Singapore’s heatwave plan and the push for climate resilience

[SINGAPORE] The Republic's recently announced heatwave plan sends a strong message that excessive heat is something we must all prepare for. According to the plan unveiled on March 19, cooling centers would be opened islandwide just before a heatwave begins to provide relief from the heat.

The plan also outlines a nationwide strategy for how various sectors should behave during a heatwave, from eldercare facilities limiting outdoor activities in the afternoon to schools perhaps shifting to home-based learning if necessary.

The move comes as Singapore, like many cities worldwide, grapples with the escalating effects of climate change. Cities from Tokyo to Paris have implemented similar heat mitigation strategies, reflecting a growing recognition that urban populations are particularly vulnerable due to the urban heat island effect. Singapore’s proactive stance aligns with global best practices, though experts emphasize that long-term adaptation will require both infrastructure changes and shifts in public behavior.

The new national response plan is a positive first step in ensuring that people take the threat seriously. However, we should not wait till the national heatwave plan is implemented before beginning to create heat resilience. People can start preparing for greater temperatures by doing things like exercising to increase their tolerance for hot weather.

Beyond individual actions, urban design will play a critical role in mitigating heat stress. Initiatives like increasing green cover, implementing cool roofs, and enhancing natural ventilation in public housing estates are already underway. For instance, the Housing Board’s Cool Towns project in Tengah incorporates shading, wind corridors, and water features to lower ambient temperatures. Such innovations could serve as blueprints for future neighborhoods as Singapore balances development with livability.

For starters, we should keep an eye out for society's most vulnerable members, particularly throughout the warm months of March to mid-year. For example, community leaders can be trained to recognize those suffering from heat exhaustion.

Heatwaves in Singapore are declared when the highest daily temperature over three consecutive days is at least 35 degrees Celsius, with an average daily temperature of at least 29 degrees Celsius. It has been relatively unusual in Singapore, with only six documented so far. The last episode happened in 2016.

However, climate models suggest these thresholds may be breached more frequently in the coming decades. A 2023 study by the Centre for Climate Research Singapore projected that by mid-century, the frequency of heatwaves could increase fourfold under high-emission scenarios. This underscores the urgency of preemptive measures, not just reactive ones, to safeguard public health and productivity.

However, just because there isn't a heatwave doesn't mean the country is safe. People are constantly exposed to excessive humidity, which causes sweat to escape more slowly, exacerbating their discomfort.

On numerous days, the temperature exceeds 34 degrees Celsius, particularly during the hot season from March to May. During this time, persons conducting strenuous work are at high risk of heat injury, exhaustion, and accidents.

Singapore is located in the tropics, and many residents have become accustomed to the heat and humidity. The chronic heat pain has not yet peaked, unlike other countries in the region that have seen temperatures above 40 degrees Celsius.

For example, a blistering heatwave blasted through Southeast Asia in early 2024. Between January and mid-April 2024, Malaysia reported at least 45 occurrences of heat-related illnesses, with two deaths. Heatstroke claimed the lives of 61 Thais by May 2024.

Furthermore, many Singapore residents can easily escape the heat by visiting an air-conditioned mall or taking a bus. As a result, we may mistakenly believe that we are safe from harm.

According to Dr Joshua Sim, a senior research fellow and historian of heat and health at the National University of Singapore, most residents here do not regard heat to be an oppressive threat, unlike persons living in informal settlements in rural areas in other nations.

This was the sentiment he gained after chatting with people as part of a study to better understand the thermal comfort of inhabitants living in various apartment types, ranging 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 told me. This involves turning up the air conditioning and fan, taking a cool shower, and drinking cold water.

However, as global greenhouse gas emissions continue to rise and temperatures rise, Singapore's heat issue may deteriorate further. Temperature records have already been shattered during the last decade, with 2024 ranking as Singapore's warmest year, along with 2016 and 2019. In May 2023, the mercury rose to 37 degrees Celsius, a 40-year high.

According to Singapore's third national climate change study, temperatures could exceed 35 degrees Celsius for 47 to 189 days per year by 2050. At the same time, at least 317 nights every year are projected to be warm, with temperatures reaching 26.3 degrees Celsius.

Rising temperatures and humidity, exacerbated by the urban heat island effect, are undoubtedly the most apparent climate impacts facing Singapore right now. The urban heat island is a phenomena in which cities are warmer than rural areas because buildings and roads retain heat.

Singapore is not vulnerable to other climate-related disasters, such as typhoons and wildfires. Extreme heat displays softly in comparison to other calamities, hence it has taken some time to raise awareness of this issue.

Until recently, heat stress in Singapore was mostly seen as a "military problem". Since the late 1970s, the Singapore Armed Forces has conducted several research projects to develop strategies to alleviate the SAF's high incidence of heat injuries.

According to a 2023 historical assessment of heat injuries in the SAF, the military reported 100 to 200 occurrences per year for decades until reducing them to 20 in 2011.

Later, the focus shifted to construction workers, and a 2022 NUS study discovered that they were subjected to high heat stress conditions multiple times each year after measuring the ambient conditions at 19 outdoor worksites.

In October 2023, the Ministry of Manpower made it essential for outdoor workers to take breaks every hour when it became too hot. For the general public, a nationwide heat stress alert was issued in mid-2023 to guide people participating in outdoor activities.

It is expected to become hotter, and the push to strengthen society's resilience to heat must continue. There are several ways to tackle heat without being overly reliant on air-conditioning or avoiding the outdoors.

Doctors and heat health specialists have encouraged using exercise to increase tolerance for hot conditions. Aerobic workouts such as jogging, cycling, and skipping rope help increase heart function, which improves the body's ability to regulate temperature. Researchers are also working on ways to help individuals deal with the heat at home without relying too heavily on air conditioning.

For the first time, researchers have ventured into flats to see how people deal with hot weather at home, with the goal of developing more household cooling systems in the future.

For two weeks, researchers from NUS and the Singapore University of Technology and Design, including Dr Sim, monitored the thermal comfort of every participating resident using skin temperature sensors, wearables, and survey responses.

Residents should also keep an eye out for one another during hot weather. It doesn't hurt to check up on senior neighbors and those with disabilities who may require assistance transferring to a more ventilated spot. With Singapore entering the hottest part of the year, now is the time to begin building more heat resilience.