TDS Desk:

Bangladesh is projected to be among the six countries most severely affected by extreme heat by 2050, according to a new international study led by researchers from the University of Oxford, United Kingdom.

The study, published on Monday in Nature Sustainability, warns that the global heatwave crisis is intensifying, with serious consequences for daily life, economies, and public health systems.

If current fossil fuel consumption continues, the proportion of the world’s population exposed to extreme heat could nearly double over the next 25 years. Should global warming reach 2°C above pre-industrial levels, around 41% of the world’s population, approximately 3.79 billion people, will live under extreme heat conditions by mid-century, compared with 23%, or about 1.54 billion, in 2010.

Using high-resolution climate and population models, the researchers assessed heatwave risks with the Cooling Degree Days (CDD) index, which measures the amount of cooling required to maintain safe indoor temperatures. Regions exceeding 3,000 CDDs per year were classified as “extreme heat–prone”. Based on this threshold, the countries with the largest populations exposed include India, Nigeria, Indonesia, Bangladesh, Pakistan, and the Philippines.

Lead author Dr Jesus Lizana of the University of Oxford noted that national average temperatures can mask the true risk. “Most people in Bangladesh live in areas where annual cooling demand exceeds 3,000 CDDs. This means prolonged and dangerous exposure to heat, which affects human survival, productivity, and health,” he said.

Bangladesh, already considered one of the world’s most climate-vulnerable countries, now faces an added dimension of heat stress. While attention has often focused on sea-level rise, cyclones, and flooding, extreme heat is emerging as a silent but deadly threat. Experts highlight that heatwaves increase the risk of heatstroke, cardiovascular stress, and kidney disease — particularly among the elderly, children, and low-income populations with limited access to cooling.

The Oxford-led study also predicts that rising temperatures will drive the fastest growth in cooling demand in low- and middle-income tropical and subtropical countries. In contrast, wealthier nations in the Global North are likely to experience reduced heating needs as winters become milder.

Per capita Cooling Degree Days are projected to rise most sharply in the Central African Republic, Nigeria, South Sudan, Laos, and Brazil. Conversely, countries such as Canada, Russia, Finland, Sweden, and Norway are expected to require less heating due to warmer winters.

By 2050, the share of the global population living in “very cold” regions is projected to fall from 14% to just 7%. Researchers also caution against a potential “cooling trap” in extreme heat–prone countries, where rising demand for air conditioning could increase energy use and, if met with fossil fuels, accelerate climate change further.

The findings underscore that the window to prevent the worst impacts of extreme heat is rapidly closing. Scientists say limiting global warming to 1.5°C could significantly reduce the number of people exposed to life-threatening heat.