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Preparing for a future of extreme heat waves
People across Asia have eagerly awaited the end of heat-wave season, which now appears to be drawing to a close. In my home country, the Philippines, the first typhoon of the year arrived in late May, lowering temperatures that had climbed to nearly 50° Celsius (122° Fahrenheit). Over the previous few months, the record-breaking heat led to school closures, a spike in emergency-room visits, reduced productivity, and a return to remote work.
While the public-health effects and economic impact of extreme heat waves can be difficult to measure, the speed at which they are forgotten is alarming. This mirrors the cycle of panic and neglect that often follows pandemics: societies forget the lessons of past health crises and are caught unprepared when the next one arrives.
Just as we must improve pandemic preparedness, we must mitigate the health risks posed by life-threatening temperatures. As climate change accelerates, heat waves are expected to become increasingly frequent and intense, especially in Asia. To survive this “new normal,” we cannot rely on inadequate public-health guidelines like drinking more water and staying in air-conditioned spaces, as if the vast majority of the world’s population has access to air conditioning or even clean water. Nor is it acceptable to suggest that women should cope with extreme heat by not wearing underwear, as a former Philippine health minister recently suggested.
Instead, governments must adopt a more proactive approach and accelerate efforts to build heat resilience. By the time the next historic heat wave hits, all countries should have a national plan to address it, along with adaptation measures for local communities. In fact, every aspect of policymaking should be viewed through the lens of resilience. Beyond the health sector, the top priorities should be housing, transportation, and water—which are all targets under the Sustainable Development Goals.
Housing should come first. Many of Asia’s most vulnerable people live in poorly ventilated public housing or densely populated slums. Globally, an estimated 1.6 billion people suffer from inadequate living conditions. Given that such surveys do not usually account for ventilation, this could well be an underestimate.
There are more viable options for adaptation than advising poor people to live in air-conditioned buildings. In addition to being costly, air conditioners consume vast amounts of electricity, with researchers estimating that they are responsible for 3.9 percent of global greenhouse-gas emissions. Instead of burning more fossil fuels to meet this increased energy demand, policymakers must reimagine urban development to protect both the planet and public health. For example, some countries in Asia, including Indonesia and Singapore, have begun using low-cost “cool roof” paint to lower indoor temperatures without air conditioners.
Transportation is another heat-sensitive sector. Whether riding in overcrowded buses or waiting for extended periods on sweltering train platforms, commuters in low- and middle-income countries are often exposed to extreme temperatures. Investing in sustainable transportation systems that also provide comfort during heat waves is crucial to achieving vital climate and public-health goals.
To build heat resilience, governments must also address the global water crisis. Although hydration is crucial for protection against extreme heat, nearly one-third of the world’s population does not have access to safe drinking water. Single-use plastic water bottles are not the answer; like air conditioning, they are costly, carbon-intensive, and polluting.
Heat-preparedness programmes must focus on highly vulnerable groups, such as farmers and fisherfolk, construction and factory workers, the elderly, and people with comorbidities. This effort must also be extended to prisoners, detained migrants, and psychiatric patients, all of whom are often confined to extremely hot, cramped spaces.
Like storm and pandemic-response protocols, heat preparedness must be embedded in health policies. To this end, Asian countries’ disease-surveillance systems should be updated to account for heat-related illnesses before the region endures another historic heat wave. Maintaining adequate supplies of medical equipment, from basic items like intravenous fluids to cooling vests, is also crucial.
Moreover, the potential effects of extreme heat must be integrated into the education and training of emergency doctors, community-health workers, and primary-care providers, who are often the first point of contact for underprivileged patients. Regrettably, the clinical management of heat-related illnesses like heatstroke was mentioned only in passing when I was a medical student.
Lastly, researchers must focus not only on the epidemiology of heat, but also the effectiveness of our policies and interventions. The National University of Singapore, for example, launched a research centre dedicated to heat resilience in 2023; my institute will complement this with a new initiative on planetary health that will help health systems and communities across Asia build climate resilience.
With global temperatures rising at an alarming rate, we have no choice but to adapt to a warmer world. At the same time, accelerating decarbonisation could enable us to reduce the frequency and intensity of extreme heat waves. By pressuring governments and corporations to stop burning fossil fuels, we can build true heat resilience and improve planetary health.