Soils and Humans

Abstract

The new Global Land Cover Share database (Latham et al., 2014) includes eleven global land cover layers, each representing the major land cover classes defined by the FAO and SEEA legend (Weber, 2010). Analysis of the database indicates that of the global land mass, artificial surfaces occupy 0.6 percent, croplands 12.6 percent, grasslands 13.0 percent, tree-covered areas 27.7 percent, shrub-covered areas 9.5 percent, herbaceous vegetation 1.3 percent, mangroves 0.1 percent, sparse vegetation 7.7 percent, bare soils 15.2 percent, snow and glaciers 9.7 percent and inland water bodies 2.6 percent. The intensity of each land-cover type varies substantially across the globe according to numerous factors, including soils, altitude, climatic conditions and anthropogenic influences. For example, while cultivated land is less than 10 percent in most African regions, it accounts for more than 25 percent of the land in the Asia region. A land cover map is given in Figure 4.1. Summary statistics by region, derived from the respective GIS layers are given in Figure 4.2. In the following discussion, attention is focused on three main land cover classes: cropland, grasslands/grazing lands and forests. The management of these three classes has large impacts on soils and ecosystem services. The presence of artificial surfaces is treated in more detail in Section 6.7. More than 25 percent of the land mass carries almost no vegetation because of climatic factors (glaciers, deserts) or topographic or soil conditions.