From the crunchy corn chips on our tables to the delicate tofu in vegetarian dishes, the far-reaching impact of climate change is reshaping the global food landscape in profound and alarming ways. Recent research led by the University of British Columbia exposes a troubling new dimension of this crisis: climate change is not merely reducing the average yields of critical food crops but is significantly increasing year-to-year volatility, making food production more unpredictable and precarious than ever before.
This groundbreaking global study, published in Science Advances, analyzed decades of harvest data in conjunction with granular climate measurements. It focused explicitly on three cornerstone summer crops—corn, soybean, and sorghum—integral to food security and agricultural economies worldwide. The results reveal a stark reality: for every incremental degree Celsius of warming, the variability in annual crop yields escalates sharply, by as much as 19% in soybeans, 10% in sorghum, and 7% in corn. This volatility undermines the stability farmers depend on to plan and sustain their livelihoods.
While much prior research has concentrated on how global warming diminishes average yields, the novel insight of this study lies in highlighting instability itself as a mounting hazard. Food production is a gamble made on harvests that, for many farming communities, is already a high-stakes endeavor. The increasing unpredictability triggered by climate fluctuations means that bad years can hit harder and more frequently, and the buffer previously provided by average yields is dwindling rapidly.
“Farmers and the societies they feed don’t survive on averages—they survive on their actual harvest each year,” explains Dr. Jonathan Proctor, assistant professor at UBC’s faculty of land and food systems and the study’s lead author. Understood in the context of real human experience, a single disastrous growing season, marked by extreme heat or drought, can have cascading consequences—not only for farmers’ financial viability but for entire communities’ food security.
The study warns that as global temperatures rise, these yield swings will double, triple, or even quintuple in severity and frequency, steadily eroding the reliability of food systems. At just two degrees Celsius above the current climatic baseline, soybean crop failures that were once a centennial occurrence might become a quarter-century phenomenon. Similarly, corn and sorghum face a drastic contraction in the intervals between catastrophic harvest failures, increasing the frequency to mere decades. Looking forward to a scenario where emissions continue unabated, such failures for soybeans could occur as rapidly as every eight years by the close of the twenty-first century.
Alarmingly, the regions most vulnerable to these intensified fluctuations overlap significantly with some of the world’s most socioeconomically fragile places. Subsistence farmers in parts of Sub-Saharan Africa, Central America, and South Asia—areas where dependence on rainfall irrigation is prevalent and financial safeguards are thin or nonexistent—face a disproportionate risk. The absence of resilient infrastructure, irrigation systems, and crop insurance magnifies the consequences of a poor harvest, potentially escalating food scarcity and economic instability.
Nevertheless, this vulnerability is not confined to the developing world. Historical precedents demonstrate that developed agricultural regions are not immune to climatic shocks capable of destabilizing global food markets. For example, the devastating Midwest drought and heatwave in 2012 slashed corn and soybean yields by approximately 20%, triggering billions of dollars in losses and triggering a nearly 10% spike in global food prices within months. Such events underscore how interconnected and sensitive global food systems have become, making climatic volatility a crisis with worldwide ripples.
Central to the emerging pattern of increased instability is a compounding interplay between heat and moisture deficiencies. The researchers employed integrated datasets combining ground station records, satellite observations, and state-of-the-art climate models to parse how these factors converge. “The double whammy of heat and dryness arriving concurrently is a key driver of these dangerous yield fluctuations,” notes Dr. Proctor.
This coupling phenomenon exacerbates stress on crops in multiple physiological ways. Elevated temperatures accelerate evapotranspiration, rapidly depleting soil moisture and causing dry soils to heat more intensely. Crop plants experience disrupted pollination processes, shrinkage of vital growth periods, and heightened susceptibility to heat-induced cellular damage. Hence, even brief episodes combining high heat and drought conditions can cause disproportionate yield losses, especially in vulnerable soybean and sorghum cultivars.
The research also highlights irrigation’s critical role in mitigating these destabilizing effects when sufficient water resources are available. By maintaining soil moisture during heatwaves, irrigation dampens yield variability and bolsters resilience in the face of climatic extremes. However, many of the agricultural regions flagged as most at risk already grapple with acute water shortages or lack the infrastructure to implement large-scale irrigation, constraining this adaptive option.
With the looming threat of growing climatic volatility, the authors emphasize the urgent need for multifaceted responses to safeguard global food security. Priorities include accelerating breeding and adoption of heat- and drought-tolerant crop varieties, enhancing forecasting systems to anticipate extreme weather events, improving soil management practices that retain moisture and carbon, and expanding safety nets like crop insurance to protect vulnerable farming populations. Despite these adaptive strategies, mitigating greenhouse gas emissions remains paramount to limiting the escalation of instability and protecting the foundations of agriculture.
Dr. Proctor reminds us, “Not everyone cultivates the food, but everyone depends on it. As crop harvests become more erratic, the repercussions will reverberate far beyond the fields—impacting economies, prices, and ultimately, what ends up on our plates.” The challenge of a volatile food supply in the face of climate change is a complex and growing crisis that demands immediate, coordinated action from scientists, policymakers, and communities worldwide.
The study titled Climate change increases the interannual variance of summer crop yields globally through changes in temperature and water supply marks a critical advance in understanding how climate factors translate into risks not just for production quantity, but for reliability itself. By shining a light on the erratic fluctuations of essential staples, it galvanizes new urgency for an agricultural future that can withstand an unpredictable climate.
Subject of Research: Not applicable
Article Title: Climate change increases the interannual variance of summer crop yields globally through changes in temperature and water supply
News Publication Date: 3-Sep-2025
Web References:
https://www.science.org/doi/10.1126/sciadv.ady3575
References:
Proctor, J. et al. (2025). Climate change increases the interannual variance of summer crop yields globally through changes in temperature and water supply. Science Advances. DOI: 10.1126/sciadv.ady3575
Keywords:
Climate change effects, Food production
