Climate Change Threatens Global Food Security: Brazil's Case Study in Extreme Heat Impact

Extreme Heat Waves in Brazil: A Case Study in Agricultural Collapse

Two years ago, on April 25, 2024, an intense heat wave engulfed much of Brazil, capping five days of sweltering temperatures in the central and southern regions. The event followed another extreme heat wave that had devastated southern Brazil just weeks earlier. The heat index in Rio de Janeiro reached a record 144.1°F in March 2024—the highest in a decade.

These events were part of a prolonged cycle of severe heat waves that have repeatedly struck one of the world’s largest agricultural producers over recent years. The consequences have been devastating:

• Crop Yields Plummet: Soy and corn harvests in southeastern states like São Paulo dropped sharply. Peanuts, potatoes, sugarcane, and arabica coffee also suffered widespread losses.
• Livestock Under Stress: In the central-western region, droves of pigs endured severe heat stress for nearly a year.
• Supply Chain Disruptions: A blocked atmospheric cold front triggered catastrophic rainfall and flooding in Rio Grande do Sul, the southernmost state. This disrupted the supply chain and markets for pink shrimp across Brazil.

UN Report Highlights Global Agricultural Crisis

A new joint report by the World Meteorological Organization (WMO) and the Food and Agriculture Organization of the United Nations (FAO) documents these impacts. Released on April 23, 2025, the report merges weather and agricultural data to analyze how extreme heat is destabilizing global food systems and outlines strategies for sustainable food production in a warming world.

Brazil serves as the report’s sole country-level case study, reflecting its critical role in global agriculture and the disproportionate pressure its exports face from rising temperatures and climate variability, including the oscillating effects of El Niño and La Niña.

Global Examples of Agricultural Collapse Under Extreme Heat

The report also examines extreme heat events in other nations:

• Chile (2016): Warming ocean temperatures triggered massive algae blooms, killing an estimated 100,000 metric tons of farmed salmon and trout—the largest aquaculture mortality event in history.
• U.S. Pacific Northwest (2021): One of the strongest heat waves on record destroyed raspberry and blackberry harvests, reduced Christmas tree timber volume by 70%, and contributed to a 21–24% increase in North American forest area burned due to extreme heat, vegetative drying, and wildfires.
• India (2022): A record heat wave reduced wheat yields by 9–34% across over a third of Indian states. Heat-stressed dairy animals produced up to 15% less milk, and cabbage and cauliflower yields were halved.
• Kyrgyzstan (Spring 2023): In the Fergana mountain range, spring temperatures surged 50°F above seasonal averages, triggering a locust outbreak and causing dramatic declines in cereal harvests—a region once known for year-round snow.

Human-Caused Warming Accelerates Agricultural Threats

The report underscores that human-induced climate change is accelerating at an unprecedented rate. The past 11 years have been the warmest on record, intensifying the frequency and severity of extreme heat events that threaten global food security.

"The compounding effects of extreme heat are reshaping agricultural systems worldwide. This report provides critical insights into how we can adapt food production to survive—and thrive—in a hotter world."

As extreme heat becomes the new baseline, the report calls for urgent adaptation measures to protect food systems, reduce vulnerability, and ensure sustainable agricultural practices in the face of a rapidly changing climate.