A study from the University of Oxford, published in Nature Sustainability, warns that by 2050 almost half of the world’s population (about 3.8 billion people) will live under conditions of extreme heat if the planet reaches 2°C of global warming, a scenario scientists consider increasingly likely.
In 2010, 23% of the world’s population was exposed to extreme heat. In the coming decades, the figure will rise to 41%, representing a drastic change in the daily lives of millions of people.
Most Affected Regions
The study indicates that the 20 countries with the greatest variations in cooling degree days (CDD) are developing nations, mainly in Africa, Central America, South America, and Southeast Asia.
- South America: Brazil, Venezuela, and Paraguay will be the most affected.
- Central America: Honduras, Guatemala, and Nicaragua will experience the greatest changes.
- Other continents: countries near the Equator and subtropical latitudes concentrate the highest risk.
Even countries with cold climates will see significant changes: Austria and Canada could double their hot days, while Ireland could record an increase of 230%.
Impact in Latin America
The report comes months after another study revealed that heat-related mortality increased by 103% between 1990 and 2021 in Latin America and the Caribbean. Additionally, extreme heat cost the region about 855 million dollars annually between 2015 and 2024.
Economic and Energy Consequences
The rise in temperatures will strain the economic development of regions and trigger the demand for energy for cooling and heating, increasing associated emissions.
Spanish researcher Jesús Lizana, the lead author of the study, explained that most changes in demand occur before reaching 1.5°C of warming, which requires implementing adaptation measures now.
Meanwhile, Professor Rahika Khosla warned that exceeding 1.5°C will have an unprecedented impact on sectors such as education, health, migration, and agriculture.
Health Risks
Extreme heat poses a direct threat to health:
- Heat stroke: a medical emergency with a risk of death, characterized by body temperature >40°C, dry skin, and confusion.
- Heat exhaustion: intense thirst, fatigue, dizziness, headache, and excessive sweating.
- Cardiovascular problems: vasodilation increases cardiac effort, with a risk of tachycardia and heart attacks.
- Kidney damage: dehydration can lead to kidney failure.
- Respiratory problems: hot air makes breathing difficult, worsening conditions like COPD.
- Neurological alterations: confusion, disorientation, and loss of consciousness.
The Oxford study reinforces the urgency of moving towards sustainable development with net-zero emissions. Extreme heat is not just an environmental challenge but also a social, economic, and health issue.
Early adaptation and emission reductions are the only ways to mitigate a future where nearly half of humanity will live under dangerous temperatures.
