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Philos Trans R Soc Lond B Biol Sci. 2004 March 29; 359(1443): 331–343.
PMCID: PMC1693328

Tropical forests and the global carbon cycle: impacts of atmospheric carbon dioxide, climate change and rate of deforestation.


The remaining carbon stocks in wet tropical forests are currently at risk because of anthropogenic deforestation, but also because of the possibility of release driven by climate change. To identify the relative roles of CO2 increase, changing temperature and rainfall, and deforestation in the future, and the magnitude of their impact on atmospheric CO2 concentrations, we have applied a dynamic global vegetation model, using multiple scenarios of tropical deforestation (extrapolated from two estimates of current rates) and multiple scenarios of changing climate (derived from four independent offline general circulation model simulations). Results show that deforestation will probably produce large losses of carbon, despite the uncertainty about the deforestation rates. Some climate models produce additional large fluxes due to increased drought stress caused by rising temperature and decreasing rainfall. One climate model, however, produces an additional carbon sink. Taken together, our estimates of additional carbon emissions during the twenty-first century, for all climate and deforestation scenarios, range from 101 to 367 Gt C, resulting in CO2 concentration increases above background values between 29 and 129 p.p.m. An evaluation of the method indicates that better estimates of tropical carbon sources and sinks require improved assessments of current and future deforestation, and more consistent precipitation scenarios from climate models. Notwithstanding the uncertainties, continued tropical deforestation will most certainly play a very large role in the build-up of future greenhouse gas concentrations.

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Selected References

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  • Achard Frédéric, Eva Hugh D, Stibig Hans-Jürgen, Mayaux Philippe, Gallego Javier, Richards Timothy, Malingreau Jean-Paul. Determination of deforestation rates of the world's humid tropical forests. Science. 2002 Aug 9;297(5583):999–1002. [PubMed]
  • Cox PM, Betts RA, Jones CD, Spall SA, Totterdell IJ. Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model. Nature. 2000 Nov 9;408(6809):184–187. [PubMed]
  • Lucht Wolfgang, Prentice I Colin, Myneni Ranga B, Sitch Stephen, Friedlingstein Pierre, Cramer Wolfgang, Bousquet Philippe, Buermann Wolfgang, Smith Benjamin. Climatic control of the high-latitude vegetation greening trend and Pinatubo effect. Science. 2002 May 31;296(5573):1687–1689. [PubMed]
  • Malhi Y, Grace J. Tropical forests and atmospheric carbon dioxide. Trends Ecol Evol. 2000 Aug;15(8):332–337. [PubMed]
  • Phillips OL, Malhi Y, Higuchi N, Laurance WF, Nunez PV, Vasquez RM, Laurance SG, Ferreira LV, Stern M, Brown S, et al. Changes in the carbon balance of tropical forests: evidence from long-term plots . Science. 1998 Oct 16;282(5388):439–442. [PubMed]
  • Richey Jeffrey E, Melack John M, Aufdenkampe Anthony K, Ballester Victoria M, Hess Laura L. Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2. Nature. 2002 Apr 11;416(6881):617–620. [PubMed]

Articles from Philosophical Transactions of the Royal Society B: Biological Sciences are provided here courtesy of The Royal Society