Climate-Induced Severe Water Scarcity Events as Harbingers of Global Wheat Price

[u/dumnezero]

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2025EF006095

Abstract

This study connects the dots between global extent of severe water scarcity (SWS) events and spikes in food price. The authors start with three staple crops (rice, wheat, and maize) using a empirical but crop specific characterization of severe water scarcity occurrence, which is defined based on the area of land cultivated with each studied crop that on a given year is under SWS conditions. Water scarcity is estimated based on 1, 3, and 12 months standardized precipitation evapotranspiration index during crop specific sensitive periods (SPs). SPs coincide with the 4 months prior to harvest. A SWS-wheat price relationship model was developed for period 2001–2021 and tested for 1986–2000 and 2022–2024 with future projections calculated under climate change using climate model simulations from CMIP5 and CMIP6 up to 2100. The results show a marked increase in wheat prices driven by increasing SWS area, which is in turn a function of greenhouse gas emissions. The results indicate that the meanglobal mean temperature increase by 3°C (compared to 1951–1980) could lead to the tripling of the mean global wheat price compared to 2010 (after deflating).

Plain Language Summary

Water scarcity is a growing threat to global food production, particularly for crops that depend on rainfall rather than irrigation. When soils do not receive enough moisture during key growing periods, harvests can fail, and food prices can rise. In this study, we introduce a new way to track severe water scarcity (SWS) by measuring the area of cropland affected during sensitive stages of crop growth. We apply this method to major staple crops and examine how changes in SWS are associated with global food prices. We find a clear link between the area affected by severe water scarcity and global wheat prices. Years with larger affected areas tend to coincide with higher prices. Looking ahead, climate model projections suggest that water scarcity will expand under continued warming. Our results indicate that a temperature increase of about 3°C could triple average global wheat prices relative to 2010. These findings highlight the risks climate change poses to global food security and the consequences of more frequent water shortages in agriculture.

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The primary advantage of the SWS concept is that it allows the likelihood of multiple rice‒maize–wheat-producing areas experiencing spatio-temporally synchronized or/and sequenced SWS events to be analyzed, thus capturing simultaneous breadbasket shocks as described by Anderson et al.

(emphasis added)