IPCC AR5: Intergovernmental Panel on Climate Change Reports
Our research extensively features in Intergovernmental Panel on Climate Change Reports. Piers Forster was Coordinating Lead Author for the radiative forcing chapter in the IPCC fourth assessment report (link) and is currently lead author of the clouds and aerosol chapter in the IPCC's fifth assessment report, due out in 2014.
Forcing from AR4 climate models
Past and future simulations of climate change rely on accurate knowledge of climate change drivers. It is useful do evaluate changes in these forcing agents by the radiative/climate forcing, measured by a Wm-2 perturbation to the Earth's energy budget. However, this climate forcing is difficult to diagnose in today's very complex coupled ocean atmosphere climate models. In Forster and Taylor 2006(J. Clim. 19, pp.6181-6194. ) we develop and use a simple two step process to evaluate global-mean shortwave and longwave climate forcings, using standard diagnostics from climate model data submitted to the IPCC Model Data Center for the IPCC Fourth Assessment Report (AR4).
We use simple linear and energy balance arguments to firstly diagnose the model climate sensitivities, using 70 years of a 1%/year increase in CO2 experiment. We then use these, along with temperature change and flux diagnostics to find the climate forcing each model "sees". Please see the preprint for further details of our methodology, with Figures and Tables summarizing our results. In addition climate modellers may like time-series of the climate forcings from their model (as displayed in Figures 4, 5 and 6 of the paper): tables of these numerical forcing values can be downloaded below.
ASCII Text Table of Solar Forcings
ASCII Text Table of Shortwave Forcings (including solar forcing)
ASCII Text Table of Longwave Forcings
ASCII Text Table of Net Forcings
We acknowledge the international modeling groups for providing their data for analysis, the Program for Climate Model Diagnosis and Intercomparison (PCMDI) for collecting and archiving the model data, the JSC/CLIVAR Working Group on Coupled Modelling (WGCM) and their Coupled Model Intercomparison Project (CMIP) and Climate Simulation Panel for organizing the model data analysis activity, and the IPCC WG1 TSU for technical support. The IPCC Data Archive at Lawrence Livermore National Laboratory is supported by the Office of Science, U.S. Department of Energy.