Deserts and semiarid areas are in 'drylands', which comprise hyper- arid, arid, semiarid and dry sub-humid areas . Drylands cover about 45-47% of the global land area  and are home to about 3 billion people residing primarily in semiarid and dry sub-humid areas . Drylands host unique, rich biodiversity  and provide important ecosystem services , while dryland people have a rich cultural and historical heritage. Rural human populations are growing in some Mediterranean and tropical drylands, while many are rapidly urbanising , with varying impacts on ecosystem services and adaptive capacities. In recent decades, 6% of global megacities have been established in arid areas and 2% in hyper-arid desert areas , with many of these areas suffering from severe water security challenges . Dryland inhabitants in many developing countries are also experiencing poverty , hunger, poor health, land degradation, and economic and political marginalisation , which sometimes limits their access to common pool resources. These challenges, together with a weak enabling environment, threaten opportunities to adapt to climate change.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report