Impacts of integrated meteorological and agricultural drought on global maize yields

In agricultural production, drought-related losses significantly impact global food security. Composite drought indices provide superior monitoring of drought conditions compared to single indices; however, research on their effectiveness for monitoring drought in global maize-growing regions remains limited. In this study, we investigated the spatial and temporal variations in drought and its impacts on maize production using the composite agricultural drought index (CADI), which integrates the standardized precipitation evapotranspiration index (SPEI) and the standardized soil moisture index (SSMI) based on the Copula function. The impacts of drought on the meteorological maize yield were quantified across global maize-growing regions from 1981 to 2022. CADI effectively determined the combined effects of meteorological and agricultural drought, demonstrating greater validity and reliability than SPEI or SSMI. From 1981–2022, drought conditions intensified in 72 % of global maize-growing regions, with significant intensification in more than 30 % of these regions. CADI was positively correlated with the meteorological maize yield in approximately 71 % of regions, with significant correlations in 18 % of regions. Positive correlations were also found in 73 % of countries based on national-scale analysis, with significant correlations in 20 % of countries, highlighting the critical impact of drought on yield. Increasing drought sensitivity was observed in 57 % (50 %) of global maize growing regions (countries), indicating the rising impact of drought on yield in these regions. The results suggest that increasing drought under warming may intensify the risk of maize yield decline, providing a scientific foundation for global adaptation strategies to mitigate the adverse effects of environmental stress on agricultural production.