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Climatic Change Consequences on Biome Distributions in South America: Simulations With Two Versions of the CPTEC Potential Vegetation Model (CPTEC-PVM)

Luis Fernando Salazar, Instituto Nacional de Pesquisas Espaciais, salazar@cptec.inpe.br (Presenting)
David Montenegro Lapola, Instituto Nacional de Pesquisas Espaciais, dmlapola@yahoo.com.br
Carlos Afonso Nobre, Instituto Nacional de Pesquisas Espaciais, carlos.nobre@inpe.br
Marcos Daisuke Oyama, Instituto de Aeronáutica e Espaço, oyama@iae.cta.br

We studied the consequences of projected climate change on biome distribution in South America in the 21st century by forcing two versions of the CPTEC potential vegetation model (CPTEC-PVM and CPTEC-PVM2 that include Carbon cycle) with climate scenarios from 15 climate models for two emission scenarios (A2 and B1). For current climate conditions, the two versions of the model successfully simulate the natural geographic distribution of biomes. Among the scenarios of climate change, the consensus of the results for each model version, show different patterns, due to the effect of the Carbon cycle feedback. The larger impacts of the climate change in biome distributions are concentrated in Amazonia and Northeast Brazil. The experiment with the model that not considers carbon cycle (CPTEC-PVM) indicates reduction of tropical forest cover areas which would be replaced by savannas. This reduction of tropical forest increase with the time through the 21st century, mostly over Southearn Amazonia. The CPTEC-PVM2 shows that in Southeastern Amazonia not exists consensus between the models about the future condition of the tropical forest. This result shows the effect of CO2 fertilization in support tropical forest in areas where temperature increase, so the decreasing of precipitation need to be greater to replace tropical forest by savanna. In this experiment the Net Primary Production (NPP) increase up to 100%. When limiting the NPP up to 25%, the areas with not consensus of the future condition of the tropical forest increase in relation with the experiment without limitations in the NPP. The insertion of the CO2-vegetation interaction mechanism (carbon cycle) results in prognostic different, less catastrophic, than those pointed by the CPTEC-PVM. The above results show that the response of the tropical forest to elevated CO2 is a critical question, and need to be more studied.

Science Theme:  LC (Land Use and Land Cover Change)

Presentation Type:  Poster

Abstract ID: 59

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