., and R.A.H. wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

^bTo whom correspondence should be addressed. E-mail: pep.canadell{at}csiro.au

CiteULike    Complore    Connotea    Del.icio.us    Digg    What's this?

This article has been cited by other articles in HighWire Press-hosted journals:

				P. S. Auerbach Physicians and the Environment JAMA, February 27, 2008; 299(8): 956 - 958. [Full Text] [PDF]

				W. A. Kurz, G. Stinson, G. J. Rampley, C. C. Dymond, and E. T. Neilson Risk of natural disturbances makes future contribution of Canada's forests to the global carbon cycle highly uncertain PNAS, February 5, 2008; 105(5): 1551 - 1555. [Abstract] [Full Text] [PDF]

				C. Le Quere, C. Rodenbeck, E. T. Buitenhuis, T. J. Conway, R. Langenfelds, A. Gomez, C. Labuschagne, M. Ramonet, T. Nakazawa, N. Metzl, et al. Response to Comments on "Saturation of the Southern Ocean CO2 Sink Due to Recent Climate Change" Science, February 1, 2008; 319(5863): 570c - 570c. [Abstract] [Full Text] [PDF]

				O. Hoegh-Guldberg, P. J. Mumby, A. J. Hooten, R. S. Steneck, P. Greenfield, E. Gomez, C. D. Harvell, P. F. Sale, A. J. Edwards, K. Caldeira, et al. Coral Reefs Under Rapid Climate Change and Ocean Acidification Science, December 14, 2007; 318(5857): 1737 - 1742. [Abstract] [Full Text] [PDF]

				D. Schimel Carbon cycle conundrums PNAS, November 20, 2007; 104(47): 18353 - 18354. [Full Text] [PDF]

Current Issue | Archives | Online Submission | Info for Authors | Editorial Board | About Subscribe | Advertise | Contact | Site Map Copyright © 2007 by the National Academy of Sciences