Land-cover and land-use information is important for both regional and sectoral assessment of climate change. Land-cover influences important ecosystem services, from the ability of ecosystems to sequester carbon, to regulating water flow and water quality, to providing products for human use, such as food crops and timber. There have been important changes in both land-cover and land-use over the past several decades in the U.S. Land-cover and land-use futures are determined in part by a wide variety of socioeconomic factors that are important in their own right. These include patterns of economic growth, changes in demand for agricultural and forest products, policies for land and habitat conservation, continued urban and suburban expansion, and climate variability and change being just a few.
Baseline Land Cover
For baseline data on land cover and use, the National Land Cover Database (NLCD) 2006 is a useful resource. The U.S. Geological Survey (USGS) has provided summaries of areas by land cover type within counties, states, and the National Climate Assessment (NCA) regions; the Agency is also finalizing a 10 km x 10 km aggregated version of the data.
The National Land Cover Database 2006, maintained by the Multi-Resolution Land Characteristics Consortium, provides a baseline land cover characterization for use by the NCA.
Population, Urbanization, and Land Use Projections
The U.S. Environmental Protection Agency, Global Change Research Program's Integrated Climate and Land Use Scenarios (ICLUS) project has developed downscaled socioeconomic and land use scenarios that are broadly consistent with the global-scale, peer-reviewed storylines of population growth and economic development of the Special Report on Emission Scenarios (SRES) scenarios used internationally. These scenarios have been rendered using a combination of models representing demography, migration, and spatial allocation of housing. The approach is documented in a peer-reviewed article that appeared in the Proceedings of the National Academy of Sciences (PNAS) - see the Additional Resources section of the ICLUS pages for access to the PNAS article and other documents. Data are available in a variety of formats and have been aggregated specifically for use by the NCA. An ICLUS Data for National Climate Assessment Web site provides access to the data — see the Downloads section of the ICLUS pages.