Global Warming Intensifies Heat Stress Worldwide

Research published Monday highlights that countries like Mexico, Kenya, and Italy are experiencing extended periods of heat stress. This trend now affects regions previously untouched by such conditions. The change stems from the planet’s warming, fueled by fossil fuel combustion, noted in a study from the journal Nature Climate Change.

The study examines the ‘feels-like’ temperatures, offering a detailed look at how heat stress impacts humans. Researchers used the Universal Thermal Climate Index to analyze temperature, humidity, and wind speed, assessing the human body’s response. Humidity hampers sweat evaporation, a cooling mechanism, making humid heat waves potentially deadlier than dry ones.

Findings indicate increasing heat stress in already warm areas and new regions. Research suggests people globally faced an average of 41 more days of extreme heat in 2024. By century’s end, nearly two more months of superhot days could occur annually.

Specific areas, such as Southern Africa, Namibia, Angola, Eastern Africa including Tanzania, Kenya, and Uganda, along with parts of Mexico and Central America, may see 50 more days of strong heat stress than in the 1970s.

In Southern Europe, regions like Spain, Italy, Greece, and Turkey could experience up to 40 extra days of strong heat stress compared to the 1970s. The U.S., including Texas and Florida, faces 15 or more strong heat stress days, with Southern parts seeing up to 25 very strong heat stress days.

Rebecca Emerton, the study’s lead author, notes the increasing heat stress footprint, affecting traditionally cooler regions. The study reports that feels-like temperatures on the ten warmest nights each year have risen by 0.32 degrees Celsius per decade, faster than daytime increases. Tropical nights reference minimum temperatures of 20 degrees Celsius, affecting recovery from daily heat.

This heat stress expansion now affects one billion more people yearly than in the 1970s. The future depends on mitigating warming effects through strategies like heat health action plans and early warning systems.

Jennifer Francis, a climate scientist, emphasizes that the study reveals rising humidity’s role in increasing heat danger. Adaptation and mitigation are crucial to address future risks.