A Remotely Sensed Global Terrestrial Drought Severity Index

Water is essential for life. With increasing human development and climate change, water has become a pivotal resource for sustainable development, both societally and environmentally. Agriculture, on which a burgeoning population depends for food, is competing with industrial, household, and environmental uses for increasingly scarce freshwater supplies in many areas (Vörösmarty et al. 2010; Rosegrant et al. 2003). Drought is an important adverse climatic event for both ecosystems and human society. Global mean surface air temperature has increased by about 0.76°C since 1850 (Trenberth et al. 2007) and is expected to increase by 1.5°–6.4°C by the end of the twentyfirst century (Meehl et al. 2007). Under a warming climate, persistent drought may increase (Dai et al. 2004; Pachauri and Reisinger 2007; Dai 2011b), while human populations and associated demands for freshwater resources are rising, increasing food production constraints and putting global food security at risk. Accurate and consistent global mapping and monitoring of drought severity is essential for water management and drought mitigation efforts