Singapore is preparing to beat the heat with a national plan that will kick in before a heatwave is officially declared.
The plan, announced on March 19, includes measures such as opening cooling centres to the public when a heatwave is forecast. If the need arises, schools could also go on either partial or full home-based learning so as not to disrupt learning.
The plan was formulated by an inter-agency task force, called the Mercury Taskforce, which was specially created to help Singapore prepare for extreme heat.
The Straits Times explains what this taskforce is about and its role in helping Singapore prepare for a heatwave.
1. What is the Mercury Taskforce?
The Mercury Taskforce was set up in 2023, although it was revealed to the media only during the launch of the national heatwave response plan.
Led by the Ministry of Sustainability and the Environment and National Environment Agency (NEA), it is made up of 37 public agencies.
They include the health, social and family development, education, defence and manpower ministries, as well as People's Association and Sport Singapore.
The aim of the task force is to develop and implement action plans to minimise and manage the impact of a heatwave. The task force will also coordinate responses across the agencies.
When the weather forecast by the Meteorological Service Singapore (MSS) indicates a high likelihood of a heatwave in Singapore, a joint media advisory warning of impending high temperatures will be issued, said the task force.
The advisory will be in place until MSS forecasts that the high temperatures will subside.
2. Why do we need a Mercury Taskforce?
The task force said the warming trends highlighted in Singapore's Third National Climate Change (V3) underscore the critical need to increase public awareness and preparedness for heat.
Based on the V3 released in January 2024, Singapore residents can expect very hot days and warm nights to be the new normal by end-century, according to the study.
The projections show that by mid-century, between 47 and 189 days in a year will see temperatures exceeding 35 deg C while at least 317 nights are expected to be warm.
The average maximum temperature for each day could also rise between 0.5 deg C and 5.3 deg C, reaching a high of 36.7 deg C in the worst-case scenario.
While there are existing measures in place to protect certain segments of the community from rising temperatures, such as outdoor workers, the coordinated heatwave plan provides additional measures for all Singapore residents.
"In addition to the ongoing heat awareness and heat stress management measures, we may expect increasing occurrences of sustained high temperatures from time to time," the task force told The Straits Times.
"The coordinated heatwave response plans provide an additional layer of measures, such as the opening of community cooling spaces for people seeking heat respite and stepped-up communications and advisories to the public on how to manage the heat."
3. What is a heatwave? How does it differ from heat stress?
There is no universally accepted definition of a heatwave, but the World Meteorological Organisation considers such events to be periods of extreme day- and night-time temperatures with a duration of two days or more, said the task force.
In Singapore, a heatwave is declared 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.
In comparison, heat stress is a measure of more than just air temperature as it also takes into consideration humidity, wind speed and solar radiation. Heat stress can occur even without a heatwave.
To help members of the public make more informed decisions when going outdoors in the intense heat, NEA launched a national heat stress advisory in July 2023.
The advisory classifies heat stress levels as low, moderate or high, based on wet bulb globe temperature (WBGT) measurements.
A WBGT reading of 33 deg C and over signals high heat stress, and members of the public are urged to minimise outdoor activities and take more frequent breaks away from the sun, among other things.
The heat stress advisory aims to minimise the risk of heat-related illnesses such as heat cramps, heat exhaustion or, in severe cases, heat stroke, which can be fatal, NEA had said.
4. Is it sufficient to use only air temperature to measure heatwaves?
Internationally, most countries establish their heatwave definition using air temperature as the standard metric, and Singapore has done so as well, said the task force.
The forecasting of air temperature is well established, with weather models being able to provide reasonably reliable forecasts, it added.
"At the same time, we do recognise the importance of the other parameters, apart from air temperature, such as humidity, wind and solar radiation, in determining heat stress levels," said the task force.
The Government has developed advisories on heat stress management for the public and implemented sector-specific guidelines for different segments of our population based on the WBGT, the task force said, citing the Ministry of Manpower's (MOM) guidelines for outdoor workers.
These guidelines are applicable on a day-to-day basis and are especially important during periods of heatwave, when the risk of heat stress is increased. For example, MOM introduced enhanced measures last September to reduce heat stress risks for outdoor workers. Employers are required to implement heat stress measures based on WBGT bands.
Under the measures, employers have to, among other things, give workers adequate rest breaks under shade, and put them through acclimatisation programmes - for new workers and those returning from a leave period of more than a week.
5. What are some other measures under the national heatwave response plan?
The task force has come up with a suite of measures that will kick in when a heatwave is expected.
They span various sectors and also outline how vulnerable groups should protect themselves from the rising mercury.
For example, when the heat response plan is activated, cooling centres will be open to the public to seek respite.
The task force said the People's Association's air-conditioned community cooling centres at selected community centres and residents' networks located near Housing Board one- and two- room flats and rental units will be open to all members of the public seeking heat respite.
Up to eight air-conditioned sport halls may also be repurposed as heat relief centres for vulnerable groups in the community.
During this period, Singaporeans should minimise outdoor physical activities between 11am and 4pm due to higher heat stress levels during this period.
For vulnerable groups, more precautions are to be taken. For example, pre-schools are not to conduct outdoor activities between 11am and 4pm - usually a period of high heat stress - as the children enrolled in these centres are younger.
All schools should also implement dress-down attire and minimise outdoor activities during the same time period. Outdoor activities should also be modified or suspended according to the heat stress level.
The task force added that if the national posture is to adopt heightened measures, MOE will guide schools to go on either partial or full home-based learning so as not to disrupt students' learning.
