How Climate Change Is Transforming the Global Food Supply

Just months before Colorado’s winter wheat harvest, the crop experienced a dramatic temperature swing. Following a warm, dry winter, a cold snap exposed plants to freezing conditions for 12 hours. Two days later, temperatures climbed to almost 90 degrees Fahrenheit (32.2 degrees Celsius). By July, 73% of the crop was rated in poor or very poor condition. Early estimates from Colorado Wheat indicated that the state’s 2026 winter wheat harvest could be its smallest since 1965.

Colorado’s wheat crop is only one example of a much larger problem. Extreme weather and climate change are disrupting food production around the world. Rising temperatures can reduce crop yields, lower the nutritional value of staple foods and increase the risk of sudden agricultural crises.

The consequences will be especially severe in lower-income regions, where communities often cannot afford imported food. Climate-related famine, food shortages and nutritional deficiencies are already affecting vulnerable populations, and these risks are expected to grow as global temperatures rise.

The United States is not immune to these changes. Although farmers have overcome major agricultural challenges in the past, experts warn that adapting to a warmer, more unpredictable climate will require significant investment and innovation.

“There are real food security and nutrition concerns,” said Andrew Hultgren, an environmental economist at the University of Illinois Urbana-Champaign, “especially under these high-warming futures.”

Climate change is making some foods less nutritious

One of the less visible effects of climate change is a decline in the nutritional quality of crops. Plants grown in higher concentrations of atmospheric carbon dioxide can contain less zinc, protein, magnesium, iron and other essential micronutrients.

Crops are already less nutrient-dense than they were in the 1950s in some cases. Breeding programs that prioritize larger harvests over nutritional value have contributed to that decline. Higher carbon dioxide levels could intensify the problem.

The global monthly average concentration of carbon dioxide has now surpassed 420 parts per million, compared with a preindustrial average of approximately 280 parts per million. Unless emissions fall rapidly, concentrations are expected to rise further during this century.

A 2018 study estimated that by 2050, higher carbon dioxide levels could leave an additional 175 million people vulnerable to zinc deficiency and 122 million more people vulnerable to protein deficiency. Zinc deficiency can weaken immune function and impair childhood growth. Protein deficiency may contribute to stunted growth, fatigue, muscle weakness and stress fractures.

These estimates account primarily for carbon dioxide. Other climate-related changes, including drought, floods, heat waves and storms, could further reduce the calories and nutrients available to the global population.

Rising sea levels could flood farmland and increase soil salinity in coastal regions where rice and other crops are grown. Saltier soil can eventually make agriculture impossible. Meanwhile, drought, extreme heat, severe storms and sudden temperature changes can destroy harvests, causing food shortages and sharp price increases.

For consumers in the United States, the effects may appear as temporarily empty shelves, higher grocery bills or purchase limits, similar to the disruptions caused by recent bird flu outbreaks and egg shortages.

Extreme weather threatens crops, fisheries and food safety

Climate-driven changes that harm pollinators and increase the spread of plant diseases could also reduce agricultural yields. Harmful fungi and other pathogens may expand into new regions as temperatures and rainfall patterns change.

Ocean ecosystems face their own threats. Ocean acidification, warming seas and the decline of coral reefs are disrupting marine food chains. Coral reefs are important food sources for many coastal communities and provide habitat for fish that support local fisheries.

“Increasing sea temperature and increasing sedimentation within seas could lead to harmful algal blooms or increasing food poisoning events from temperature-related food spoilage,” said Christopher Golden, a professor of nutrition and public health at Harvard University.

Harmful algal blooms can contaminate shellfish, including oysters and scallops, with neurotoxins that may cause serious illness or death. Warmer conditions also accelerate food spoilage, especially in regions where seafood is landed and prepared outdoors without reliable refrigeration.

Fish are also moving toward cooler waters. As ocean temperatures rise, species may shift toward the poles, leaving vulnerable regions such as Southeast Asia, the Caribbean, Africa, Central America and the Pacific with fewer fish nearby.

Without effective climate mitigation, some small Pacific islands could experience fish catch declines of 58% to 92%, while Southeast Asia could face losses of 70% to 86%, according to research. Such declines would increase food insecurity and malnutrition. The United States could also be affected because much of its seafood is imported from tropical and subtropical waters.

Changes in global trade could soften some effects for American consumers, but they may also change what appears on grocery shelves. Higher prices and supply disruptions could encourage diets with more shelf-stable and highly processed foods, which are generally less beneficial for long-term health.

How climate change could change the foods we eat

Farmers and food producers are already adapting to climate change, sometimes in ways consumers may not immediately notice. As growing conditions shift, producers may choose different crops, move farms to new regions or select varieties that tolerate heat, drought and disease.

