Project: IPCC Data Distribution Centre : Third Assessment Report data sets - The Intergovernmental Panel on Climate Change (IPCC) has been established by WMO und UNEP to assess scientific, technical and socio-economic information, relevant for the understanding of climate change, its potential impacts and option for adaption and migration. Projection of future trends for a number of key variables are provided through this section of the DDC (http://ipcc-data.org/sim/gcm_clim/SRES_TAR ). This information contained in either IS92 emission scenarios (IPCC 1992), the Special Report on Emission Scenarios (IPCC 2000, SRES) or published model studies using data from these scenarios. Six alternative IPCC scenarios (IS92a to f) were published in the 1992 Supplementary Report to the IPCC Assessment. These scenarios embodied a wide array of assumption affecting how future greenhouse gas emissions might evolve in the absence of climate policies beyond those already adoped. The SRES scenarios have been constructed to explore future developments in the global enviromental with special reference to the production of greenhouse gases and aerosol precursor emission. A set of four scenario families (A1, A2, B1, B2) have been developed that each of this storylines describes one possible demographic, polito-economic, societal and technological future. Model experiments, also using different forcing scenarios, were calculated at other modeling centres. Emissions Scenarios. 2000 ,Special Report of the Intergovernmental Panel on Climate Change Nebojsa Nakicenovic and Rob Swart (Eds.) Cambridge University Press, UK. pp 570 Summary: The SRES data sets were published by the IPCC in 2000 and classified into four different scenario families (A1, A2, B1, B2). SRES_A2 storyline describes a very heterogeneous world with the underlying theme of self-reliance and preservation of local identities. It results in this scenario a continous increasing population together with a slower economic growth and technological change. The atmospheric component AGCM2 is a spectral model with triangular truncation at wave no. 32 and 10 vertical levels. The ocean model component based on the GFDL MOM 1.1 code with 29 vertical levels and has a isopycnal / eddy stirring parameterization (Gent and McWilliams, 1990). CGCM2 (http://ec.gc.ca/ccmac-cccma/default.asp?lang=En&n=40D6024E-1 ). The changes of anthropogenic emissions of CO2, CH4, N2O and sulphur dioxide are prescribed according to the above mentioned scenario. These data belongs to a set of three ensemble runs, with the CCCma-model, using the SRES_A2 scenario. They provide monthly averaged values of selected variables for the IPCC-DDC.