Aridification, precipitations and crop productivity: evidence from the aridity index.

The article investigates the economic impact of climate change–induced aridification—defined as the combined effect of precipitation and potential evapotranspiration (PET)—on global agricultural productivity. Using a novel, high-resolution global dataset from 1995 to 2010 covering maize, rice, soybean, and wheat yields, the study finds that increased PET has led some regions to become arider despite rising precipitation, with significant negative effects on crop yields, especially in lower- and middle-income countries in Africa and Asia. Projections under an intermediate greenhouse gas emissions scenario (RCP 4.5) indicate that global arid areas will expand by 3.9% by 2040, potentially causing losses of approximately 20 million tons of maize, 19 million tons of rice, 8 million tons of soybeans, and 21 million tons of wheat if no mitigation actions are taken. The research highlights that aridity indices, which incorporate both precipitation and PET, better explain variations in crop yields than precipitation alone, emphasizing the importance of considering soil water availability in assessing climate change impacts on agriculture.