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The Unwalkable City

Published onOct 26, 2023
The Unwalkable City

What are the roots that clutch, what branches grow
Out of this stony rubbish? Son of man,
You cannot say, or guess, for you know only
A heap of broken images, where the sun beats,
And the dead tree gives no shelter, the cricket no relief . . .

— T. S. Eliot, “The Waste Land”

Sri Lanka is an island, 7.8731° N, 80.7718° E—that is to say, just below India, just above the equator. There are mountains, rainforests, beaches, ancient ruins, and—before we turn into a travel brochure—enough problems to last several lifetimes.

One of these problems is Colombo.

On the surface, Colombo is a good pitch. It’s a small city, roughly 38 square kilometers. It comes with a beach and a port. It has the most wealth and best infrastructure in the country. The weather is warm all year round, the food ranges between dirt cheap and pretentiously overpriced, and … you’re now picturing a sort of semi-idyllic tropical paradise where business deals are struck in a verandah overlooking the sea.

To those more familiar with it, Colombo is a baking patch of asphalt and concrete, staring out with drying eyes at an indifferent sea. It’s a tropical paradise to those who can afford to live in hotels, but for the majority of its residents it is exhausting. To walk or cycle anywhere in Colombo, even up the lane, is to slowly succumb to a wet, sickly heat, to arrive dripping in your own sweat.

There is a peculiar humiliation in this heat. The cold you can button up against; this heat makes savages of us all.

Perhaps for this reason, walking anywhere is an activity reserved mostly for the poor. Those who can afford it shelter in private transport; those who can really afford it spend half their lives moving from one air-conditioned environment to the other.

I learned this firsthand when, two years ago, I moved from a fairly green suburb to the heart of Mount Lavinia, a dense seaside suburb into which Colombo spills. My logic was simple: I’d spent years locked away in my own rooms, staring at a computer screen, writing furiously. I needed to get out more, and the city beckoned. The beach was within walking distance, I had friends around, and Mount Lavinia’s lively streets offered much more than the small store to which I made my daily pilgrimage for cigarettes.

What happened was that I became even more shut-in. It was too damn hot to walk outside in the day; the beach, so close to my door, became a distant memory. Crossing the road felt like being a cut-rate vampire, cursing a sun that beat down on me like a crucifix.

To my surprise, nights were no different. Venturing out, even at midnight, felt like being hit by a wall of damp, rolling heat—this time from below and around me. As the year heated up, my bedroom began to feel like a microwave.

I initially discounted this as an isolated phenomenon; maybe it was just my neighborhood. After all, the road I live on is a smattering of flats (built as cheaply as possible) and an upwardly mobile waththa (a Sri Lankanism for a mishmash of tiny dwellings, just a few steps above a slum). I live in a haphazard maze of sorts, the kind where cooling breezes go to die.

And yet, as I made my way around the city in all kinds of weather—riots and protests included—I began to recognize that Colombo was suspiciously hot. Too hot for a beach town.

But here’s where things get odd. People that I’ve spoken to over the past few months—particularly those in their 60s and 70s—recall a Colombo where they comfortably went for long walks and bicycle rides, a green city where the noise and bustle of the harbour gave way to cool glades and green paths.1 On a much shorter time span, I had been coming to Colombo on a daily basis at least since 2010—first for school, then for work—and once-walkable areas of the city had become scorching, difficult lands to traverse.

But you know what they say: anecdotal evidence is only evidence of an anecdote. Were these recollections true, or was it simply the rose-tinted lenses of nostalgia? And why do other coastal cities of Sri Lanka seem so much more comfortable than Colombo?

When I spoke about this to Nisal Periyapperuma, my good friend and cofounder of Watchdog (the open-source research collective that we run), he hit upon a simple but effective test. Nisal purchased a bunch of infrared thermometers and, with our colleagues Sathyajit Loganathan and Ishan Marikar, we walked across a widely used section of the city in September, between 2 and 3 PM. As we walked, we logged the surface temperature, conditions (whether it was sunny or shaded), and the GPS coordinates.

This (admittedly low-budget and unsystematic) test gave us 158 observations. After a little bit of averaging, here’s how they look when mapped.

Digital image of an overhead map of roads in Colombo, Sri Lanka. The map's background is black, with roads in light blue. A bar graph sprouts from the roads, denoting temperature readings, in shades of beige, yellow, orange, and red.

Image by Yudhanjaya Wijeratne.

The zone with highest surface temperature, on average, read at 54 degrees Celsius: 129.2 degrees Fahrenheit.

