National heatwave response plan a signal that Singapore should start taking heat seriously

SINGAPORE – The Republic’s recently unveiled heatwave plan sends a strong signal that extreme heat is something we all need to prepare for.

Under the plan revealed on March 19,

cooling centres will be opened islandwide

just before a heatwave kicks in to provide a respite from the heat.

The plan also sets out a national approach to how various sectors should respond during a heatwave, from eldercare centres suspending outdoor activities in the afternoon to schools possibly shifting to home-based learning if the need arises. 

The new national response plan is a good first step to ensuring people take the threat seriously.

But we should not wait until the national heatwave plan kicks in to start building resilience to heat.

People can start preparing for higher temperatures by, for example, using exercise as a tool to raise tolerance for warmer weather.

We should also look out for the more vulnerable in society, especially during the hotter months from March to mid-year, for a start. For example, neighbourhood representatives could be equipped with skills to identify people with heat exhaustion.

Heatwaves are declared in Singapore when the highest daily temperature over three consecutive days is at least 35 deg C, with the mean temperature each day being at least 29 deg C.

Such events have been relatively rare in Singapore, with just six recorded heatwaves so far. The last episode occurred in 2016.

However, this does not mean the country is out of the woods when there is no heatwave. Each day, people are exposed to high humidity where sweat does not evaporate as quickly, adding to discomfort.

The mercury exceeds 34 deg C on many days, especially during the March-to-May hot season. During this period, the risk of heat injuries, exhaustion and accidents among those doing strenuous work is high.

Singapore is located in the tropics, and many people living here have grown accustomed to the heat and humidity.

The chronic discomfort with heat in Singapore also has not reached a peak yet, compared with other countries in the region that have experienced temperatures exceeding 40 deg C.

For example, South-east Asia

was in early 2024 swept by a sweltering heatwave.

In Malaysia, at least 45 cases of heat-related illnesses were reported between January and mid-April 2024, with two deaths. By May 2024, 61 people had died from heatstroke in Thailand.

Moreover, many residents in Singapore can easily pop into an air-conditioned mall or a bus to escape the heat.

And so, it is easy to assume we are out of danger’s reach.

As Dr Joshua Sim, a senior research fellow and historian of heat and health at the National University of Singapore, observed, most residents here do not consider heat an oppressive threat compared with people living in informal settlements in rural areas in other countries.

This was a sentiment he got after speaking with residents as part of a study to understand the thermal comfort of residents living in various apartment types, from three-room flats to condominiums.

“It’s hot, definitely, but there are a lot of things they can do to mitigate it at home,” he said. This includes things like cranking up the air-conditioner and fan, taking a cool shower and drinking cold water.

But with global greenhouse gas emissions continuing to rise and sending temperatures soaring, the heat situation in Singapore could get worse.

Already, temperature records have been broken over the past decade, and

2024 was Singapore’s warmest year,

tying with 2016 and 2019. In May 2023, the mercury spiked to 37 deg C, a 40-year high.

By 2050, between 47 and 189 days in a year could see temperatures exceeding 35 deg C, according to Singapore’s Third National Climate Change Study. At the same time, at least 317 nights a year are expected to be warm, reaching at least 26.3 deg C.

In Singapore, rising temperatures and humidity – compounded by the urban heat island effect – are arguably the most tangible climate impacts faced here currently. The urban heat island refers to a phenomenon where urban areas are warmer than rural areas as buildings and roads retain heat.

Singapore is not exposed to other climate-driven disasters such as typhoons and wildfires.

Compared with those disasters, extreme heat manifests silently, and so it has taken a while to highlight this problem.

In Singapore, heat stress was primarily considered a “military problem” until recently. Since the late 1970s, various research works have been undertaken by the Singapore Armed Forces to create policies to address the SAF’s high incidence of heat injuries.

For decades, the military recorded 100 to 200 heat injury cases per year until they were reduced to 20 per year in 2011, stated a 2023 historical study about heat injuries in the SAF.

Later, the focus was turned to construction workers, and a 2022 NUS study found that they were exposed to high heat stress conditions several times in the year, after the environmental conditions of 19 outdoor worksites were measured.

In October 2023, the Ministry of Manpower made it

mandatory for outdoor workers to be given breaks every hour

when it gets too hot. For the wider population, a national heat stress advisory was released in mid-2023 to guide those doing outdoor activities.

It is set to get hotter, and the momentum to increase society’s resilience to heat must not stop.

There are several ways to tackle heat without being overly reliant on air-conditioning or avoiding the outdoors.

Doctors and heat health experts have advocated the use of exercise as a tool to raise tolerance for the warmer weather. Aerobic exercises such as running, cycling and skipping rope can improve a person’s heart function and that will, in turn, improve the body’s ability to regulate its temperature.

Studies are also being done to help people weather the heat at home, without relying on air-conditioning too much.

For the first time, researchers here have been venturing into flats to find out how residents cope with the hot weather at home – with the aim of devising more domestic cooling solutions in the future.

Researchers from NUS and the Singapore University of Technology and Design, including Dr Sim, have been tracking the thermal comfort of every participating resident for two weeks with the help of skin temperature sensors, wearables and survey responses.

Residents should also watch out for one another during the hotter periods. It does not hurt to check in on elderly neighbours and those with disabilities, who may need help moving to a better ventilated location.

With Singapore entering the hotter part of the year now, the time is ripe to start building more resilience to heat.