Abstract:
This dataset contains reconstructions of land use and land cover from AD 800 to 1992 in global coverage at 30 minute resolution. After AD 1700, the data is based on Ramankutty and Foley (1999), Foley et al. (2003) and Klein Goldewijk (2001); for earlier times, land use is estimated with a country-based method that uses national population data (McEvedy and Jones, 1978) as a proxy for agricultural activity. For each year, a map is provided that contains 14 fields. Each field holds the fraction the respective vegetation type covers in the total grid cell (0-1). The vegetation types comprise three human land use types (crop, C3 pasture and C4 pasture) and 11 natural vegetation types (based on the potential vegetation map of Ramankutty and Foley, 1999). For the time period prior to AD 1700 two additional land cover scenarios are provided (scenmin and scenmax). They quantify the uncertainties associated with this approach, through technological progress in agriculture and uncertainties in population estimates.
The additional datasets combine the known uncertainties in a way to give the most extreme range for possible estimates of land use area for each year before 1700. The datasets thus do not represent consistent time series of plausible alternative scenarios, but indicate, for each year, a maximum range outside which estimates of land use area are unrealistic. See citations and references for details.
Vegetation types:
1 Tropical evergreen forest
2 Tropical deciduous forest
3 Temperate evergreen broadleaf forest
4 Temperate/boreal deciduous broadleaf forest
5 Temperate/boreal evergreen conifers
6 Temperate/boreal deciduous conifers
7 Raingreen shrubs
8 Summergreen shrubs
9 C3 natural grasses
10 C4 natural grasses
11 Tundra
12 Crop
13 C3 pasture
14 C4 pasture