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Title: Combined Climate and Carbon-Cycle Effects of Large-Scale Deforestation

Combined Climate and Carbon-Cycle Effects of Large-Scale Deforestation The prevention of deforestation and promotion of afforestation have often been cited as strategies to slow global warming. Deforestation releases CO{sub 2} to the atmosphere, which exerts a warming influence on Earth's climate. However, biophysical effects of deforestation, which include changes in land surface albedo, evapotranspiration, and cloud cover also affect climate. Here we present results from several large-scale deforestation experiments performed with a three-dimensional coupled global carbon-cycle and climate model. These are the first such simulations performed using a fully three-dimensional model representing physical and biogeochemical interactions among land, atmosphere, and ocean. We find that global-scale deforestation has a net cooling influence on Earth's climate, since the warming carbon-cycle effects of deforestation are overwhelmed by the net cooling associated with changes in albedo and evapotranspiration. Latitude-specific deforestation experiments indicate that afforestation projects in the tropics would be clearly beneficial in mitigating global-scale warming, but would be counterproductive if implemented at high latitudes and would offer only marginal benefits in temperate regions. While these results question the efficacy of mid- and high-latitude afforestation projects for climate mitigation, forests remain environmentally valuable resources for many reasons unrelated to climate.
Authors: ; ; ; ; ; ;
Publication Date:
OSTI Identifier:907848
Report Number(s):UCRL-JRNL-225431
TRN: US200721%%421
DOE Contract Number:W-7405-ENG-48
Resource Type:Journal Article
Data Type:
Resource Relation:Journal Name: Proceedings of the National Academy of Sciences, N/A, no. 16, April 17, 2007, pp. 6550-6555; Journal Volume: 16
Research Org:Lawrence Livermore National Laboratory (LLNL), Livermore, CA
Sponsoring Org:USDOE
Country of Publication:United States
Language:English
Subject: 09 BIOMASS FUELS; 54 ENVIRONMENTAL SCIENCES; ALBEDO; CARBON CYCLE; CLIMATE MODELS; CLIMATES; CLOUD COVER; DEFORESTATION; FORESTS; GREENHOUSE EFFECT; MITIGATION