Measures to Mitigate Rising Temperatures and Create More Conducive Working and Living Environments

Dr Tan Wu Meng asked the Minister for National Development (a) what studies have been conducted on the ambient interior temperature of HDB flats across different times of the day and weather conditions; (b) whether these temperatures are expected to increase, given climate change trends and, if so, by how much; and (c) whether such trends are considered when setting out design specifications for newer HDB projects.

Let me elaborate on the specific measures we have put in place to cool the environment and address the urban heat island, or UHI, effect in our neighbourhoods, community spaces and industrial estates.

Prof Koh Lian Pin asked about the progress and impact of our initiatives to reduce ambient temperatures, such as the introduction of greenery on the top decks of our multi-storey carparks, the use of cool paint on HDB blocks, and the planting of trees in our industrial estates. He also asked whether we select specific tree species or vegetation to provide the most optimal cooling benefits. Dr Tan Wu Meng asked if studies have been conducted on ambient interior temperatures of HDB flats across different times of the day and weather conditions, and if we consider temperature trends in designing new HDB projects.

As Minister Grace Fu earlier highlighted, the Government adopts a science-based and proactive approach to various aspects of climate adaptation, including the rise in temperatures. BCA requires buildings to be designed to limit heat gain from the exterior, which helps to improve thermal comfort for building occupants. BCA's Green Mark scheme also recognises buildings that implement UHI mitigation measures, such as applying cool paints and providing greenery. In the design of HDB projects, HDB currently deploys various strategies to optimise thermal comfort. For example, our HDB buildings are predominantly oriented in the North-South direction to reduce heat gain. For new towns and estates, HDB conducts environmental modelling to site new flats, design building facades and refine building layouts to harness existing wind corridors and optimise wind flow.

For existing towns, HDB is conducting a pilot study on cool paint which could absorb less heat and reduce the ambient temperature of HDB blocks. Past trials have shown a reduction of ambient temperatures by up to 2 degrees Celsius. The pilot is expected to be completed in 2024. Based on the study's outcomes, HDB will consider extending the use of cool paint to more estates. Under the HDB Green Towns Programme, which covers all existing HDB towns, HDB is introducing greenery to the top decks of selected multi-storey carparks (MSCPs) in the form of urban farms, community gardens, or rooftop greenery using the Prefabricated Extensive Green (PEG) Roof Tray System based on the suitability of the carparks. These efforts also aim to reduce ambient temperature.

We are also intensifying greenery in our industrial estates, which are amongst the hotter areas in Singapore. To date, nearly 90,000 trees have been planted in our industrial estates under the OneMillionTrees movement, with the help of our partners and the community. These trees are planted to resemble the look and feel of natural forests, to provide pedestrians with shade and respite from the heat. These efforts have helped to beautify and cool industrial estates, such as Jurong Island, Seletar Aerospace Park and Tuas Industrial Estate, to create greener and more conducive workplaces. We aim to increase the total number of trees across our industrial estates from 180,000 trees today, to about 260,000 trees by 2030.

Studies have shown that intensified tree planting in Singapore can reduce mid-day temperatures in the surrounding areas by up to 0.9 degrees Celsius. We will continue planting more trees across Singapore under the OneMillionTrees movement, to mitigate the effects of climate change and provide Singaporeans with a more liveable and sustainable environment. We are also working with Institutes of Higher Learning to examine the cooling effects of various tree typologies and planting configurations. We will also deploy an island-wide network of sensors to monitor the cooling effects of our tree planting efforts. The data collected will support microclimatic research in Singapore and help NParks develop better greening strategies to cool Singapore.

In summary, the Government takes a broad-based holistic approach that will help all segments of the population cope with rising temperatures. Dealing with the impacts of climate change requires collective action and community resilience. Together, we will ensure that as a nation, we can adapt, adjust and remain resilient in the face of climate change.

I thank the Minister and the Senior Minister of State for their answers. I have three supplementary questions. Mdm Deputy Speaker, as background, yesterday, in the US journal, Proceedings of the National Academy of Sciences (PNAS), a peer-reviewed report was published by the Cambridge Centre for the Study of Existential Risk. Entitled "Climate end game: exploring catastrophic climate change scenarios", it proposes serious consideration of worst-case scenarios in climate crisis. My three questions are as follows.

Firstly, the Minister mentioned that the temperature projections might reach peak daytime temperatures of 40 degrees Celsius in Singapore by the year 2040. Can I ask if this a median scenario or have worse, more severe scenarios been considered and are we getting ready for those as well?

Secondly, is the Government considering the possibility of low probability, high-impact situations? For example, if extreme climate situations affect energy resilience, and thereby, the ability of households in Singapore to maintain air-con across the island during a heat wave.