Simultaneously, I began investigating the air. In his much-discussed 2020 novel The Ministry for the Future, Kim Stanley Robinson popularized the idea of the wet-bulb temperature. The concept originated when the U.S. military tried to understand outbreaks of heat-related illnesses,2 and made its way to climate science in due course. In a nutshell, wet-bulb temperature is the lowest temperature to which air can be cooled by the evaporation of water.

This might be odd to wrap your head around. Think of it as a composite indicator of temperature and humidity; it’s a better measure of heat as we feel it. For example, a bone-dry 32 degrees Celsius is tolerable—something I’ve experienced firsthand; you sweat and the sweat cools you off until you can get to shelter. But a muggy, humid 32 Celsius is difficult to breathe in, and no matter how much you sweat, all you can do is slowly overheat.

Let’s put this in perspective. The 2010 Russian heat waves, in which some 56,000 people died, saw wet-bulb temperatures of 28 degrees Celsius.3 The 2022 heat waves in the United Kingdom saw wet-bulb temperatures of 25 degrees.4 In Colombo, this is just another Tuesday. Our wet-bulb temperature stays steady at 26-27 Celsius throughout most of the year.

Baking hot streets, heat waves in the air. It wasn’t just me and some anecdotes: we have an actual problem. How did this happen, and why?

This is where we must examine two converging phenomena. First, Colombo has been urbanizing rapidly over the past several decades. Sri Lanka came relatively late to the urbanization game—it used to be called “one of the least urbanized countries” on the planet—but once we got there, we set off for the races. UN-Habitat data suggests that between 1995 and 2017, Colombo’s urban area grew by 9.57% a year—a pretty high figure, even by global standards.5

To my parents’ generation, there were only a handful of landmarks on the horizon: a smattering of towers, a single giant market (Pettah) where you could buy anything or get scammed out of every last cent, a few well-known shops at which to congregate. It was otherwise row upon row of homes. Fast-forward to today: I’m sitting in a cheap apartment, staring at miles of cheap apartments, office blocks, and the occasional glimpse of the oft-mocked Lotus Tower—a landscape my mother disdainfully calls the “concrete jungle.”

With this comes the second phenomenon. There’s a well-observed correlation between urbanization and higher surface temperatures. As people build more—more roads, more apartments—they remove greenery to make space, and replace leaves and earth with surfaces like asphalt and concrete, which trap and retain heat.

In a collaboration between Rajarata University of Sri Lanka and the University of Tsukuba in Japan, researchers used LANDSAT data to examine surface temperatures in Colombo at different moments during the decades-long process of rapid urbanization.6 The map on the left visualizes temperatures in 1997; in the middle, the same map with temperatures in 2007; on the right, the same area in 2017.

Three maps of Colombo, Sri Lanka, showing land surface temperatures in the urban area in 1997, 2007, and 2017. Green denotes lower temperatures, yellow moderate temperatures, and red high temperatures. As time goes forward, the maps become more yellow and red, with green areas nearly disappearing in the 2017 map.

Figure by Manjula Ranagalage, Ronald C. Estoque, and Yuji Murayama (MDPI).

These maps tell the story of a cooler city by the sea, and how it went from a pleasant 25-27 Celsius to a staggering 31 Celsius, or more: a sprawling fungus of red heat, spreading tendrils in every direction. The old-timers weren’t just being nostalgic; in their time, it would indeed have been much, much cooler.

As urbanization spread, so did the loss of green spaces—especially trees. As the surface-temperature study’s authors point out, this happened across the central business district, near the harbour, across the coastal belt, and along the road networks. Greenery, which cools areas by providing shade and heat loss through evaporation, began to vanish, replaced by mounds of concrete, steel, and asphalt. These surfaces store heat during the day and exude it at night, leading to the conditions I’ve been describing: an unrelenting heat from above during the day, and below after dark.

I wanted to understand just how much this effect might have intensified since the study’s measurements, because frankly, 2017 feels like a distant memory. While I couldn’t replicate the entire study, I had a trick up my sleeve: Google and the World Resources Institute have a project called Dynamic World that provides incredible satellite imagery maps of land cover.7 Using deep learning, Dynamic World tries to figure out whether a given pixel is water, trees, grass, cropland, and so on. And unlike the LANDSAT imagery used in the paper, Dynamic World uses Sentinel-2, a newer satellite with better sensors.

The results look dreary. Red here indicates built-up areas, a rising tide of artificial materials baking in the sun. Green and blue are self-explanatory. The first image is zoomed out, looking broadly at the same area that the LST maps did:

A satellite map of Colombo, Sri Lanka. Red denotes built-up areas, green undeveloped areas, and blue water. The map is mostly red, showing the landmass being dominated by human-built structures and infrastructure.

