Extreme Heat is Reshaping What You Eat

Vibrant fruits and vegetables supply market. Credit: Photo by Uwe Scharrer, Pexels

1.23 billion people depend on agriculture for their livelihoods.  

Extreme heat is now one of the greatest threats to that system – quietly reshaping what ends up on our plates and how secure our food future really is.  

What may feel like just another hot summer is a growing crisis unfolding in real time – affecting not just farmers, but food systems that everyone relies on. This is based on a new report by the United Nations Office for Disaster Risk Reduction, the Food and Agriculture Organization, and World Meteorological Organization. 

Complementing this, a recent study published in Nature Food reveals deep structural imbalances in global food systems, with many countries unable to meet nutritional needs through domestic production alone, raising urgent questions about resilience and who bears the greatest risk in a warming world. 

Key Developments 

• Extreme heat is identified as one of the most acute hazards facing global agriculture, which threatens the livelihoods of 1.23 billion people. 

• A single extreme heat event can trigger cascading impacts across interconnected systems (crops, livestock, fisheries, forests)  

• Heat stress directly affects crop yields, pasture quality, freshwater ecosystems, and wildfire risk  

• For every 1°C of additional warming, we expect a projected 4-10% decline in yields of staple crops such as maize and wheat. 

• Agriculture workers are about 35 times more likely to die from heat-related causes than workers in other sectors.  

• These cascading effects can overwhelm entire farms or regions, highlighting systemic risk  

• A significant number of countries cannot meet healthy dietary needs through domestic production alone. Starchy staple production is insufficient in key regions including Western Asia, the Middle East and North Africa, the Caribbean and Central America 

• Many countries rely on producing only a limited number of crops or food groups, reducing agricultural diversity and making food systems more vulnerable to climate and market shocks 

The pattern is clear: countries that rely heavily on food imports are the most exposed, and climate change is making that exposure worse. When harvests fail or supply chains are disrupted, import-dependent regions face the sharpest price spikes and the deepest nutritional shortfalls. Global food systems were already structurally fragile – extreme heat is making it worse. 

Accelerating Climate Change 

Climate change is making extreme heat worse and happen more often, reducing agricultural productivity and pushing the global food system towards instability.  The Nature Food study highlights that climate-related disruptions such as heatwaves, droughts, and shifting agroecological zones (shifts in the geographic areas suitable for growing specific crops due to changes in temperature, rainfall, and soil conditions) are deepening existing inequalities in access to food. 

At the same time, rapid warming in polar regions is altering global atmospheric circulation patterns. This may intensify or reshape extreme weather events at lower latitudes. 

Together, these interconnected processes show how climate and polar change are reinforcing risks to the global food system. 

Regional Implications 

South Asia (Bangladesh, Pakistan-Punjab):  

• Heatwaves reduce wheat, rice, and fruit production by up to 50% and also lower livestock output  

• This directly threatens staple food availability while reducing farm-based household incomes  

• By 2050, under the impacts of climate change (heat, drought and water scarcity), Bangladesh is expected to lose around 17% of its cultivated land. This would reduce rice production by about 30% and could displace nearly 30 million people, turning them into climate refugees.  

Sub-Saharan Africa (Ghana, Nigeria, Uganda, Tanzania):  

• Persistent deficits in dairy and vegetables, with high dependence on imports  

• Staples such as maize, millet, and sorghum are increasingly vulnerable to heat and drought stress  

• West Africa is seeing lower maize yields in about 85% of its harvested land, whereas Southern Africa and East Africa are affected in 29% and 32% of their maize-growing areas, respectively.  

• 91% of sub-Saharan African countries fall short of vegetable self-sufficiency already.  

Middle East & North Africa:  

• Several countries, including Yemen, Afghanistan, Qatar, and the UAE, show no food group self-sufficiency  

• Heavy reliance on imported wheat and other cereals increases exposure to global supply shocks  

• Morocco has already seen cereal yields fall by 43% due to prolonged drought and extreme heat. 

Caribbean & Central America:  

• Many countries are self-sufficient in only two or fewer food groups and depend heavily on imports  

• Staple foods such as rice, maize, and wheat-based products are largely sourced externally, for example from the United States  

South America (Brazil):  

• Extreme heat has contributed to around 10% losses in soybean production, alongside livestock stress  

• Key staples at risk include soy, maize, and rice, which are also important export crops  

Europe (Portugal):  

• Increasing heat-related wildfire risk is affecting agricultural land and rural livelihoods  

• Northern Europe shows weak production in fruits and vegetables, while some regions rely on imports of legumes and seeds  

• As of August 31, 2025, wildfires in Portugal had already burned more than 250,000 hectares. Numerous residents lost their homes, farmland, and businesses, prompting calls for the government to allocate €5 million per ministry to assist those affected. 

East & Southeast Asia (China & Vietnam):  

• Some countries show relatively high self-sufficiency, but heat exposure is increasing pressure on rice, vegetables, and fisheries systems  

• Climate stress is also contributing to shifting and unstable production zones 

Global Fisheries (Chile and Pacific regions):  

• Marine heatwaves are causing major losses in fish and aquaculture systems, including salmon farming in Chile  

• Only about 25% of countries are self-sufficient in fish and seafood, increasing global protein insecurity 

Health Implications: 

• Food price spikes driven by crop losses increase household poverty and reduce healthcare access  

• Chronic undernutrition contributes to long-term developmental and cognitive impacts in children  

• Increased vulnerability to infectious diseases due to weakened immune systems from malnutrition 

What You Can Do To Protect Yourself 

• Grow some of your own food – even a windowsill herb garden or a few vegetable plants reduces your household’s dependence on supply chains and connects you to where food comes from.  

• Join or start a community garden to build local food resilience, strengthen community networks, and make fresh produce more accessible to people who can’t grow at home (or don’t have a home) 

• Support local and diversified food producers by buying from farmers who grow a variety of crops (rather than just one or two). This helps build agricultural diversity that makes food systems more climate resilient  

• Reduce food waste – roughly a third of all food produced globally is lost or waster. Wasting less stretches food systems further and reduces the pressure on already stressed agricultural land 

Remember: Small actions add up – and they build the habits and networks that matter most when supply chains are under pressure. 

What System Changes Are Needed 

• Strengthen climate-resilient agricultural practices (such as heat-tolerant crop varieties, diversified cropping systems, agroforestry, improved irrigation efficiency, soil moisture conservation techniques, and climate-informed planting calendars) 

• Diversify food production systems and diets  

• Invest in early warning systems for extreme heat  

• Enhance international cooperation on food trade and resilience  

• Support interdisciplinary research and integrated risk governance 

Read more about health risks here. 

You already care about climate change. Now be the person who actually understands it. 

Free, credible, climate news straight to your inbox. Sign up for the Climate Alert Bulletin today.