Almost Half The World's Population Will Be Living In Extreme Heat By The Year 2050

A new University of Oxford study finds that almost half of the global population (3.79 billion) will be living with extreme heat by 2050 if the world reaches 2.0°C of global warming above pre-industrial levels: a scenario that climate scientists see as increasingly likely.

Key Findings From Oxford Study

Most of the impacts will be felt early on as the world passes the 1.5°C target set by the Paris Agreement, the authors warn. In 2010, 23% of the world's population lived with extreme heat, and this is set to grow to 41% over the next decades. There will be grave implications for humanity, with the Central African Republic, Nigeria, South Sudan, Laos, and Brazil seeing the most significant increases in dangerously hot temperatures. The largest affected populations will be in India, Nigeria, Indonesia, Bangladesh, Pakistan, and the Philippines, the study predicts.

Compared with the 2006-2016 period, when the global mean temperature increase reached 1°C over pre-industrial levels, the study finds that warming to 2 °C would lead to a doubling in Austria and Canada, 150% in the UK, Sweden, Finland, 200% in Norway, and a 230% increase in Ireland. Given that the built environment and infrastructure in these countries are predominantly designed for cold conditions, even a moderate increase in temperature is likely to have disproportionately severe impacts compared with regions that have greater resources, adaptive capacity, and embodied capital to manage heat.

Lead author, Dr Jesus Lizana, Associate Professor in Engineering Science, said: "Our study shows most of the changes in cooling and heating demand occur before reaching the 1.5ºC threshold, which will require significant adaptation measures to be implemented early on. For example, many homes may need air conditioning to be installed in the next five years, but temperatures will continue to rise long after that if we hit 2.0 of global warming."

What Is The Solution?

Overshooting 1.5°C of warming will have an unprecedented impact on everything from education and health to migration and farming. "Net zero sustainable development remains the only established path to reversing this trend for ever hotter days. It is imperative that politicians regain the initiative towards it,” according to the study's authors. The projected increase in extreme heat will also lead to a significant rise in energy demand for cooling systems and corresponding emissions while demand for heating in countries like Canada and Switzerland will decrease.

The study’s results are measured in ‘cooling degree days’ and ‘heating degree days’ - metrics commonly used in climate research and weather forecasting to estimate whether cooling or heating is needed to keep people within safe temperatures. “This computational efficiency enables the generation of very large, high-resolution climate projections across different global warming levels: from 1 °C (2006–2016) to 1.5 °C and 2.0 °C independently of the timing of these,” explains Dr Jesus Lizana.

The study also includes an open-source dataset of global heating and cooling demand, comprising 30 global maps at ≈60km resolution that capture climate intensity in ‘cooling degree days’ and ‘heating degree days’ worldwide. This dataset provides a strong foundation for incorporating accessible climate data into sustainability planning and development policy.

For the "middle-of-the-road" shared socioeconomic pathway (SSP2-4.5), people living in extreme heat regions (>3,000 CDD) are projected to increase from 23% (1.54 billion — blue line) in 2010 to 41% (3.79 billion - red line) by 2050.

Canada experiences the steepest drop, with (-850) fewer HDDs (Heating Degree Days), followed by the Russian Federation (-752) and Finland (-614). Other northern and colder-climate nations such as Sweden, Norway, Mongolia, and the United States also show significant declines, reflecting their traditionally high heating needs. Even smaller countries like Kyrgyzstan, Austria, and Belarus register notable reductions.

Overall, this pattern highlights how warming disproportionately reduces heating demand in colder regions, potentially lowering energy costs for households but also signaling shifts in climate norms, ecosystems, and infrastructure planning in these countries.

Sources:

• https://www.ox.ac.uk/news/2026-01-26-global-population-living-extreme-heat-double-2050
• https://www.smithschool.ox.ac.uk/news/global-population-living-extreme-heat-double-2050-oxford-study

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