Climate-driven water scarcity increases wheat prices globally
Interdisciplinary study connects drought across the world’s wheat-growing regions with global markets
A drought in one agricultural region can damage harvest. But what happens when severe water shortage affects several of the world's major wheat-producing regions at the same time — or one follows another over successive years? An international team of scientists has brought together climate observations, crop geography, global commodity prices, and dozens of climate-model simulations to address this question. Their study reveals a strong connection between the extent of severe water scarcity across wheat-growing regions and the global price of wheat — a link that could become increasingly important as the planet warms. The study, led by Professor Miroslav Trnka of the Global Change Research Institute (CzechGlobe) at the Czech Academy of Sciences, with contributions by Professor Jan Esper of the Institute of Geography at Johannes Gutenberg University Mainz (JGU) and Professor Max Torbenson, who has since moved from JGU to Texas A&M University in the United States, was recently published in Earth's Future.
Wheat being particularly vulnerable to widespread water shortages
The researchers focused on wheat because of its exceptional importance to the global food system. Wheat is grown across more land than either rice or maize, is a major source of calories and protein, and is one of the most internationally traded agricultural commodities. Much of it is also grown under relatively water-limited conditions. Until now, assessments of climate- change impacts on food prices have often concentrated on gradual changes in average crop yields. The new study, however, addressed a different question: Can the extent of drought during crop growth explain global cereal prices?
Answering that question required researchers across climate science, agronomy, crop modeling, and global food-system analysis to connect several pieces of the puzzle. The team first developed a globally applicable but crop-specific indicator called Severe Water Scarcity (SWS). It combines short- and long-term water deficits and focuses on the four months before harvest, when crops are particularly sensitive to water shortage. They then mapped these events across the areas where wheat, maize, and rice are grown and compared affected areas with global commodity prices. The clearest signal emerged for wheat.
Water scarcity accounts for most of the fluctuations in wheat prices
Their model based only on severe water scarcity explained 74 percent of the year-to-year variation in global wheat prices between 2000 and 2021. Interestingly, the model was developed without using data from 2022–2024, yet it still captured the broad wheat-price levels and changes during these years, providing an out-of-sample test under exceptionally turbulent market conditions. For maize, severe water scarcity explained up to 40 percent of price variability, while no meaningful relationship was found for rice.
Rising wheat prices due to increasing global warming
The researchers used simulations of 31 global climate models to explore how future droughts affect wheat prices. The direction is clear: as warming increases, severe water scarcity becomes more widespread and estimated wheat prices rise. At 2 degrees Celsius warming relative to 1951 to 1980, their model estimates an average wheat price of approximately USD 273 per ton. At 3 degrees Celsius, the estimate reaches USD 364 per ton, which is about three times as much as the inflation-adjusted global wheat price in 2010.
Climate-related signal for global agricultural markets
The study does not suggest that drought alone determines wheat prices. It acknowledges that energy and fertilizer costs, grain stocks, exchange rates, trade policies, market expectations, pests and diseases, and geopolitical conflicts all influence food markets. However, the research identifies a climate-related signal that has been so far difficult to capture and quantify. And the results indicate that indeed large-scale water scarcity across major production regions can propagate through the global wheat market.
This matters because wheat is not simply another commodity. It is a staple food for a large part of the world's population. When severe drought spreads across several major production regions, the consequences can travel far beyond the affected fields — through international markets to countries and households thousands of miles away. The findings therefore suggest that future assessments of food security should look beyond gradual changes in average yields. They also need to consider large, recurrent, and geographically connected water-scarcity events affecting several important production regions simultaneously or in close succession.
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