Apple growers in the Pacific Northwest and the northeastern United States, for example, may struggle with fewer cold days and more periods of extreme heat. Apple trees require specific winter conditions to become dormant and bloom properly. Reduced yields could eventually lead to higher prices, and establishing productive orchards in new regions can take five years or more.

Coffee production is also at risk. Arabica coffee, known for its smooth flavor, may become more expensive as warming temperatures and drought push growers out of traditional growing areas. Robusta coffee is more heat-tolerant, but it may also be threatened by increasingly unpredictable seasonal weather.

Wine is changing as well. Warmer growing conditions have already favored grapes that produce less-acidic, higher-alcohol wines. As temperatures continue to rise, the grape varieties suitable for vineyards in many regions may shift. Wildfires can create another problem by giving grapes and wine an unpleasant smoky or acrid flavor.

Heat stress is reducing milk production

Climate change is affecting animal agriculture, too. Many dairy cattle breeds used in the United States originated in the cool, cloudy climates of Northern Europe. As temperatures rise, heat stress reduces both milk production and the fat and protein content of milk.

Heat stress reduced annual milk yields by an average of 1% between 2012 and 2016, and climate-related losses could increase by 30% by 2050. The decline matters because demand for yogurt and cheese continues to rise, and both products depend heavily on milk’s fat and protein content.

“Fat and protein are what deliver the cultured dairy products that are in high demand,” said Jared Hutchins, an assistant professor of agricultural and consumer economics at the University of Illinois Urbana-Champaign.

Rising temperatures could reduce global calorie supplies

The effects of climate change add up across the agricultural system. Andrew Hultgren and his colleagues estimated that each degree of global warming could reduce crop-based calorie production by approximately 120 kilocalories per person per day—about 4.5% of the recommended daily intake.

That estimate, published in Nature in 2025, included adaptations farmers could make to limit crop losses. Without those adaptations, the reduction in available calories could be more than 30% larger.

In regions such as the Horn of Africa and India, fewer available calories could contribute to food shortages and malnutrition, said Marina Romanello, executive director of a climate-and-health research project at University College London. In wealthier countries, the effect may be felt primarily through food inflation and higher grocery prices.

Climate tipping points could create worst-case food scenarios

For farmers, climate change creates uncertainty in both the short and long term. Each growing season brings questions about drought, flooding, heat waves and severe storms. Producers must also decide whether to invest in new crop varieties, irrigation systems or unfamiliar farming methods.

Long-term climate tipping points present an even greater challenge. One major concern is the possible weakening or collapse of the Atlantic Meridional Overturning Circulation, or AMOC.

The AMOC is a system of ocean currents that transports warm surface water north from the equator and sends colder water south. It helps regulate the climate of Northern Europe, North America and the Southern Hemisphere.

If the AMOC collapsed, northwestern Europe could cool sharply. Some studies suggest that London could experience winter lows near minus 4 degrees Fahrenheit (minus 20 degrees Celsius), colder than the city’s current temperature records. Rainfall could decline across Europe, increasing drought risk.

The Amazon could also experience major changes, including a reversal of seasonal rainfall patterns, according to René van Westen, a climate researcher at Utrecht University.

However, if the AMOC does not collapse, London is expected to become warmer and wetter overall, with projected warming of approximately 4.9 degrees Fahrenheit (2.7 degrees Celsius) and seasonal precipitation increases of 15% to 18%. These contrasting possibilities make long-term agricultural planning difficult.

The timing and likelihood of an AMOC collapse remain uncertain, and any changes would unfold over decades or centuries. Even so, a major disruption would require a fundamental transformation of agriculture across Europe and the northeastern United States.

A global food-system collapse is not inevitable. Farmers are already responding to climate change by reducing water-intensive crops during drought years, improving irrigation and testing heat-resistant varieties. Better forecasting, crop diversity and investment in resilient food systems can also reduce risks.

Adaptation and emissions cuts can protect food security

Humanity has overcome serious agricultural threats before. During the 1950s and 1960s, improved rice and wheat varieties, combined with synthetic nitrogen fertilizers, helped drive the Green Revolution. These advances tripled global cereal yields while increasing farmland by only about 30%.

New technologies and farming strategies could similarly reduce hunger in a warmer world. Heat-tolerant crops, drought-resistant seeds, precision irrigation, improved soil management and more diverse food systems may help farmers maintain production.

However, adaptation alone cannot eliminate the risks. Research suggests that adapting to climate change could reduce crop calorie losses by approximately 30%, while cutting greenhouse gas emissions could reduce those losses by about half.

Reducing emissions could also limit the risk of severe changes to ocean circulation. Although the AMOC is already weakening, slowing global warming may help prevent further disruption and give ecosystems and agricultural systems more time to adapt.

“If you are cutting your emissions,” van Westen said, “you can lower your risk.”

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