Extreme heat is now the fastest-growing climate disaster across Asia-Pacific, with millions facing chronic exposure to dangerous temperatures by century’s end. A new UN report released in November 2025 warns that South and Southwest Asia could experience more than 300 days of severe heat stress annually, while heat-related deaths across the region may double by 2050. The Asia-Pacific Disaster Report 2025: Rising Heat, Rising Risk marks a fundamental shift in the region’s disaster landscape, where heatwaves are now surpassing traditional threats like cyclones and droughts in frequency and impact.
The report states that the year 2024 offered a clear signal of this trend. It was the hottest year ever recorded, and countries across the region faced severe heat episodes. Bangladesh saw a heatwave that affected around 33 million people. India recorded around 700 deaths linked to heat.
The report presents new projections on future risk. By 2100, the region’s disaster losses could rise from 418 billion dollars under today’s trend to 498 billion dollars under a high-emissions path. The number of days above critical heat thresholds is expected to rise sharply. South and Southwest Asia, parts of Southeast Asia and northern and eastern Australia are moving toward chronic heat exposure.
Urban areas face some of the sharpest increases. Cities such as Delhi, Karachi, Dhaka, Manila, Jakarta, Seoul, Beijing, Tokyo and Phnom Penh could see temperatures climb an extra two to seven degrees Celsius on top of global warming. This rise is linked to the urban heat island effect, which traps heat in dense built-up areas. Children, older adults and outdoor low-wage workers are at the highest risk.
“Heat knows no borders; therefore, policy responses must anticipate impacts, reduce exposure and vulnerability at scale and safeguard those most at risk,” said UN Under-Secretary-General and ESCAP Executive Secretary Armida Salsiah Alisjahbana.
What the new analysis shows
The report tracks extreme heat through a heat index. This combines temperature and humidity to show how hot it feels. A heat index of 35 degrees Celsius is considered severe heat stress. Prolonged exposure at 41 degrees Celsius is considered extreme danger.
ESCAP used four thresholds: 35, 37, 39 and 41 degrees Celsius. South and Southwest Asia fall into the two highest risk categories. In India, Pakistan and Bangladesh, people may endure more than 300 days each year with a heat index above 35 degrees. Many regions could face more than 200 days above 41 degrees.
Southeast Asia also shows sharp increases. Nearly a third of its population could be exposed to extreme heat in a business-as-usual path. South and Southwest Asia would see the largest share of people exposed across all scenarios, with more than 40 percent facing heat index levels above 35 and 41 degrees.
The shift marks a major change in the region’s disaster profile. The report notes that cyclones and droughts once dominated disaster losses. Extreme heat is now driving a growing share of climate-linked events. In 2024, more than 180 natural hazards and climate-linked events were recorded. Heatwaves were among the most damaging.
Human consequences of rising heat
The report outlines clear health impacts. Extreme heat places severe strain on the body. It disrupts temperature regulation and affects the cardiovascular and respiratory systems. It increases the risk of heatstroke, kidney injury and other conditions. Long exposure can also lead to lasting cognitive and cardiovascular impacts.
South and Southwest Asia carry the highest exposure. More than 40 percent of the population could face heat index levels above 35 and 41 degrees in both medium- and long-term futures. Heat-related mortality could double by 2050.
The urban poor face the greatest danger. Many live in crowded neighbourhoods with little shade, limited airflow and lower access to cooling and healthcare. In Bandung, Indonesia, a study found temperature gaps of up to seven degrees Celsius between the hottest and coolest neighbourhoods.
As temperatures rise, heat interacts with poor air quality. Droughts and wildfires release fine particulate matter and gases such as carbon monoxide and nitrogen oxides. These pollutants create a feedback loop that worsens both heat and health risks.
Despite this growing danger, only about half of global meteorological services issue warnings for extreme temperatures. The report states that expanding heat-health warning systems in 57 countries could save around 100,000 lives each year.
“Heat knows no borders; therefore, policy responses must anticipate impacts, reduce exposure and vulnerability at scale and safeguard those most at risk. With urgency, clarity and cooperation, lives and livelihoods across the region can be protected,” said Armida Salsiah Alisjahbana.
Economic pressures tied to rising heat
The report tracks economic impacts as well. Heat stress reduces outdoor working hours, especially in agriculture, construction and industry. These sectors employ large rural workforces with limited ability to adapt.
Across Asia and the Pacific, working hours lost to heat stress are projected to rise from 3.75 million to more than 8.1 million full-time job equivalents between 1995 and 2030. This loss affects income and slows economic growth.
The region also faces growing threats from multiple hazards, including earthquakes, tsunamis, landslides, floods and storms. These events damage transport, energy, water and telecommunications networks. Using the Global Risk Model, the report estimates long-term disaster costs as average annual loss. These costs are set to increase under all future scenarios, reflecting rising pressure from climate change and limited adaptation.
Losses under today’s climate are estimated at 418 billion dollars. A moderate climate path raises that figure to 432 billion dollars. A high-emissions path pushes projected losses to 498 billion dollars.
What countries plan to do
The report outlines several steps that could reduce future losses. It calls for governments to place heat at the centre of multi-hazard planning and invest in early warning systems. These systems should use common metrics, interoperable alerts and trusted local communication.
ESCAP plans three regional efforts to support these goals. The first aims to expand social protection schemes that can respond to heat stress. The second seeks to create cross-border green cooling corridors. The third focuses on using space-based tools to strengthen heat preparedness and early warning.
The report was launched at the Ninth Session of the Committee on Disaster Risk Reduction, held in Bangkok. The meeting runs through 28 November 2025 and brings together governments to assess the region’s rising risks and consider forward-looking solutions.
Extreme heat is already changing daily life across Asia and the Pacific. The data shows that the region is entering a period of chronic exposure, and people in cities and rural areas are feeling the effects. The report highlights a clear path: better heat planning, improved alerts and stronger protection for those most exposed.
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