Image by Yudhanjaya Wijeratne, created using Dynamic World. This dataset is produced for the Dynamic World Project by Google in partnership with National Geographic Society and the World Resources Institute.

Here’s a closer view, which shows just how much of the city has become a contiguous mass of artificial surfaces:

A zoomed-in satellite map of Colombo, Sri Lanka. Red denotes built-up areas, green undeveloped areas, and blue water. The map is mostly red, showing the landmass being dominated by human-built structures and infrastructure.

Yudhanjaya Wijeratne, created using Dynamic World. This dataset is produced for the Dynamic World Project by Google in partnership with National Geographic Society and the World Resources Institute.

What happens when we have such an endless, uninterrupted mass of concrete and asphalt? This is where urbanization and temperature converge to create the urban heat island effect.

The urban heat island effect was first described in 1818, although not by that name. Based on detailed temperature measurements collected in London, British chemist and meteorologist Luke Howard noted that urban areas tend to have higher temperatures than surrounding rural expanses.8 By the outbreak of World War II, researchers attempting to understand local climates were documenting the phenomenon all over the world and trying to figure out its effects. In general, they found that daytime temperatures between urban and rural areas tended to have differences between 3 and 5 degrees Celsius. At night, the differences were more intense: urban areas cooled much more slowly. The difference between an urban area at night and a rural area could be as much as 12 degrees Celsius.

This doesn’t sound like much, and it isn’t if you’re in a cold country. An increase from 10 to 15 degrees Celsius might actually seem like a welcome change. However, if you’re living on a tropical island, especially one that’s quite humid, a 5-degree increase is the difference between a comfortable day and heat-wave conditions. This is where that nasty foe, the wet-bulb temperature, kicks in. Past a certain point, body heat is no longer being effectively carried away by sweat.

How do the denizens of Colombo counter this? Why, air conditioning, if you can afford it, and opting for private transport. These are two of the great boons of Sri Lankan city life. But each dumps more heat into the environment.

The effect never stops in the hot months. Buildings heat up, they stay hot at night, and come daytime, they heat up again. Concrete-slab roofs, in tropical conditions, become miniature ovens.9

And this is how you get to me, sitting out here on a cramped balcony at midnight because it’s too hot to sleep inside. Stick some soil in my apartment and call it a greenhouse. Now add the other negative effects of the urban heat island effect: elevated ground-level ozone, increased mortality, increased energy consumption, more greenhouse gasses, increased hospitalization of children and the elderly, and less biodiversity, because of the death of urban plants and birds.

The dead tree gives no shelter, the cricket no relief.

So, how do we get out of this mess? This is the moment where I ought to reach into my science-fictional imagination and pull out the grand ideas. Artificial clouds, or rockets heading for the sky, spreading reflective particles to block out the sun.

Before we blast into the stratosphere, let’s look at the approaches that exist today.

The first approach is the realm of ambitious makeovers. The push for greener cities has increased dramatically over the last decade. Serious funding and thought are being spent by big international movers and shakers—including the Asian Development Bank,10 the UN’s Food and Agriculture Organization (FAO),11 UN-Habitat,12 and the EU Commission13—and this is to say nothing of the millions of smaller pushes that happen before something gets this big.

This kind of globalist, top-down push lends itself to elaborate visions of the future, ones in which the nation-state plays a central role. Take, for instance, China’s Liuzhou Forest City, designed by Stefano Boeri Architetti, which will supposedly contain a million plants built into almost every visible surface. The idea is that this will keep the temperatures down and the air much cleaner than in a normal city.

A computer-generated aerial image of a high-tech green city, with futuristic buildings, a sleek tram line, all surrounded by dense forest. The rooftops and sides of buildings are festooned with green plants.

Liuzhou Forest City. Image courtesy of Stefano Boeri Architetti.

It’s not a bad idea, at least as far as the math is concerned. In my previous example of data collection from the streets of Colombo, our team logged both shaded and non-shaded areas. Shaded areas were those that had some manner of greenery, or even those that rested in the benevolent shadow of a larger building. Under the same sun, we read differences of up to (and sometimes more than) 20 degrees Celsius between exposed surfaces and shaded areas.

However, I’m skeptical of these grand ambitions. Grand plans never survive contact with reality, even in totalitarian regimes. The UK’s garden cities movement has seen its fair share of failures,14 and the same goes for high-tech “smart” cities.15 Large, centrally planned projects like these tend to encounter two problems.

One, they’re expensive and difficult to implement. Reorganizing Colombo to reduce the urban heat island effect would be a nigh-impossible challenge, involving billions of dollars and a nightmare of legislature and bureaucracy. Given that Sri Lanka’s economy has collapsed, well, good luck with that.

