Living on “Aircon”

Shreya Upadhyaya
7 days ago
6 min read

Singapore’s search for cool in the midst of climate change and urban heat

The other day, I spent a few hours at Punggol Digital District, touted as a cornerstone of urban sustainability in Singapore. It is carefully planned and equipped with district cooling systems and green building features, that are designed to maximise passive ventilation, reduce the demand for electricity use for air-conditioning, and keep outdoor spaces relatively comfortable throughout the day. This is the blueprint for the future of Singapore. Yet, as I walked under one of its many shaded walkways, I overheard a woman exclaim: “I need aircon!”.

She’s not the only one. In recent years, Singapore has experienced a slow but steady rise in temperatures. Since the 1980s, the annual mean temperature has increased by 0.24°C per decade. This has meant that increasingly, it feels impossible to leave the artificial cool of air-conditioned interiors, especially in the middle of the day. Understanding the underlying factors of the intolerable heat necessitates looking at the situation from both a local and global context.

Cascading Factors of Urban Heat

Global climate change has raised baseline temperatures, making “normal” days warmer than they used to be. Periodic El Niño events then add intense heat on top of this already elevated baseline. It’s expected that this will continue to strengthen in the latter half of 2026. In a humid tropical city like Singapore, this translates modest temperature increases into much higher apparent temperatures (the “RealFeel” indicator you see on the weather app of your choice).

Singapore’s heat stress is also increasingly described using Wet Bulb Globe Temperature measures, which combine temperature, humidity, wind, and solar radiation to accurately determine safe activity levels at various points of the day. This serves as a reminder that in Singapore, it is not just how hot the air is, but how saturated and still it feels on the skin.

However, the heat in Singapore is not just about the global climate system; it is also about how the city is built and inhabited. Despite the moniker of “Garden City”, rapid urbanisation has replaced densely vegetated areas with materials like concrete and asphalt. These materials absorb heat during the day and release them during the night. This results in the urban heat island effect, where dense urban districts are several degrees warmer than nearby rural areas. This has resulted in “hotspots” in Singapore in locations like Punggol, Sengkang, Marine Parade, and Jurong East.

At the same time, despite looking green from the outside, much of the greenery that lines roads and surrounds buildings in Singapore is ornamental or non‑native. Research on urban trees in Singapore has shown that species choice matters: some trees deliver stronger evapotranspirative cooling than others, while certain plantings can even trap heat or limit wind flow if poorly selected. Therefore, despite achieving greenery, it is becoming apparent that planting the right trees is far more important than just planting more trees.

Air-Conditioned Nation

Singapore’s founding father, Lee Kuan Yew, famously attributed the country’s success to air-conditioner usage. Several decades on from his declaration, the humble air conditioner continues to play a pivotal role in the Singaporean’s life, shaping daily commutes, working environments, and activity preferences (mall trip, anyone?). With rising temperatures, cool air is now an expectation, not a luxury.

This dependence has consequences. As temperatures rise, so does demand for cooling, driving up electricity use and, unless the power system is fully decarbonised, feeding back into higher emissions and further warming. The hotter it gets, the more we cool, and the more we cool, the more we risk heating the planet.

It is also entangled with inequality. Studies of urban heat vulnerability in Singapore and elsewhere show that risk clusters in areas with higher densities of older adults, outdoor workers, and communities with limited social support. These are the people least able to afford rising cooling costs, least likely to live in optimally insulated housing, and most exposed to the sun on construction sites, roads, or delivery routes. For them, urban heat is an everyday occupational hazard.

Recent work under the HEATS project, for instance, has shown that construction workers living in non‑air‑conditioned dormitories lose around 10 minutes of sleep for every 1°C rise in nighttime temperature, illustrating how heat exposure at work spills over into poorer rest and higher risks of illness and accidents.

This is a kind of double exposure: vulnerable groups are simultaneously exposed to rising background temperatures and to socio‑economic constraints that limit their ability to adapt. In such a context, the question “why is it so hot in Singapore?” cannot be answered without asking “hot for whom?”

Of Cooling Paints and Digital Twins

So what is Singapore doing about this? On paper, quite a lot. Technology-heavy solutions have been a key pillar of the country’s approach, with the creation of a Digital Twin allowing policymakers to determine the effectiveness of various urban heat mitigation strategies. Innovative solutions like cool paints promise a few degrees of relief on sun‑baked façades. Meanwhile, sophisticated district cooling systems help cool places like Tampines town centre. It is an impressive suite of innovations, using technology, data and engineering to manage the symptoms of climate change at the urban scale.

However, technocratic solutions may be limited in impact or effectiveness. Emerging trials in schools and other sites suggest that cool paints are not a silver bullet. Depending on where and how they are applied, highly reflective coatings can, in some cases, increase radiant heat for occupants by bouncing sunlight into courtyards or play areas, underscoring the need for careful siting and design.

Such technology reliant solutions should only be one facet of the solutions used. Urban greening, from roadside shade trees to park connectors, has long been a quieter pillar of Singapore’s heat strategy. Emerging ideas like microforests (small, dense patches of native vegetation) show that even tiny parcels of land can provide meaningful cooling, alongside other benefits like biodiversity and improved mental health. Unlike smart coatings or high‑tech chillers, trees and microforests sequester carbon, cool surfaces through shade, and require no dashboards to perform.

One recent example is the CDL MicroForest outside City Square Mall, where monitoring has found temperatures up to 5°C cooler inside the tiny forest compared with surrounding paved areas, alongside early signs of thriving native wildlife. These kinds of experiments suggest that Singapore should aspire to be a “city in forest” or even a “city in jungle”, rather than merely a “city in nature” where greenery is thin, decorative, and thermally under‑performing.

Mitigation, not just Adaptation

There is a risk that, in the rush to become “heat resilient”, Singapore focuses too narrowly on adaptation (keeping bodies and buildings cool) and not enough on mitigation: cutting the emissions and unsustainable urban forms that drive the heat in the first place. National climate plans and regional cooperation under the Paris Agreement signal commitment to net‑zero emissions by mid‑century, but the pace and scope of change remain constrained by many factors.

The Singapore Green Building Masterplan, for instance, sets ambitious “80‑80‑80” targets to green 80% of buildings, push most new developments towards super low energy standards, and improve the efficiency of best‑in‑class green buildings by 80%. Despite that, many buildings from the late 1980s and before still face structural and financial barriers to deep retrofitting, making energy‑efficiency upgrades and cooling improvements in older residences and industrial facilities a critical challenge.

Newer “green” precincts like Punggol Digital District and other super low energy estates offer promising blueprints for future urban design, but meaningful progress will also depend on retrofitting older buildings and industrial sites to cut waste heat and improve thermal comfort. In a land‑scarce city where redevelopment often means demolishing and rebuilding, sometimes at the expense of mature trees or forest patches, heat resilience will increasingly hinge on how Singapore balances growth with the protection and regeneration of its most effective natural cooling assets.

If Singapore is to avoid a future where stepping outside always feels like stepping into an oven, it will need to cool not just its buildings, but its emissions. That means relying on nature‑based solutions alongside digital ones, redesigning streets and housing estates for shade and ventilation, and ensuring that the benefits of both trees and technology reach those who face the brunt of the heat.

As studies like Project HEATS show, simple and affordable measures in worker dormitories, from better ventilation to targeted fan use, can already make a tangible difference to sleep and safety, reminding us that just transitions in a hotter world start in the everyday spaces where people live and rest. The woman at Punggol Digital District may always “need aircon” on some days, but the goal of a truly sustainable city should be to make it possible, and safe, for her to choose otherwise.

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