Drought affects more people than any other type of natural disaster and is the most damaging to livelihoods, especially in developing countries. Recent trends indicate that droughts are increasing in magnitude and severity, affecting livelihoods and food security, and generating losses that may be felt well beyond drought-affected areas.

Monitoring crop growth across the globe is crucial to forecast production and provide early warning of situations where crop failures may lead to food shortages.

As ground meteorological data for drought monitoring is seldom adequate or timely, FAO developed the Agricultural Stress Index System (ASIS), together with the Flemish Institute for Technological Research (VITO) and the Joint Research Centre of the European Commission.