Two, they often ignore and brutally rewrite the shape of local communities. We can turn to Jane Jacobs’ work in The Death and Life of Great American Cities,16 or to more recent documentation from Colombo, where poorer communities have been forcibly evicted into government housing against their will.17 The incentives of large, top-down change are written by those who have power over such systems; as Jacobs argues, these empowered elites and their metrics for success tend to oversimplify and overlook the lives, cultures, and habitual patterns of people who actually live in the places being changed.

Colombo, in particular, has been on the receiving end of many ambitious and all-encompassing Plans. I capitalize the word here because these Plans are giant political projects, imbued with the character and values of those championing them, and because they never seem to evolve from Plans to Action; they’re too big-picture to become reality; they exist in an abstract well of good intentions and power plays.

There’s the Colombo Megacity project,18 an ever-mutating hydra often championed by Ranil Wickramasinghe, the current President of Sri Lanka (as of the time of writing, and since July 2022). Gotabhaya Rajapaksa, the former President, had his “Vistas of Splendor and Prosperity,”19 apparently inspired by his former stint running the Defense and Urban Planning portfolios and getting armed soldiers to chase young couples out of parks.

Then there’s the Urban Development Authority’s rather optimistic Development Plans.20 Unfortunately, given how tightly coupled the bureaucracy is with family political control and personal visions of grandeur, what seems to actually emerge into reality are “white elephant” projects: wasteful delusions of grandeur maintained at significant taxpayer expense. A good example is the Lotus Tower, a largely useless phallic shape,21 an emblem of Rajapaksa branding and political signage, which may take half a century to pay off at its current income.22

A complex system, once set in motion, is hard to change. Its inertia is greater than the sum of all moving parts. And a city is a complex system. The chaotic interactions of a city are the bane of a central planner—but those chaotic interactions are what make cities interesting, and bring a welcome measure of serendipity to our lives. They make our self-built panopticons bearable.

The second approach might be considered the realm of science fiction. Of solarpunk, at that—a particularly curious branch of science fiction that, like Janus, manages to look both forward and back at the same time. Solarpunk makes living sustainably an act of rebellion in a world that demands it die out; it sometimes professes a fondness for a simpler past, and sometimes it projects a simpler past onto the skeleton of a future, but either way, it says: The current way of doing things isn’t working. Let’s try something else.

This is where we, perhaps, ought to pay more attention to materials and design. Our ancestors, for example, built with stone, mortar, and lime, and had roofs with clay tiles. Large houses had madhamidhul—courtyardsprominently influenced by Dutch colonists. Adding to ventilation were narrow, brick-size slots higher up, where shade from the overhanging roof could prevent them from letting in too much heat.

Much of what we have adopted as modern architecture—concrete boxes, glass facades, Le Corbusier’s leftover aesthetics—was designed for cooler climates, for dwellings that had to retain heat instead of release it.

What should we do with this mismatch between architectural norms and climatological realities? Well, there are solutions to be found here. The problem is that to really work out, any solution has to hit two proverbial birds with one proverbial stone: One, our dwellings need to be more comfortable. Two, they need to have less impact on the environment, and consume less energy than conventional methods; otherwise, all we have is luxury for one at the expense of a livable world for many.

Let me spin you a yarn: in 2020, I had the idea of moving to a mountain and building an earthbag house for myself.23 For the uninitiated (or the slightly less eccentric, depending on how you look at it), an earthbag house is one where concrete blocks and bricks are replaced by polypropylene bags stuffed with earth. The bags are usually rice sacks, and the earth is usually sourced from the site itself. My logic was that building this was much cheaper, has a far lower environmental impact, and the higher thermal mass means it’s harder to heat up.

I bought a piece of an old estate half-ruined by tea plantations. I catalogued the trees, made careful plans for reforestry and regrowth. I studied old buildings in Sri Lanka; I went off to Nepal and studied earthbag houses there; I poked around the documentation from experimental architecture projects like France’s Guédelon Castle;24 I examined wind towers from the Middle East and Mediterranean regions; and finally, I set off to design.

But this, of course, required research. Digging into the realities of thermal mass and insulation and load-bearing gave me a newfound appreciation for older architecture, and not just out of nostalgia. As I learned more, I began to better understand the failures of my early attempts, most of which were standard modernist cubes. A courtyard here, terracotta tiles there, doors positioned for cross-ventilation - and suddenly I had a much better design on my hands, far more comfortable to live in.

