A new international study has identified a powerful link between drought across the world’s wheat-growing regions and the price of wheat on global markets, warning that climate change could turn increasingly widespread water shortages into a major threat to food affordability. Using climate observations, crop maps, commodity-price records, and dozens of climate-model simulations, researchers found that the area of wheat-producing land affected by severe water scarcity closely tracks year-to-year changes in global wheat prices. Under approximately 3°C of global warming, the study estimates that average wheat prices could rise to about US$364 per ton—roughly three times the inflation-adjusted global wheat price recorded in 2010.
The research, published in Earth’s Future, examines a risk that conventional climate assessments may overlook. Earlier studies have often focused on gradual changes in average crop yields, asking how much less wheat might be harvested as temperatures rise. The new analysis instead investigates what happens when drought strikes several major agricultural regions at once, or when severe water shortages move from one production center to another over successive growing seasons. This distinction is critical because international food markets do not respond only to the average amount of wheat produced. They also react sharply to synchronized shocks that reduce confidence about future supplies.
Wheat was selected because it occupies an unusually important position in the global food system. It is cultivated across more land than rice or maize, supplies a substantial share of the world’s calories and protein, and is among the most heavily traded agricultural commodities. Wheat is also frequently grown in regions where water availability is already limited. Unlike rice, which is often produced with substantial irrigation, wheat production depends more heavily on rainfall and stored soil moisture. Approximately 15% of the global harvested wheat area is irrigated, compared with about 33% of rice-growing land, making wheat particularly exposed when rainfall fails during sensitive stages of development.
To measure this exposure, the researchers developed a crop-specific indicator called severe water scarcity, or SWS. The indicator combines short-term and long-term water deficits, capturing both recent rainfall shortages and the depletion of moisture accumulated in soil and other parts of the hydrological system. It focuses on the four months before harvest, a period when wheat crops are especially vulnerable to insufficient water. During this window, drought can restrict growth, reduce grain formation, and shrink the final harvest. By mapping SWS across the world’s wheat, maize, and rice-growing areas, the team could compare the geographic scale of water stress with changes in global commodity prices.
The relationship was strongest for wheat. A statistical model based solely on the extent of severe water scarcity explained 74% of the year-to-year variation in global wheat prices between 2000 and 2021. That result does not mean drought determines every movement in the market, but it indicates that the geographic reach of water stress contains a remarkably strong signal. The model was also tested against data from 2022 through 2024, even though those years were excluded during its development. It continued to reproduce broad wheat-price levels and changes during this out-of-sample period, which included unusually turbulent conditions in global food and energy markets.
The signal was weaker for maize and absent for rice. Severe water scarcity explained as much as 40% of maize-price variability, while the researchers found no meaningful relationship between the indicator and global rice prices. Differences in production systems may help explain the contrast. Rice is more commonly grown under irrigated conditions, and its cultivation is concentrated in regions with distinct water-management practices. Wheat, by comparison, is spread across a wider belt of often drier agricultural landscapes and is more directly exposed to rainfall failure. This makes simultaneous drought across wheat-growing regions more likely to produce a measurable effect in international markets.
Historical data show that the climate signal is already changing. Between 1911 and 2020, an average of approximately 5% of the world’s wheat-growing area was affected by severe water scarcity in any given year. Yet in 2000, 2010, 2012, and 2020, the affected area exceeded 15%. These peaks represent more than isolated local disasters. When drought covers a large share of the world’s production base, exporters may have less grain available, importing countries may compete more aggressively for supplies, and traders may bid up prices in anticipation of further losses. Even before a harvest is completed, expectations about scarcity can amplify price movements.
The researchers then used global climate-model simulations to explore how the drought-price relationship could evolve as warming continues. Their results show a clear progression: higher temperatures increase the likelihood and extent of severe water scarcity, which in turn is associated with higher estimated wheat prices. At approximately 2°C of warming relative to the 1951–1980 baseline, the model projects an average wheat price of about US$273 per ton. At approximately 3°C, the estimate rises to around US$364 per ton. The comparison with 2010 is inflation-adjusted, and the projected figure at 3°C is approximately three times the global wheat price of that year.
The study does not claim that drought alone controls the cost of bread, pasta, or other wheat-based foods. Energy prices, fertilizer costs, grain inventories, exchange rates, trade restrictions, market expectations, pests, plant diseases, and geopolitical conflicts can all alter agricultural markets. Russia’s invasion of Ukraine, for example, demonstrated how quickly disruptions in major exporting regions can affect global grain flows. Nevertheless, the researchers argue that large-scale water scarcity has been an underappreciated component of this system. When severe drought affects multiple production regions simultaneously or in rapid succession, international trade may not be sufficient to buffer the shock.
The implications reach far beyond farms. Wheat is a staple for billions of people, and higher global prices can place the greatest pressure on households that spend a large share of their income on food. Countries dependent on imports may face rising bills, while governments may respond with export controls, subsidies, or emergency purchases that further reshape the market. The findings suggest that food-security planning must account not only for slow changes in average yields but also for recurrent, geographically connected drought events. IIASA researcher and study coauthor Petr Havlík said the projected scale of water scarcity and its potential impact on commodity prices could require a profound transformation of the food system if it is to continue supplying affordable food in the coming decades. The research was led by Miroslav Trnka of the Global Change Research Institute of the Czech Academy of Sciences and involved scientists from institutions across Europe and the United States.
Subject of Research:
The connection between climate-induced severe water scarcity across global wheat-growing regions and international wheat prices.
Article Title:
Climate‐induced severe water scarcity events as harbingers of global wheat price
Web References:
https://doi.org/10.1029/2025EF006095
References:
Trnka, M., Meitner, J., Balek, J., Feng, S., Arbelaez Gaviria, J., Fischer, M., Boere, E., Havlík, P., et al. (2026). “Climate‐induced severe water scarcity events as harbingers of global wheat price.” Earth’s Future. DOI: 10.1029/2025EF006095
Keywords:
Climate change, drought, severe water scarcity, wheat prices, food security, global markets, agriculture, crop yields, water stress, climate models, wheat production, commodity prices, warming, international trade
