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New Oxford University research finds nearly half the world’s population could be living with extreme heat by 2050 if global warming reaches 2 °C, underscoring urgent climate adaptation needs

A major new study led by researchers at the University of Oxford warns that the number of people living with extreme heat could almost double by 2050 if global temperatures rise to 2 °C above pre-industrial levels. The analysis, published in Nature Sustainability, projects that up to 3.79 billion people, nearly 41 % of the world’s population, would experience dangerously high heat, with far-reaching impacts on health, infrastructure, and energy systems.

Regional and global impacts of rising extreme heat

The researchers have found that the Central African Republic, Nigeria, South Sudan, Laos, and Brazil are predicted to experience the largest increases in dangerously hot temperatures, but the largest affected populations will be in India, Nigeria, Indonesia, Bangladesh, Pakistan, and the Philippines.

In colder climates, the public will experience a much larger relative increase in uncomfortably hot days, with some cases more than doubling.

Compared with the 2006–2016 period, when the global mean temperature increased by 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.

Even a moderate increase in temperature in countries designed for cold conditions is likely to have severe impacts compared to regions with greater resources, adaptive capacity, and embodied capital to manage heat.

Extreme heat increases the risk of heat exhaustion, heatstroke and dehydration, and can worsen heart, lung and kidney conditions, leading to higher hospital admissions and deaths during heatwaves. The health impacts fall most heavily on older people, children and those with existing illnesses, and place a growing strain on health systems as temperatures continue to rise.

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.

‘To achieve the global goal of net-zero carbon emissions by 2050, we must decarbonise the building sector while developing more effective and resilient adaptation strategies.’

Dr Radhika Khosla, Associate Professor at the Smith School of Enterprise and the Environment and leader of the Oxford Martin Future of Cooling Programme, added: ‘Our findings should be a wake-up call. 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 politicians regain the initiative towards it.’

‘Our findings should be a wake-up call. 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 politicians regain the initiative towards it,’ added Dr Radhika Khosla, Associate Professor at the Smith School of Enterprise and the Environment.