Extreme Heat to Affect 41% of Global Population by 2050

Nearly half of the world’s population could be living under extreme heat conditions by 2050 if global temperatures rise by 2°C above pre-industrial levels, according to a new study by scientists at the University of Oxford published in Nature Sustainability.

The research estimates that around 3.79 billion people — 41% of the projected global population — will experience dangerous heat exposure by mid-century, up sharply from 23% (1.54 billion people) in 2010. The alarming rise is attributed largely to continued dependence on fossil fuels such as coal, oil and gas.

Climate scientists warn that the world is on track to reach the 2°C threshold within the next 25 years unless rapid emissions cuts are implemented. Even before that, major impacts are expected as the planet breaches the 1.5°C limit set under the Paris Agreement.

Developing Nations to Bear the Brunt

The study highlights that countries including the Central African Republic, Nigeria, South Sudan, Laos and Brazil will witness the steepest increases in extreme heat days. In absolute numbers, the largest affected populations are projected to be in India, Nigeria, Indonesia, Bangladesh, Pakistan and the Philippines — raising serious concerns for public health, productivity and infrastructure resilience.

For India, already grappling with record-breaking heatwaves, the findings underscore the urgent need for climate-resilient urban planning, energy-efficient buildings and accelerated clean energy deployment.

Cold Countries Not Spared

Interestingly, nations traditionally known for colder climates are expected to see the sharpest relative increases in uncomfortably hot days.

Compared with the 2006–2016 baseline period, warming to 2°C could result in:

• 100% increase in Austria and Canada
• 150% increase in the UK, Sweden and Finland
• 200% increase in Norway
• 230% increase in Ireland

Researchers caution that buildings and infrastructure in these regions are largely designed to retain heat and minimise ventilation, making them especially vulnerable even to moderate temperature rises.

Buildings at the Centre of the Climate Challenge

The study stresses that heating and cooling dominate global building energy demand and emissions, making the sector critical to achieving climate targets.

Currently, heating accounts for about 45% of building-related emissions, while space cooling is projected to more than triple by 2050, expanding faster than any other building end-use. With millions of homes likely to require air conditioning in the coming years, unchecked growth in cooling demand could significantly worsen carbon emissions.

“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°C of global warming,” said Dr Jesus Lizana, lead author of the study and Associate Professor in Engineering Science at Oxford.

“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,” he added.

Implications for India’s Energy Transition

For India and other emerging economies, the findings reinforce the importance of sustainable cooling solutions, green buildings, district cooling systems and renewable-powered infrastructure. Public Sector Undertakings (PSUs) in power, renewables and urban development are expected to play a key role in enabling low-carbon cooling and climate-resilient housing.

Experts note that without urgent action, rising heat exposure could strain electricity grids, increase healthcare costs and widen socio-economic inequalities.

The Oxford study serves as a stark reminder that climate change is no longer a distant threat — and that decarbonising buildings must become a central pillar of global and national climate strategies.

The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy