Drylands are found worldwide covering 41% of all land and they are home to over 2 billion people: a third of humanity. They include a great variety of habitats including sub-humid forests, semi-arid savannahs, arid grasslands, desert oases, and many other beautiful and important ecosystems. Drylands support one third of the Global Conservation Hotspot Area and they are home to at least 28% of endangered species.
Drylands also provide important ecosystem services that benefit society. They provide fodder, food, fuel and other goods that are used to create resilient livelihoods. Despite their aridity, drylands include many major water sheds that supply water to billions of people while regulating hydrological cycles and mitigating flood and drought risks. Drylands also regulate climate locally, through provision of shade and shelter, and globally through capture and storage of carbon: more than a third of all terrestrial carbon is stored in drylands, mostly in dryland soils.
Challenges of the drylands
The drylands have uniquely high levels of climatic uncertainty and frequent periods of water shortage. Although they are labelled “low-potential areas” they include high-value resource zones, like oases and wetlands, which are vital to the survival of vast areas of land. They are shaped by natural forces including herbivore pressures and fire. Dryland biodiversity, cultures and livelihoods are highly adapted to these features. Misunderstanding of those adaptations, including the way people manage risks, continue to lead to harmful policies and investments.
Drylands are at risk of biodiversity loss and ecosystem degradation and this has consequences for human development and resilience. Drylands face particular threats from agriculture, expansion of settlements and infrastructure, and over-extraction of natural resources such as wood. 168 countries report to be affected by desertification, which is defined by the United Nations as land degradation in the drylands. Desertification is estimated to affect 30% of all drylands, contributing to loss of biodiversity, disruption of ecosystem functions, loss of resilience, and higher levels of poverty.