Climate Change Fact Sheet 103 Desertification and climate change Desertification is a widespread environmental problem that directly affects over 100 countries on all the inhabited continents. Drylands cover around one third of the world's land surface and are inhabited by more than one sixth of its population. For the millions of people whose livelihoods depend on the productivity of these marginal areas, desertification creates additional environmental stress. It also contributes to a variety of global environmental problems, including greenhouse gas-induced climate change, loss of biodiversity, and pollution of international waters. Global climate change may in turn accelerate desertification if higher temperatures increase evaporation or if rainfall decreases.
Human activity is the fundamental cause of desertification.
The natural fragility of dryland ecosystems renders them extremely vulnerable to inappropriate land use and over-exploitation. This is particularly true during periods of environmental stress such as seasonal dryness, drought, or high winds. Over-exploitation of the land can result from many different forms of social, economic, and political pressure. Farmers often over-cultivate the few available areas of fertile land to increase production of export crops. Unless such pressures are eased, dryland communities will become increasingly vulnerable to climate variations.