Arid Lands

Environment and Population

Popular misconceptions conceive drylands as empty spaces that are barren and unproductive. In reality, drylands are complex ecosystems with unique biodiversity and environmental goods and services that provide a basis of living for millions of people. Drylands cover a range of ecosystems that are highly heterogeneous in their topography, climate, geology, and biodiversity. Drylands are comprised of deserts (except hyper-arid deserts), grasslands, savannas, shrublands and woodlands, agricultural lands, and urban areas. Plants and animals have to cope with scarce water supplies due to low annual rainfall, high variability, and high temperatures. Most species have adapted to the conditions, such as plants that have deep and extensive root systems and photosynthesize at night, and animals that stay inactive during the day. The lack of reliable rainfall makes other water sources, such as groundwater, streams, and dew, even more important.

Growing populations in arid lands exert pressure on local resources, extending cultivation into marginal areas.

Drylands are generally exposed to climate regimes that are not favorable for crop production, as rainfall patterns are unpredictable. Nonetheless, more than two billion people live in drylands, mainly in [Page 70]developing countries. Here, populations are among the poorest in the world. Particularly in Africa, South America, and Asia, inhabitants are heavily dependent on dryland resources to meet their basic needs. Drylands lag far behind in economy, infrastructure, well-being, and development terms. For instance, infant mortality in drylands in developing countries is twice as high as in nondryland areas, and 10 times higher than in developed countries. Moreover, access to clean drinking water and adequate sanitation is inadequate and leads to poor health conditions.

Although drylands are considered marginal for agriculture due to limited water resources, they currently account for more than 40 percent of the global cultivated area. Communities make a living as small-scale farmers or livestock herders and rely on drylands for wood fuel, construction materials, and medicinal plants. However, people are highly vulnerable to periodic droughts and are affected by food insecurity. While the majority of populations live in rural areas, large cities are located in drylands, such as Cairo, Mexico City, Teheran, Cape Town, and Las Vegas. Drylands have supported people's livelihoods for thousands of years. Their communities are highly resilient and have developed sustainable lifestyles and systems allowing them to survive in these harsh conditions and manage limited natural resources. Drylands are also the origin of important food grains (such as wheat, sorghum, barley, and millet).

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