IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group I: The Physical Science Basis

Figure 2.15. Anthropogenic modifications of land cover up to 1990. Top panel: Reconstructions of potential natural vegetation (Haxeltine and Prentice, 1996). Lower panels: reconstructions of croplands and pasture for 1750 and 1990. Bottom left: fractional cover of croplands from Centre for Sustainability and the Global Environment (SAGE; Ramankutty and Foley, 1999) at 0.5° resolution. Bottom right: reconstructions from the HistorY Database of the Environment (HYDE; Klein Goldewijk, 2001), with one land cover classification per 0.5° grid box.