How Singapore became obsessed by shade

The sweltering island nation has long prioritised adding greenery and shade at every corner. Could other cities do the same?

Heat is humanity’s most lethal climate threat, taking more lives every year than floods, hurricanes and wildfires combined. And the risk is greatest in cities, which are warming twice as fast as the rest of the planet because of the urban heat island effect.

As dangerous temperatures become more common, the leaders of cities around the globe, from Paris to Phoenix, are strategically planning to throw more shade.

But it’s the sweltering island nation of Singapore which may well already have the best shade infrastructure of any city on Earth. People here have long had their own tricks to deal with the torrential rain and sticky heat.

Chief among them might be the covered sidewalks. The origin of this public shade is unclear. Although these “five-foot ways“ which tunnel through the ground floors of arcaded shops and houses, resemble the porticoes of Bologna, they may be native to Southeast Asia. Stamford Raffles, the British colonial official considered to have founded Singapore in the early 19th Century, wrote them into the first town plan in 1822.

Raffles mandated clear, continuous and covered passages on both sides of every street to ensure efficient transit in inclement weather. Over time, his “verandah-ways” fell out of favour. They were revived in modern form by Lee Kuan Yew, the powerful prime minister who guided Singapore to independence in the 1960s.

Lee was something of a micromanager and had a particular interest in climate and comfort. He believed that humidity was stifling the country’s economic productivity. Indoors, he transformed Singapore into what journalist Cherian George called the “air-conditioned nation”. Outdoors, he was fanatic about shade. Lee was known to lecture subordinates about the poor design of footpaths and promenades, sometimes kneeling on the burning hot ground to prove a point.

In the 1960s and 1970s, as Lee’s authoritarian government erected towering public housing estates, architects kept the ground floors of every building open to the air, preserving the areas as communal “void decks” where residents could gather to catch a breeze. In the late 1980s and 1990s, Singapore’s housing and transportation agencies directed the construction of freestanding metal canopies over the sidewalks to ensure dry paths to the nearest bus or train.

Today, the authorities claim to have erected around 200km (124 miles) of covered walkways. Try to imagine if New York’s ubiquitous construction scaffolds were permanent sidewalk architecture and you might have some idea of what the immensely unattractive though functional achievement looks like.

In the US, real estate developers are required to set their buildings back from the street to let in more light, but in Singapore, they must contribute to the shade network by carving 8-12ft (2.4-3.7m) of pedestrian overhangs out of the ground floors of their buildings. Research suggests the canopies have an effect similar to that of a clean and well-designed bus shelter. Just as a shelter can make a wait for the bus go by faster, so too do Singaporeans report that a stroll under the walkways feels 14% shorter than a stroll under the sun.

“You’re in a tropical region where it’s always super hot, and always very humid,” says Yun Hye Hwang, a landscape architect and professor at the National University of Singapore. With daily high temperatures hovering around 31-33C (88-91F) year round, “we always need shade,” she adds.

When it comes to shade, almost everyone would prefer the leaves of a luscious canopy to a clunky aluminium roof, but trees can’t always be the answer, says Lea Ruefenacht, a former researcher with Cooling Singapore, a government-affiliated urban heat initiative. But she notes that trees create cooling through shade and by releasing water into the air: in humid Singapore, more moisture can add to the misery.

For comfort, Ruefenacht recommends a balance of both green and grey shade. In Singapore, the densest grey shade is found in the concrete understory of the skyscraper forest downtown. Real estate developers are required to furnish what the authorities consider “sufficient” shade on outdoor plazas, cooling at least 50% of seating areas between 9:00 and 16:00. The shade can come from any number of sources – trees, umbrellas, awnings – but in their design circulars, the authorities demonstrate that it can also be afforded by a nearby tower’s knifing shadow.

This approach can be contrasted to that of New York City, where building shadows on outdoor spaces are discouraged, and the mere threat of their existence can scuttle a new development. In this cooler climate, developers are instructed to site their plazas on sun-facing south sides, to create winter warmth. (In fact, the plazas are not allowed to face north.)

Singapore has a different priority. Ideally, developers locate plazas on the east side of their buildings, so they can be cooled by afternoon shade. It is the rare place where urban shadows are encouraged as a public benefit.

“In the tropical regions of the world, part of the problem has always been that settlements inherit building codes from the temperate regions, and they don’t necessarily have the means to review it and ask, ‘does this work for us?'” says Kelvin Ang, the conservation director at Singapore’s Urban Redevelopment Authority. “In Singapore, somehow there was a lot of awareness that building codes and planning codes had to encourage shade, because of the intensity of the sun.”

