Extreme heat events are threatening the livelihoods and health of more than 1 billion people. The warning comes from the report Extreme Heat and Agriculture, released this Wednesday (22) by the Food and Agriculture Organization of the United Nations, FAO, and the World Meteorological Organization, WMO. According to "UN News", the study analyzed the impacts of a long and severe extreme heat event that hit much of Brazil between 2023 and 2024. In some places, over several months, daytime maximum temperatures exceeded the climatological average by 5 °C, with multiple episodes of heat waves recorded. The impacts on Brazil's main crops, soybeans and corn, were significant, as the heat waves coincided with the development cycles in the main producing areas of the Northeast, Midwest and Southeast. :: 10% Drop in Soybean Production Analyses indicate that maximum daytime temperatures exceeded the critical threshold for soybeans, of 30°C, on more than 60% of the days between October 2023 and May 2024. Due to heat stress, the final harvest was 147.7 million tons, a reduction of almost 10% compared to initial expectations, according to data from the Ministry of Agriculture, Livestock and Supply. Soybeans are sensitive to high temperatures during the reproductive and grain-filling stages, when excessive heat can cause flower abortion, pod drop, and grain malformation, which reduces overall productivity. Other crops such as peanuts, corn, potatoes, sugarcane, and beans faced an increase in pests and diseases. :: Pigs and Cows Under Heat Stress The livestock sector also came under severe pressure. In the Central-West region, pigs, one of the animals most sensitive to heat, were under intense heat stress for 20 or more days each month for most of 2023–2024. Heat stress in pigs causes a slowdown in feed intake and weight gain. These effects can be offset by prolonging the growth cycle, but this increases costs. In the case of cattle, heat stress results in a drop in milk production, and these losses cannot be recovered. Prolonged periods of exposure to extreme heat, in both species, can cause long-term physiological damage and impair reproduction, representing an additional and irreversible economic loss for producers. Warmer water limits oxygen for fish. Rainbow trout and Atlantic salmon farming were also impacted. As water temperatures rise, these species suffer double stress, as warmer water contains less oxygen while simultaneously accelerating the fish's metabolism, thus increasing their oxygen demand. Under greater physiological stress, the fish feed less and become more susceptible to diseases caused by opportunistic microorganisms. During 2023 and 2024, water temperatures reached their highest level in ten years at the experimental salmon farming station in Campos do Jordão. The elevated temperatures caused high mortality rates in the fish, from embryos to adults. :: Forest fires and catastrophic rainfall The heat also caused catastrophic forest fires, which devastated an area equivalent to the size of Italy and resulted in severe air pollution from microparticles. The climate event that caused the heat also resulted in catastrophic rainfall and flooding in Rio Grande do Sul between April and May 2024. The state is responsible for more than 70% of Brazilian rice production, and the floods caused a 3.6% drop in productivity. The FAO and WMO report states that the frequency, intensity, and duration of extreme heat events have greatly increased in the last half-century, with worrying impacts on agri-food systems and landscapes. Extreme heat refers to situations where daytime and nighttime temperatures rise above usual ranges for a prolonged period. This causes physiological stress and direct physical damage to food crops, livestock, fish, trees, and humans.
This text was translated by machine from Brazilian Portuguese.