Climate change projections using the IPSL-CM5 Earth System Model: from CMIP3 to CMIP5

Jean-Louis Dufresne , Marie-Alice Foujols , Sébastien Denvil , Arnaud Caubel , Olivier Marti , Olivier Aumont , Yves Balkanski , Slimane Bekki , Hugo Bellenger , Rachid Benshila , Sandrine Bony , Laurent Bopp , Pascale Braconnot , Patrick Brockmann , Patricia Cadule , Frédérique Cheruy , Francis Codron , Anne Cozic , David Cugnet , Nathalie de Noblet , Jean-Philippe Duvel , Christian Éthé , Laurent Fairhead , Thierry Fichefet , Simona Flavoni , Pierre Friedlingstein , Jean-Yves Grandpeix , Lionel Guez , Éric Guilyardi , Didier Hauglustaine , Frédéric Hourdin , Abderrahmane Idelkadi , Josefine Ghattas , Sylvie Joussaume , Masa Kageyama , Gerhard Krinner , Sonia Labetoulle , Alain Lahellec , Marie-Pierre Lefebvre , Franck Lefèvre , Claire Lévy , Z.X. Li , James Lloyd , François Lott , Gurvan Madec , Martial Mancip , Marion Marchand , Sébastien Masson , Yann Meurdesoif , Juliette Mignot , Ionela Musat , S. Parouty , Jan Polcher , Catherine Rio , M. Schulz , Didier Swingedouw , Sophie Laval-Szopa , Claude Talandier , Pascal Terray , Nicolas Viovy , Nicolas Vuichard

We present the global general circulation model IPSL-CM5 developed to study the long-term response of the climate system to natural and anthropogenic forcings as part of the 5th Phase of the Coupled Model Intercomparison Project (CMIP5). This model includes an interactive carbon cycle, a representation of tropospheric and stratospheric chemistry, and a comprehensive representation of aerosols. As it represents the principal dynamical, physical, and bio-geochemical processes relevant to the climate system, it may be referred to as an Earth System Model. However, the IPSL-CM5 model may be used in a multitude of configurations associated with different boundary conditions and with a range of complexities in terms of processes and interactions. This paper presents an overview of the different model components and explains how they were coupled and used to simulate historical climate changes over the past 150 years and different scenarios of future climate change. A single version of the IPSL-CM5 model (IPSL-CM5A-LR) was used to provide climate projections associated with different socio-economic scenarios, including the different Representative Concentration Pathways considered by CMIP5 and several scenarios from the Special Report on Emission Scenarios considered by CMIP3. Results suggest that the magnitude of global warming projections primarily depends on the socio-economic scenario considered, that there is potential for an aggressive mitigation policy to limit global warming to about two degrees, and that the behavior of some components of the climate system such as the Arctic sea ice and the Atlantic Meridional Overturning Circulation may change drastically by the end of the twenty-first century in the case of a no climate policy scenario. Although the magnitude of regional temperature and precipitation changes depends fairly linearly on the magnitude of the projected global warming (and thus on the scenario considered), the geographical pattern of these changes is strikingly similar for the different scenarios. The representation of atmospheric physical processes in the model is shown to strongly influence the simulated climate variability and both the magnitude and pattern of the projected climate changes.

Mots clés: Carbon cycle; Greenhouse gases; CMIP3; Climate; Climate change; Earth System Model; Aerosols; Allowable emissions; Land use changes; CMIP5; Climate projections; RCP scenarios

Domaines: Climatologie

Jean-Louis Dufresne, Marie-Alice Foujols, Sébastien Denvil, Arnaud Caubel, Olivier Marti, et al.. Climate change projections using the IPSL-CM5 Earth System Model: from CMIP3 to CMIP5. Climate Dynamics, 2013, 40 (9-10), pp.2123-2165. ⟨10.1007/s00382-012-1636-1⟩. ⟨hal-00794170⟩