Overview
- The peer-reviewed Nature Sustainability paper estimates about 41% of the global population—3.79 billion people—could be exposed to extreme heat by mid-century under a 2°C scenario.
- Exposure rises sharply before 1.5°C of warming, with projections of roughly 2.8 billion people living in extreme-heat regions by 2030, underscoring immediate adaptation needs.
- Cooling demand is set to surge in large tropical countries including India, Nigeria, Indonesia, Bangladesh, Pakistan and the Philippines, where many lack access to air conditioning.
- The biggest increases in dangerously hot days are projected in the Central African Republic, Nigeria, South Sudan, Laos and Brazil, while colder nations see declining heating needs yet remain vulnerable to hotter extremes.
- The analysis uses the Met Office’s HadAM4 climate model and provides open-source ~60‑km maps and degree‑day datasets, identifying extreme-heat regions as those exceeding 3,000 cooling degree days.