Abstract ID: 179

Impacts of deforestation and climate change on Amazon tropical forests: Revision of a basin-wide assessment

Forests in Amazonia face a variety of threats ranging from the immediate to more long-term pressures. At present, human land-use and its impacts on deforestation through agricultural expansion and the introduction of fire, is the major cause of forest loss. However, over longer timeframes, the Amazon Basin has been identified as a potential &lsquotipping element’ where anthropogenic climate change may drive a rapid shift from tropical forest ecosystems to savannah-shrublands. Here we first present a revised version of LPJmL Dynamic Global Vegetation Model, tested using observational data for tropical forests including LBA sites. We then use it for to challenge our own earlier impact assessment (Cramer et al. 2004) focusing on the relative projected medium-term impacts of climate change and land use on tropical forest biogeography and biogeochemistry. We use climate projections from the IPCC Fourth Assessment Report (AR4) and deforestation projections from SimAmazonia to estimate carbon fluxes from land ecosystems to the atmosphere and the tropical Atlantic. Results are discussed from a policy perspective, where the implementation of REDD (Reduced Emissions and Deforestation and Degradation) via the Kyoto Protocol makes various assumptions of the response of forest systems to climate change following avoided deforestation. Using our modelling approach we are able to disentangle the relative role of climate and land-use change on tropical forest structure and assess both ecological and policy implications of the various threats facing tropical ecosystems.

Session:  Carbon - The LBA Model-Intercomparison Project.

Presentation Type:  Poster