And thirdly, I am not sure if I had missed the answer, but has the Senior Minister of State from MND mentioned what is the data on the temperature of HDB dwellings across different times of the day, and in particular, whether HDB flats will continue to be safely habitable amidst very high temperatures, even in the absence of air-con?

Mdm Deputy Speaker, I would like to thank Member Dr Tan Wu Meng for his questions, in fact, I am very gratified to see that Members are truly interested in climate change and its impact on Singapore and Singaporeans.

It is the greatest challenge to mankind and we should really devote attention and resources to address this global challenge squarely.

In our projection, we look at three broad scenarios. One is the business-as-usual scenario; the other is a scenario where we are taking good steps to mitigate emissions; and the third is to assume a situation where fossil fuels continue to be harnessed for energy. This is not a scenario that is determined by Singapore only. This is actually adopted by IPCC, which assesses a collection of thousands of scientific journals and scientific research. It is, in a way, an aggregation of the global thought leadership on climate change issues.

So, within these three scenarios, the peak 40 degrees Celsius forms one of the data points. But, obviously, we are looking at the three scenarios squarely and looking at how they would impact Singapore specifically. Because we are quite different from the Northern or Southern hemispheres – we have tropical weather, we are an island, we are not part of large continental masses. So, we do have our own climatic patterns that require careful local study. And that, in fact, is what we will be doing over the next few decades.

Indeed, I think Dr Tan Wu Meng is very wise to point out that there are low probability but high-impact events. We are constantly in discussions with the scientists. We just hosted the World Climate Research Programme Sea Level Conference in Singapore and had the chance to speak to many world-class climate scientists, which informs our planning.

While our long-term planning does not have these specific impact events in mind at this point, we are constantly looking for inputs and they will always shape our planning parameters. I will leave the third question to Senior Minister of State Tan Kiat How.

Mdm Deputy Speaker, I thank the Member Dr Tan Wu Meng for his question. At the heart of it, I think he is asking whether HDB plans for the thermal comfort of residents as a priority. I would like to assure Dr Tan that it is indeed so.

I mentioned in my earlier remarks that we look at the environmental modelling and wind flow, and we consider how the occupants of an HDB building can be comfortable, even during the day. We do not take the assumption that everybody switches on their air-conditioning.

And perhaps, an additional assurance to Dr Tan, that the HDB Green Towns Programme looks at a 10-year plan to make HDB towns more sustainable and liveable.

To his question about the energy consumption of HDB towns, it is something that we are concerned about. The HDB Green Towns Programme, which I mentioned, focuses on reducing energy consumption, recycling rainwater and cooling HDB towns. We aim to reduce the energy consumption in HDB towns by 15% from 2020's level, by 2030.

I would like to add on about thermal comfort. We look at passive strategies in the design of these buildings to optimise thermal comfort. Like I mentioned, we do not make the assumption that everybody switches on the air-conditioning. Thus far, wind flow is the main focus of HDB's effort in thermal comfort design. For new towns and estates, HDB conducts environmental modelling to site the new flats – I mentioned about the North-South facing earlier – but also, we look at the building design facades and in refining the building layouts, the room layouts, to maximise the wind corridors and optimise wind flow. A specific example includes orienting the HDB buildings in the North-South direction and requiring 45% to 60% green cover in new estates to ensure sufficient greenery to create a comfortable living environment for all Singaporeans.

Thank you, Mdm Deputy Speaker. This is in relation to some of the responses that Senior Minister of State Tan Kiat How has provided. This is a follow-up supplementary question on that.

I understand that in relation to the HDB Green Towns Programme, there will be more features that will be introduced by HDB. In this regard, I wish to make a proposal to HDB for consideration. For many of our existing HDB flats, we incorporate full glass windows that admit a considerable amount of heat during the late afternoon. So, my question is whether HDB can consider installing the low-heat transfer, double-glazed windows for BTOs moving forward, and also, as part of the features for existing HDB flats as part of the Home Improvement Programme (HIP)?

This will really help, because, apart from new methods that HDB is introducing, for example, cool painting, I believe that there is a dire need for us to consider, to explore other suitable greener alternatives that help cool down HDB flats, especially since more Singaporeans are now adopting flexible working arrangements and working from home.

I thank the Member Ms Hany Soh for her questions. I fully agree that windows are a very important part of the HDB living residential unit. As earlier mentioned, the flow of the wind and the natural ventilation are important strategies to keep the thermal temperature within units comfortable for the residents.

