he adverse impact of extreme weather caused by climate change affects us all whether we live in the Arctic, Africa or Asia. While Singapore may be spared from the worst effects, it is still feeling the heat from climate change. Not only are annual temperatures setting new records, Singapore faces an existential threat from rising sea levels caused in part by melting ice caps and glaciers. Much of the country lies only 15 metres above the mean sea level, with about 30% less than 5 metres.
Speaking to Parliament during Budget 2019, Finance Minister Heng Swee Kiat said, “Climate change and rising sea levels threaten our very existence. As a low-lying nation, there is nowhere to hide when sea levels rise. Other small island nations like the Maldives are already facing risk of flooding, with severe implications. To protect ourselves against climate change and rising sea levels, we will have to invest more.”
Already low-lying roads near coastal areas are being elevated. For critical infrastructure such as the planned Changi Airport Terminal 5, it will be built 5.5 metres above mean sea level. Singapore is also piloting the use of polders and dikes on Pulau Tekong to help us learn how to deal with rising sea levels.
Although it is difficult to project spending needs way into the future, Mr Heng announced that the government will have to invest more to prepare Singapore for climate change. “We will continue to do our best to look forward, develop fiscal plans well in advance, and put in place the right approach to finance such long-lived major infrastructure,” he said. Together with the existing infrastructure needs, this will increase the total spending on infrastructure significantly.
Mitigating Urban Heat Intensity
The built environment sector has come under increasing scrutiny. As buildings account for about 40% of the world’s energy consumption, how can we design, construct and maintain buildings that are less energy-dependent, and less environmentally damaging?
Urban Heat Intensity (UHI) is a phenomenon common in cities. Urban areas are warmer than surrounding rural areas because of the heat generated by buildings, vehicles and trains. For Singapore, one of the densest cities in the world, built-up areas in the city can be up to 7°C hotter than the outskirts.
A research initiative has been launched to explore different means to mitigate the UHI effect, from greenery to urban geometry. By varying building heights for instance, wind flow can be improved. The use of light-coloured or reflective surfaces on pavements and building facades can lower absorption of heat energy from the sun.
The Cooling Singapore project is led by research institute Singapore-ETH Centre, which was established by the Swiss Federal Institute of Technology in Zurich in partnership with the National Research Foundation (NRF) under its Create programme. It comprises academics from the National University of Singapore, Singapore-MIT Alliance for Research and Technology and TUM CREATE (Technical University of Munich). In addition, there is also a Cooling Singapore Taskforce comprising 14 other government agencies and research institute, including the Urban Redevelopment Authority (URA) and the Singapore University of Technology and Design.
Together with the URA and the HDB, researchers have begun modelling studies to see how different mitigation measures can be applied. It has been found that more reflective roofs can achieve up to a 1.29°C reduction in temperature, new developments can change air patterns and increase thermal stress, depending on weather conditions, and void decks at public housing blocks can have a positive impact. More vegetation may seem to cool the place but it is not always the case, as trees can reduce wind speed and increase humidity.
The project has come up with a menu of 86 possible measures spanning seven key areas - greenery, urban geometry, water features, material and surfaces, shading, transport and energy - to help make Singapore’s outdoor environment cooler.
Principal investigator of the Cooling Singapore project Assistant Professor Winston 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 is in the form of cost savings from using less energy; or indirect benefits of having more greenery in the city.”
Researching New Materials
New materials are being explored in the drive to go green. At the National University of Singapore (NUS), researchers from the School of Design and Environment have found a way to use wood waste to strengthen building materials. The new method combines cement with biochar, a material produced when heat is used to decompose sawdust, to increase concrete’s strength and impermeability.
Lead researcher Dr Kua Harn Wei said that water is usually added to powdered concrete to create a wet mix in a process called hydration. But as water evaporates during the process, the mix is weakened. However, when biochar is added, the mix is better at retaining water, which in turn produces stronger concrete.
Biochar in powdered form also plugs gaps that exist within the concrete mix, reducing water seepage through cracks that may form when it is set. The researchers found that adding biochar strengthened the concrete mix by 20% and its impermeability by 50%.
Using biochar is also environmentally friendly as tonnes of wood waste are produced in Singapore, mainly from furniture factories. In the past, the wood waste would be incinerated or disposed of.
The NUS team is undertaking further research on cement composites to serve wider applications.
Engineering Eco-Friendly Solutions
A new S$61-million research laboratory has been set up to look into ways to optimise land usage, come up with eco-friendly solutions for buildings and improve productivity in the built environment sector. Launched in August 2018 by the Nanyang Technological University (NTU), Surbana Jurong (SJ) and NRF, the SJ-NTU Corporate Lab is starting with 11 projects focused on three themes - digitalisation, sustainability and future-proofing the built environment industry. Among them are chilled ceiling panels suited to the tropics, which can reduce the amount of energy needed to cool a room while removing impurities; and better ways to store liquefied natural gas - the main energy source here - in industrial and urban areas so that the space above ground can be freed up for other uses.
Successful solutions developed by the laboratory will be rolled out in projects undertaken by SJ, a government-owned consultancy company focusing on infrastructure and urban development, and eventually sold to companies and governments, especially those in the tropics.
Spurring Move to Greener Buildings
Standards for the Green Mark Scheme, launched in 2005 by the BCA to evaluate and set benchmarks for environmental sustainability in buildings, have been progressively raised. Under the latest rating, Green Mark for Super Low Energy, office buildings cannot use more than 100 kilowatt hour (kwh) per square metre a year. This is at least 60% more energy efficient compared with 2005 building codes.
“By setting such new performance benchmarks, Singapore can play an important role in mitigating climate change,” said BCA’s chief executive Hugh Lim.
More than 10 organisations, including the Defence Science and Technology Agency, Singapore Management University and City Developments have pledged to achieve at least one super low-energy project in the next five years.
The BCA is working with property developer Keppel Land to convert Keppel Bay Tower, a Green Mark Platinum building, into a super low-energy building. Five technologies to be tested in the 18-storey building include a smart lighting system, a fresh air intake system that regulates the flow of outside air into the tower and a cooling tower system that regulates the structure’s temperature without the need for chemical water treatment.
If successful, the building’s annual energy consumption is expected to lessen by 20% to 115 kwh per square metre a year, saving the company an estimated S$250,000 annually.