The IPCC’s Data Distribution Centre (DDC) provides the following information:
Observed climatic data for the period 1961-1990 for nine variables. These are global datasets, although the DDC also provides links to other global and national sources of observed climatic data. (The DDC guidance notes that while adequate monthly data can be frequently obtained from global or regional datasets, station data at higher resolution is usually obtained from national sources.)
Socioeconomic data and scenarios. These are collated from various sources such as World Bank, UNEP, and FAO, and include summary data on population, economic conditions, land cover/land use, water, agriculture/food, energy, biodiversity.
Data and scenarios for other environmental changes. These include data on global mean CO2 concentration, global and regional sea-level rise, regional ground-level ozone concentration, sulfate aerosol concentration and sulfur deposition. The scenarios were developed for the IPCC Third Assessment Report.
The DDC also provides guidelines for the use of the various data.