Spatiotemporal analysis of aridity index and its relationship with crop productivity trends

Abstract

While global crop production has risen 40% since 1990, aridity-driven losses have offset an estimated one-fifth of those gains in dryland regions. This research analysed the UNEP aridity index (P/PET) across the North China Plain (1990-2020) and its relationship with wheat, maize, and rice yield anomalies using CRU TS 4.06 climate data at 0.5° resolution. Arid plus hyper-arid area expanded from 23.6% to 28.9%. Yield anomaly correlated quadratically with AI (R² = 0.78-0.84), peaking at AI = 0.65-0.70. Counties with AI decline > 0.05 per decade showed 12-18% lower yield trends. These results quantify the productivity cost of aridification in a major global breadbasket.