People in Singapore have been feeling the heat since long before climate change dominated discussions on rising temperatures around the world.
The reason? The urban heat island effect - a phenomenon where buildings, roads and vehicles release heat into the environment, especially at night. Studies show this has caused temperature differences of up to 7 deg C between urban and less built-up areas of Singapore.
And with global warming expected to nudge temperatures up by between 1.4 and 4.6 deg C by the end of the century, making the outdoor environment cooler should be a national priority, a team of scientists and policymakers said yesterday.
"The urban heat island effect will compound the warming force of climate change... All cities, not just Singapore, will face the twin effects of global warming and the urban heat island effect," said Urban Redevelopment Authority (URA) chairman Peter Ho.
He was speaking at the Cooling Singapore symposium held during the World Cities Summit conference at the Marina Bay Sands.
At the event, researchers from a Cooling Singapore project - a research initiative first launched last year - also referred to a "menu" of 86 possible measures across seven key areas they have come up with to help make Singapore's outdoor environment cooler. The seven are greenery, urban geometry, water features, material and surfaces, shading, transport and energy.
Far from the caricature of a giant air-conditioned dome covering Singapore, the measures aim to make the Republic cooler in other ways, such as through design and the use of innovative materials. For example, varying building heights could improve wind flow, while using light-coloured or reflective surfaces on pavements and building facades could lower absorption of heat energy from the sun.
Such measures are already in place in some areas of Singapore. For example, the Marina Bay Financial Centre has structures of varying heights to capture wind, said Assistant Professor Winston Chow of the National University of Singapore's geography department, who is a principal investigator of the project. But he cautioned that the measures are not one-size-fits-all, and had to be contextualised to specific sites and conditions.
On the importance of contextualisation, Cooling Singapore lead principal investigator Gerhard Schmitt said each site had features that could influence ambient temperature. In the Central Business District, for example, a street could be surrounded by glass-covered building facades, resulting in lower ambient temperatures, compared with a street in Punggol surrounded by concrete structures.
"This is why the Cooling Singapore project also involves modelling and field measurements at specific sites," said Professor Schmitt, who is from research institute Singapore-ETH Centre. It was set up by the Swiss Federal Institute of Technology in Zurich in partnership with the National Research Foundation under its Create programme.
Moreover, such studies are needed to find out whether these measures, if taken together, can magnify the cooling effect or cancel each other out.
The Cooling Singapore project, led by the Singapore-ETH Centre and comprising academics from NUS, Singapore-MIT Alliance for Research and Technology and Tumcreate was launched last year. There is also a Cooling Singapore Taskforce comprising 14 other government agencies and research institutes, including the URA.
Scientists say the next step would be the creation of a road map of measures each government agency can take to lower outdoor temperatures.
Prof Chow said: "The urban heat island effect has been undervalued previously, and this project aims to bring it to the forefront. There are many benefits to managing it properly, whether it be in the form of cost savings from using less energy or indirect benefits of having more greenery in the city."