Romuel Delos Santos, 27, has spent the past year with a rail construction company in Metro Manila, Philippines, building on four years of prior experience in the sector.
Cutting, bending and installing steel bars at project sites often leaves him exposed to blistering heat. Despite being accustomed to such conditions, he developed heat rashes and persistent headaches last year after prolonged exposure to extreme temperatures.
To cope, Delos Santos drinks more water and takes regular breaks in shaded areas provided by his employer.
“I used to be able to endure the hot weather by wearing long-sleeved shirts, but now the heat just seeps through my clothing,” said Delos Santos. “The heat has gotten so much worse over the years. We can really feel the changes in the weather.”
Workers like Delos Santos are on the frontlines of a growing challenge playing out across Asia.
While climate change is often discussed in terms of storms, floods and rising sea levels, experts increasingly recognise that its effects on human health are becoming an important consideration. Extreme heat is one example of a broader set of climate-related health risks emerging across the region.
Asia experienced one of its warmest years on record last year, as temperatures continued to rise, ocean heat reached unprecedented levels and increasingly severe weather highlighted the growing impacts of climate change across the region, according to a new report from the United Nations-led World Meteorological Organization (WMO) released in June.
“Across Asia and the Pacific, heat is intensifying multi-hazard risks, intersecting with food systems, public health, infrastructure and oceans and placing new pressures on health and livelihoods,” said Armida Salsiah Alisjahbana, undersecretary-general of the United Nations and Executive Secretary of the Economic and Social Commission for Asia and the Pacific (ESCAP) in the report.
The annual mean temperature over Asia in 2025 was 0.96°C + 0.08 above the 1991 to 2020 average and ranked between the second and fourth warmest year on record, depending on the dataset used. Image: WMO
Heat’s hidden health burden
Since 2020, Southeast Asia has experienced repeated record‑breaking hot seasons, including the major heatwave in 2024 that disrupted schools and workplaces, strained power grids, and affected crops and ecosystems across the region.
In the Philippines, for instance, the number of cases of heat-related illnesses in 2024 reached 77, including those who may have died due to the hot weather.
Thailand confirmed that at least 30 fatalities happened due to heat-related causes across the nation in the same year, after which local authorities issued an extreme heat warning advising residents to remain indoors for their safety as temperatures surged. Vietnam declared a state of emergency in response to the abnormally high temperatures, which contributed to severe drought, disrupting agriculture in key producing regions, including parts of the Mekong Delta.
The wider Asian region had the second largest increase in heatwave exposure due to climate change in that period, following small island states, according to a report published in 2025 by Lancet, a peer-reviewed medical journal based in the United Kingdom. This finding signified a rapidly escalating health, social, and economic crisis, with climate change turning extreme heat from a seasonal nuisance into a structural threat to development and wellbeing, suggested the report.
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These deaths are typically recorded within healthcare systems under medical causes such as heart attack or stroke, rather than being classified as disaster-related deaths. As a result, the true mortality burden of heat is substantially underestimated in disaster statistics.
Juthamard Surapongchai, researcher and lecturer, Mahidol University, Gatorade Sports Science Institute
Yet unlike floods and storms, extreme heat often leaves no visible trail of destruction.
This is because disaster databases primarily capture direct, acute fatalities from sudden events such as floods and typhoons like drowning or traumatic injuries, which are immediately identifiable, said Juthamard Surapongchai, researcher and lecturer at Mahidol University’s Gatorade Sports Science Institute in Thailand.
In contrast, extreme heat often contributes to death indirectly by exacerbating underlying cardiovascular, renal, and respiratory conditions, Juthamard added.
“These deaths are typically recorded within healthcare systems under medical causes such as heart attack or stroke, rather than being classified as disaster-related deaths. As a result, the true mortality burden of heat is substantially underestimated in disaster statistics,” she told Eco-Business.
Jemilah Mahmood, executive director, Sunway Centre for Planetary Health at Sunway University Malaysia, noted how extreme heat is “very likely to rival or even exceed the death toll from typhoons, but it remains largely invisible in the statistics.”
“What makes heat particularly dangerous is that… risks escalate gradually until health systems, workers, and households are already under strain,” said Mahmood.
Why life and health insurers are paying attention
Delos Santos said that when heat-related symptoms persist despite resting in the shade, he has little choice but to seek medical treatment. But a visit to the doctor often costs him a day’s wages as well as out-of-pocket medical fees, as health insurance is not included in his employee benefits.
His experience reflects a wider regional problem. Across Asia, climate-related health risks are becoming an increasingly important consideration as temperatures rise, populations age and healthcare needs continue to grow.
The forthcoming Climate and Health in Asia report, authored by Forum for the Future and sponsored by AIA, examines how climate-related health risks are evolving across the region and highlights opportunities for governments, healthcare providers, communities and life and health insurers to strengthen resilience in a changing climate.
The report highlights opportunities for insurers to support climate-health resilience through health awareness, preventive health engagement, access to healthcare and collaboration across the broader health ecosystem.
Amita Chaudhury, group head of sustainability at AIA and chair of the UNEP FI Principles for Sustainable Insurance board, said climate-related health risks are encouraging organisations to think more broadly about health and wellbeing.
“This includes developing a better understanding of how extreme heat affects older adults, outdoor workers and people with chronic conditions and recognising that heat is not just a comfort issue but a health issue,” Chaudhury told Eco-Business.
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As climate-related risks evolve, there is a growing need to place greater emphasis on prevention, health engagement and helping people stay healthier for longer.
Amita Chaudhury, group head of sustainability, AIA
“As climate-related risks evolve, there is a growing need to place greater emphasis on prevention, health engagement and helping people stay healthier for longer,” said Chaudhury, adding that a better understanding of how climate-related factors influence health can inform more proactive approaches to wellbeing and support resilience over the long term.
Encouraging healthier lifestyles and proactive health management can help build resilience before health issues arise, according to Chaudhury. The report also underscores the importance of strengthening health awareness and preparedness so that people are better equipped to understand and respond to climate-related health risks.
Beyond individual policyholders, insurers can also work with healthcare providers to strengthen system-wide resilience, she said. This includes improving care coordination, supporting access to care, promoting preventive health approaches and encouraging healthy behaviours through wellness programmes that reward users for healthy habits like exercising, eating well, and tracking sleep.
The AIA-sponsored report noted that community-level support is equally important, particularly for vulnerable populations such as older adults and those with underlying health conditions.
Insurers can also contribute to the wider enabling environment through research, partnerships, and collaboration that deepen understanding of climate-health risks and support long-term resilience, the study suggested.
“By demonstrating commitment through their own operations and investments, insurers build the internal expertise and external trust needed to effectively engage with policyholders, healthcare providers, and the broader ecosystem on climate-health challenges,” the report noted.
Yet significant gaps remain in translating this potential into practice.
The report called extreme heat a “silent killer” that can exacerbate cardiovascular, respiratory, kidney, and mental health conditions, particularly among vulnerable populations.
But climate health still remains an evolving field in the region. While there is growing recognition that extreme heat affects outcomes, far less is understood about how these impacts vary across populations, geographies, and healthcare systems, or how prolonged heat exposure compounds chronic illness beyond acute heat stroke, according to the study.
While extreme heat is emerging as one of Asia’s most underestimated health challenges, it also provides a useful lens through which to understand the broader relationship between climate and health. These themes are explored further in Climate and Health in Asia, which will be launched on 26 August.
