Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2007 Nov 20;104(47):18866-70.
doi: 10.1073/pnas.0702737104. Epub 2007 Oct 25.

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

Josep G Canadell  1 , Corinne Le Quéré, Michael R Raupach, Christopher B Field, Erik T Buitenhuis, Philippe Ciais, Thomas J Conway, Nathan P Gillett, R A Houghton, Gregg Marland
Affiliations

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

Josep G Canadell et al. Proc Natl Acad Sci U S A. .

Abstract

The growth rate of atmospheric carbon dioxide (CO(2)), 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 CO(2) 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 CO(2) emissions, implying a decline in the efficiency of CO(2) sinks on land and oceans in absorbing anthropogenic emissions. Since 2000, the contributions of these three factors to the increase in the atmospheric CO(2) growth rate have been approximately 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.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Fossil-fuel intensity of the GWP from 1970 to 2006 (A) and the CO2 budget from 1959 to 2006 (B). Fossil-fuel intensity uses GWP data based on market exchange rates, expressed in U.S. dollars (referenced to 1990, with inflation removed). (B Upper) CO2 emissions to the atmosphere (sources) as the sum of fossil fuel combustion, land-use change, and other emissions, which are primarily from cement production. (Lower) The fate of the emitted CO2, including the increase in atmospheric CO2 plus the sinks of CO2 on land and in the ocean. Flux is in Pg y−1 carbon (left axis) and Pg y−1 CO2 (right axis).
Fig. 2.
Fig. 2.
Fraction of the total emissions (FFoss + FLUC) that remains in the atmosphere (A), the land biosphere (B), and the ocean (C).
See this image and copyright information in PMC

Comment in

  • Carbon cycle conundrums.
    Schimel D. Schimel D. Proc Natl Acad Sci U S A. 2007 Nov 20;104(47):18353-4. doi: 10.1073/pnas.0709331104. Epub 2007 Nov 12. Proc Natl Acad Sci U S A. 2007. PMID: 17998533 Free PMC article. No abstract available.

References

    1. Sabine CL, Heimann M, Artaxo P, Bakker DCE, Chen C-TA, Field CB, Gruber N, Le Quéré C, Prinn RG, Richey JE, et al. In: Global Carbon Cycle: Integrating Humans, Climate and the Natural World. Field C, Raupach MR, editors. Washington, DC: Island Press; 2004. pp. 17–44.
    1. Canadell JG, Pataki D, Gifford R, Houghton RA, Lou Y, Raupach MR, Smith P, Steffen W. In: Terrestrial Ecosystems in a Changing World. Canadell JG, Pataki D, Pitelka L, editors. Berlin: Springer; 2007. pp. 59–78.
    1. Raupach MR, Marland G, Ciais P, Le Quéré C, Canadell JG, Klepper G, Field CB. Proc Natl Acad Sci USA. 2007;104:10288–10293. - PMC - PubMed
    1. Buermann W, Lintner BR, Koven CD, Angert A, Pinzon JE, tucker CJ, Fung IY. Proc Natl Acad Sci USA. 2007;104:4249–4254. - PMC - PubMed
    1. Petit JR, Jouzel J, Raynaud D, Barkov NI, Barnola JM, Basile I, Bender M, Chappellaz J, Davisk M, Delaygue G, et al. Nature. 1999;399:429–436.

Publication types