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Assessing the robust impacts of land use change on the climate of the past 150 years and on the projected climate of the 21st century.

Abstract : Land-use change (LUC) is an important climate forcing due to the underlying alterations of the properties of the soil-vegetation system. However, the knowledge of these biogeophysical impacts of LUC is middling, notably due to the large number of processes involved. By means of model intercomparison and other approaches specifically developed, this study aims to identify the robust climate signals of LUC as well as to assess the associated uncertainties. LUC since the preindustrial period has led to extensive deforestation in the northern temperate regions and therefore to increases in surface albedo. The amplitude of this impact and the role of the non-radiative effects in summer are still quite uncertain within the model results. These uncertainties respond (1) to the way LUC is implemented in land surface models (LSMs) and (2) to the intrinsic model sensitivities to LUC. We show that the second point could explain more than 50% of the inter-model dispersion in key variables for the surface climate such as the evapotranspiration. We therefore developed statistical tools to reconstruct the impacts of LUC on the surface albedo and the evapotranspiration using present-day observations and the land-cover maps prescribed in the LSMs here assessed. The analyses carried out here show that current uncertainties in the climate impacts of LUC are in major part the result of the land-surface parameterizations used in climate models and, hence, could be reduced with a more thoroughly evaluation of LSMs.
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https://pastel.archives-ouvertes.fr/pastel-00787972
Contributor : Juan Pablo Boisier <>
Submitted on : Wednesday, February 13, 2013 - 2:29:52 PM
Last modification on : Friday, January 10, 2020 - 3:42:16 PM
Document(s) archivé(s) le : Saturday, April 1, 2017 - 11:40:23 PM

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  • HAL Id : pastel-00787972, version 1

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Juan Pablo Boisier. Assessing the robust impacts of land use change on the climate of the past 150 years and on the projected climate of the 21st century.. Earth Sciences. Ecole Polytechnique X, 2012. English. ⟨pastel-00787972⟩

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