5.1 Introduction: importance, scope and uncertainty, Third Assessment Report summary, and methods

5.1.1 Importance of agriculture, forestry and fisheries

At present, 40% of the Earth’s land surface is managed for cropland and pasture (Foley et al., 2005). Natural forests cover another 30% (3.9 billion ha) of the land surface with just 5% of the natural forest area (FAO, 2000) providing 35% of global roundwood. In developing countries, nearly 70% of people live in rural areas where agriculture is the largest supporter of livelihoods. Growth in agricultural incomes in developing countries fuels the demand for non-basic goods and services fundamental to human development. The United Nations Food and Agriculture Organization (FAO) estimates that the livelihoods of roughly 450 million of the world’s poorest people are entirely dependent on managed ecosystem services. Fish provide more than 2.6 billion people with at least 20% of their average per capita animal protein intake, but three-quarters of global fisheries are currently fully exploited, overexploited or depleted (FAO, 2004c).