Main areas of rice/maize/wheat production with the borders of the 10 top exporting countries highlighted. The donut charts indicate the shares of the three major crops in the global arable land area, calorie supply and agricultural commodity trade.
Illustration Credit: © Trnka et al., Earth's Future 14 (2026), e2025EF006095,
(CC BY 4.0)
Scientific Frontline: Extended "At a Glance" Summary: Climate-Driven Water Scarcity and Global Wheat Prices
The Core Concept: Simultaneous and severe water scarcity across multiple major agricultural regions significantly drives up the global market price of wheat. This price fluctuation is highly sensitive to the geographic extent of drought during critical crop growth phases, rather than just gradual climate-induced yield declines.
Key Distinction/Mechanism: The research utilizes a newly developed Severe Water Scarcity (SWS) indicator, which combines short- and long-term water deficits focusing specifically on the four months prior to harvest. This model explains 74 percent of the year-to-year variation in global wheat prices, distinguishing itself from traditional models that primarily assess gradual average yield changes.
Major Frameworks/Components:
- Severe Water Scarcity (SWS) Indicator: A globally applicable, crop-specific metric measuring moisture deficits immediately preceding the harvest season.
- Multi-Model Climate Simulations: The aggregation of 31 distinct global climate models to project future drought scenarios and their corresponding economic impacts on agricultural commodities.
- Warming-Price Projections: Statistical modeling indicating that 2 degrees Celsius of global warming relative to the 1951–1980 baseline projects average wheat prices at USD 273 per ton, escalating to USD 364 per ton at 3 degrees Celsius.
Branch of Science: Climatology, Agronomy, Crop Modeling, and Agricultural Economics.
Future Application: These findings will allow governments and international organizations to improve food security assessments by anticipating global market shocks caused by large, geographically connected, and recurrent water-scarcity events.
Why It Matters: Because wheat is a primary global staple food, climate-driven spikes in its price threaten international food security, affecting populations and household economies thousands of miles away from the drought-impacted fields.
A drought in one agricultural region can damage a harvest. But what happens when a 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’s Vulnerability 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 shortages. They then mapped these events across the areas where wheat, maize, and rice are grown and compared the affected areas with global commodity prices. The clearest signal emerged for wheat.
Water Scarcity Accounts for Most 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 will affect wheat prices. The direction is clear: as warming increases, severe water scarcity becomes more widespread, and estimated wheat prices rise. At 2°C warming relative to the 1951–1980 average, their model estimates an average wheat price of approximately $273 per ton. At 3°C, the estimate reaches $364 per ton, which is about three times 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 so far been difficult to capture and quantify. The results indicate that large-scale water scarcity across major production regions can indeed 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.
Published in journal: Earth's Future
Title: Climate-Induced Severe Water Scarcity Events as Harbingers of Global Wheat Price
Authors: Miroslav Trnka, Jan Meitner, Jan Balek, Song Feng, Juliana Arbelaez Gaviria, Milan Fischer, Esther Boere, Petr Havlík, Kurt-Christian Kersebaum, Claas Nendel, Margarita Ruiz-Ramos, Daniela Semerádová, Mikhail A. Semenov, Markéta Poděbradská, Jan Esper, Ulf Büntgen, Max Torbenson, Jáchym Brzezina, Zdeněk Žalud, Gabriel Katul, and Jørgen E. Olesen
Source/Credit: Johannes Gutenberg-Universität Mainz
Edited by: Scientific Frontline
Reference Number: as082426_01