Planners believe that if a public space is unshaded, no one will use it. Despite the potential effects on humidity, Prime Minister Lee demanded trees everywhere, believing that a “clean and green” Singapore would be attractive to foreign investors. Under his command, a newly formed parks and trees unit spruced up the major boulevards, embowering them under the broad canopies of Angsanas, rain trees, mahoganies and acacias. “Flowers are okay,” Lee reportedly told the department head, “but give me shade first”.

In the 1970s, as he implemented congestion pricing and other schemes to push Singaporeans out of their cars and onto public transit, Lee turned his attention to the sidewalks, crosswalks and bus stops where a pounding Sun could have repelled potential new riders.

In Los Angeles, trees are the last piece of the street-design puzzle, blasted into concrete pits and stuffed haphazardly into sidewalks after every vault and metre has been trenched, every curb has been built, every gutter cut, and every driveway poured.

In Singapore, however, Lee ordered his land-use planners to consider them from the beginning. The overhead power lines that disfigure LA’s sidewalks and make trees small and shrubby are rare. Most utilities are laid underground in vaults that run alongside the street trees and their roots. The green infrastructure is plotted by urban planners, engineered by public works agencies, and managed by a parks board whose budget increased tenfold under Lee’s leadership.

The funding and coordination have proven to be the difference between a thriving urban forest and a bunch of sad city trees. Besides the roads, Lee’s urban planners mandated greenery in private developments, regenerating a new garden city to compensate for the natural rainforest that was all but gone.

The Singaporean government had a lot of leverage. Through strong eminent-domain rules, it owned about 90% of the land, and building inspectors wouldn’t clear a building for occupancy until they saw trees on the ground. Singapore’s extensive public housing estates also came with grassy lawns, leafy courtyards and tree-lined paths that connected to parks and nature reserves. As a result, trees are just about everywhere in Singapore, in rich and poor neighbourhoods alike.

“We did not differentiate between middle-class and working-class areas,” Lee wrote in his memoirs, claiming it would have been “politically disastrous” for the People’s Action Party. It makes Singapore distinct from American cities, where shade is a reliable indicator of economic inequality.

Thanks to Lee’s smart planning policies, including developing thousands of acres of local parks and hugely ambitious land reclamation efforts, Singapore managed to do something remarkable: it became simultaneously denser and greener. The authorities claim the urban forest grew from 158,600 trees in 1974 to 1.4 million in 2014, even as the city added three million more people. Today, almost half the island is covered in grasses, shrubs and broad-canopied trees, throwing cold water on the idea that cities can’t spare room for nature as they grow.

“It’s the biophysical environment that’s a differentiating factor,” says Daniel Burcham, a former researcher at the parks board, when I ask him to explain Singapore’s success. “It’s just easy to grow trees when it’s summer every single day and you have over 2m [7ft] of rain every year.”

But without political consensus, he adds, there would not have been room spared for those trees to grow. “This was a goal that they [Lee’s government] were going to pursue, and it was a vision that they were all united around achieving.”

Burcham now teaches arboriculture – the cultivation of trees and forests – at Colorado State University in Fort Collins, a semi-arid city where political leaders have a few years in office, not decades. “Some would characterise Lee Kuan Yew as a strongman, or semi-authoritarian figure, and to some extent, that’s very true,” says Burcham. “But this is one good thing that came from that system. He set out this goal and provided material resources and provided political support for people to achieve it.”

But while it would require coherence across administrations, there’s no reason in principle why democratically elected governments in tropical cities like Miami or Honolulu could not also sustain such a project.

So does all this shade protect Singaporeans? In the afternoon, the streets of Singapore’s business district, plunged in the shadows of skyscrapers, are the coolest in the city. The effect ends when the sun goes down, and the buildings release the solar radiation they absorbed. At night, the green grounds of a public housing estate may offer the most relief, as the air is 1-2C (2-4F) cooler than the drafts whistling through a bustling commercial strip.

The well-established epidemiological link between air temperature and heat illness would indicate that these shadiest neighbourhoods are indeed Singapore’s safest from heat. Shade infrastructure like trees and buildings won’t be enough to overcome all the warming effects of climate change, but it will make a difference.

It’s unlikely that local American governments can be as effective as Singapore’s, an autocratic nation-state long ruled by a strongman with a personal interest in shade. Nor are most US cities fortunate enough to have Singapore’s ideal climate for growing trees.

Nevertheless, Singapore shows what can be done with intentional government planning of shade. A cooler city for everyone is within reach. Let’s not pretend it’s impossible.