Comprehensive drought assessment based on the SPEI and its impact on crop production and streamflow in Afghanistan

Afghanistan is a country with diverse climate zones. This study explored the diverse impacts of drought, with a focus on agricultural and hydrological aspects. A 40-year spatiotemporal analysis (1980–2020) using the standardized precipitation–evapotranspiration index (SPEI) formed the core of this research. The Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2) dataset, which contains long-term precipitation and temperature data, was selected for drought analysis. Severe droughts were observed in 2000, 2001, and 2018, whereas mild to moderate droughts occurred in 1984, 1985, 1989, 1990, 1995, 2004, and 2008. Drought severity was classified as mild (34.8 %), moderate (10.1 %), severe (4.4 %), or extreme (1.2 %). Varied temperature and rainfall patterns contributed to increased drought frequency and severity. Approximately 1 % of all the regions experienced extreme drought, with the Eastern Highlands having the highest percentage of severe (4.9 %) and moderate drought (11.3 %) and the Central Highlands having the highest percentage of mild drought (36.7 %). From 2014–2018, crop production for rice, wheat, barley, and maize declined significantly, particularly during the severe 2018 drought. Streamflow in rivers also decreased in 2014 and 2018, showing noticeable correlations with SPEI values. This study provides the first comprehensive analysis of drought impacts on crop production and streamflow across Afghanistan’s five climate zones, providing operational evidence to strengthen early warning, response planning, and climate resilience. • Insightful analysis of drought impacts on Afghanistan agriculture and surface water. • SPEI analysis reveals increasing drought frequency and severity across Afghanistan. • Severe 2018 drought led to significant declines in crop production and river streamflow. • Study reveals drought severity variations across Afghanistan’s five distinct climate zones. • Findings support drought-resilient farming, policy planning, and equitable water management.