The duration and frequency of drought under a changing climate (Briefing 2.9)

Abstract

Drought is an extended period of time with rainfall deficits. It is a natural hazard having environmental-, social and economical impacts. An index can be used to define the onset of drought and to simplify the wide range of impacts. By applying such an index, the severity of a current drought event can be quantified and compared to past conditions. In combination with climate projections, future droughts can furthermore be addressed. A drought index also facilitates the communication between scientist, decision makers and the public. In the present study, a drought index was applied and the duration as well as the frequency of droughts during a future time period (2031-2060) was compared to a current reference period (1961-1990). To furthermore address the impact of droughts on the agricultural sector, the Irrigation Water Demand (IWD) during drought was simulated with the hydrological model TRAIN. Results show that future droughts are projected to become longer and more severe and that the irrigation water demand is expected to rise under future drought conditions.