We will certainly look into the suggestions by Ms Hany Soh – about the use of double-glazed windows to minimise heat transfers. These are some of the areas that we are always studying with the research institutes, as well as our partners.

Perhaps, just to give a little bit more assurance to Ms Hany Soh, I will explain how we design windows. Today, windows are provided with canopies, which provide sun shading and shielding from rain. The windows are also designed with larger, openable panels, as well as smaller top hung windows, such that the large panels are closed during heavy rain, while the top hung windows can still be opened slightly to provide natural ventilation within the flat.

So, windows and how they are designed and the ventilation flows arising from that, are important design considerations for HDB.

Thank you, Mdm Deputy Speaker. I refer to the urban heat vulnerability analysis report, published in June 2020 by Cooling Singapore, which is quite a detailed first stage analysis, I understand. A report where they stated that further research is being done, especially in relation to the regional effect of heat.

This report states that climate change intensifies not only the urban heat island effect, but also causes health, social and economic challenges.

So, I would like to know, in terms of these cross-Ministerial, whole-of-Government issues, which Ministry or agency is responsible for leading the cross-agency plans and coordination to address these challenges?

One of my supplementary questions would be what are the efforts to raise awareness of heat injuries in groups, such as the elderly, parents of young children and people who work outdoors more, because obviously these groups are more exposed to the heat, which will only intensify as the years go on?

Again, I refer to India's Heat Action Plan, for example, which identifies high-risk populations and groups, and increases outreach and communications about the dangers of increased heat to these groups.

So, I am just wondering, maybe this is something that MSE would be working together with MOH on? I would like to ask whether the Ministers are able to share more information about this at this stage.

Finally, I have one question for MND, in particular. I noticed that in the report that I quoted earlier from, the urban heat vulnerability analysis report, there was a segment where there was some analysis and studies done on access to cooler indoor spaces —

Yes, I am referring to the indoor spaces, during particularly bad heat waves. I am just wondering whether this information is going to be or has already been integrated into town planning, and whether residents have adequate access to refuge in the day, during exceptional heat waves? Whether or not, this is something that MND is actually looking into?

Mdm Deputy Speaker, I would like to thank the Member for the supplementary questions. Indeed, I think it is important for us to think about challenges very holistically. And that is really the genesis of the Singapore Green Plan, which is to bring multi-agencies' work together and to integrate our plans, so that we are clear about the trajectory and pathway that we are heading towards.

Similarly, when we come to issues, such as how hotter temperatures are going to affect human health, there are also inter-agency work groups to study that, whether it is MOH with MSE on heat stress affecting human health, or MOH, MOM and the Workplace Safety and Health Council to study the impact of heat on our work practices.

So, that will continue to be the way the Government handles climate change. Each of the Ministries will have its own policy portfolio and they will continue to refine and review their policies going forward, with information that is coming in from the various studies that we are doing – whether it is with V3 or other studies, such as the one the Member quoted. It is really part of our research effort to understand various impacts of climate change on Singapore better.

And we also have the Inter-Ministerial Committee that is chaired by Senior Minister Teo Chee Hean that will bring the relevant Ministries together. As and when we are informed with new inputs, we will review the relevant policies and we will get the relevant Ministries together to study some of these cross-Ministry problems.

Mdm Deputy Speaker, the short answer to the Member Ms He Ting Ru's question is yes. Mitigating UHI effect, both in our residential areas, community spaces and industrial areas, is something that the MND family is looking at very carefully and part of our design considerations.

And to add on to a point – Ms He Ting Ru mentioned the research of the Cooling Singapore project. Just to share with Ms He that it is not just about the covered spaces, but we are also looking at the outdoor thermal comfort and outdoor shading for Singaporeans as they go about their different activities outdoors.

For example, NParks is collaborating with researchers from the NRF-funded project, "Cooling Singapore 2.0", to study the impact of greenery on urban heat mitigation, specifically on tree shapes, planting configurations and size of green spaces.

I am actually very heartened that the recent modelling study of trees in HDB residential precincts preliminarily shows that trees with large canopies, such as umbrella- and oblong-shaped trees, are more effective in improving outdoor thermal comfort. In addition, increasing the tree planting densities, which we are doing under our OneMillionTrees movement, will lead to further improvements in outdoor thermal comfort.

And studies by other researchers have also shown that our structured multi-tiered planting – managed trees over shrubs, multi-layers of canopy – can reduce mid-day temperatures by up to 0.9 degrees Celsius.

So, holistically, we are not just looking at the design of indoor spaces, community spaces, facades of buildings, windows, ventilation, wind flow, but we are also looking at using greenery, which are nature-based solutions, to achieve outdoor and indoor cooling.