Plant and soil characteristics as key predictors forfuture agricultural drought

Abstract Drought is one of the most complex and multidimensional types of extreme events, with meteorological and agricultural
droughts being two of the most widely studied types. Here, we analyze agricultural drought with a crop water stress index
that incorporates plant and soil characteristics and soil moisture. The new index is evaluated against other standardized
meteorological drought indices, such as the Standardized Precipitation Index and the Standardized Soil Moisture Index. The
results show substantial differences between the standardized indices and the crop water stress index. To study future drought
patterns, we use multiple future scenarios simulated by the Max Planck Institute Earth system model. In contrast to the
standardized indices, the results of the crop water stress index show an improvement in the future global mean drought
conditions due to a greater increase in mean wet than dry conditions governed by soil moisture and precipitation, while both
dry and wet extreme conditions increase in intensity. Nonetheless, the results suggest large cropland areas will be subject to
intense drought conditions under the Shared Socioeconomic Pathways SSP-1.19 to SSP-5.85. Such drought assessment can
only be supported by using more complex drought indices. Our results emphasize the importance of combining plant and soil
information with standardized indices in the assessment of drought-driven crop stress under climate change aiding effective
policy formulation.