Digging into materials had other benefits, of course. We’ve now been testing the shear strength of earthbag walls. They tick all of the boxes; they’re strong and sustainable. How strong? Testing by Geiger et al.25 and Jain26 suggests that such bags require loads in excess of 840 kN to fail. That’s close enough to concrete that we can use it for a house.

Close-up photo of a human hand holding a handful of dirt.

Photo by Yudhanjaya Wijeratne.

Even better for the economically minded: comparative costing shows that it’s far, far cheaper. My contractor estimated that the 3,500 square foot design I had come up with would cost some 36.9 million Sri Lankan rupees to build in brick: with earth, it comes to 16.8 million.

A direct comparison between Sri Lanka and anywhere is, of course, quite difficult. Labor costs, transport networks, fuel availability, building codes—all of these things play a part. But let’s convert these figures to U.S. dollars for the sake of argument: I’m spending about $50,000 for a house that would cost about $115,000 if built in brick.

The ultimate house that is emerging now, even as I type this, is a curious beast; half modern, half antiquated, but far more livable, consuming far less energy to keep cool, and costing less than half of what I’d expected it to be. Worth it, no?

Of course, I’m going to shill for my own approach—sunk-cost fallacy at play—but mine’s not the only one out there. Solarpunk dreams of many possibilities.

In the wake of the 2004 tsunami, which left tens of thousands dead and displaced in Sri Lanka, Canadian engineering researchers Bryce Daigle, Kevin Hall, and Colin MacDougall explored the idea of earthbag housing.27 They also noted that bamboo grows quite well in the south of Sri Lanka, making the country a great candidate for bamboo-frame housing. Bamboo also deals with heat better.28 Both methods are cheap, carry a lower environmental impact, and are technologically and structurally viable. Bamboo, in addition to being a fast-growing grass (and therefore more sustainable), also shows great promise as far as thermal characteristics go.29 That’s another potential solution that reduces a whole layer of energy and emissions.

And this is to say nothing of more sophisticated approaches using modern materials science, methods better suited to scale. One thing is clear: we can build in ways that make more livable cities—from large-scale design to small-scale materials choices. And we owe it to ourselves to critically question design trends imported en masse from colder countries, and to gaze upon the chaos we create for ourselves, and dream better. The arrow of time moves in one direction: towards urbanization.30 We can either go forth into the future wisely, with the best information we have on hand, or blunder around like idiots in a dark forest, waiting to be devoured by our own creations.

Then there is the third approach: the carrot and the stick.

Let’s return to Colombo. Once upon a time, the Portuguese, the Dutch, and the British ran this place: they used it as a harbour and a market town. Colombo prospered while the rest of the country suffered—hence the old saying Colombata kiri, gamata kakiri. Loosely, milk for Colombo (that’s the good stuff); yellow cucumbers for the village (that’s the cheap stuff).

As Colombo prospered, its population grew. It remains “The City” towards which people gravitate. Students who do well elsewhere in Sri Lanka come to study in Colombo; people looking for work come to Colombo for jobs.

And as these populations grew, urban planning remained primitive, at best. Urbanization is not the enemy: unplanned, uncoordinated, winner-takes-all urbanization is the enemy. Let’s compare Jane Jacobs’ observations about urban life to what unfolded in Colombo. Jacobs preached about the importance of sidewalks, noting that they were critical in making people feel safe, secure, and integrated into the social fabric of the city; sidewalks turn strangers into familiars, a city’s way of keeping itself safe and secure. Plenty of research has tested the efficacy of shaded sidewalks on the urban fabric;31, 32, 33 for those not inclined to research, a simple stroll down one of Colombo’s few remaining leafy corridors will do.

Aside from these rare verdant thoroughfares, Colombo’s sidewalks are the opposite. They’re tiny, haphazard, crowded out by everything other than walking,34 in a state of terrible repair,35 often physically dangerous to walk on,36 and are used as ad-hoc parking spaces.37 They’re also, as I’ve pointed out, baking, bereft of shade.

They’re also uncounted. The government’s Road Development Authority, despite logging the kilometers of major roads across the country, doesn’t count pavements and walkable spaces at all.38 The sidewalk is invisible in Colombo. If what is measured gets improved upon, then what is unmeasured is ignored.

Onto public parks, another favourite of Jacobs: she saw them as a focal point for communities, for multi-purpose uses, a center in the urban fabric, enclosed by buildings. Colombo’s public parks are a joke; one small patch in Viharamaha Devi Park, another in Independence Square frequented mostly by those who can drive there. The rest of the city must make do, exercising by dodging cars on roads.

I bring up parks because, again, research shows that greenery and shade help significantly counter the urban heat island effect.39, 40 Consider the social aspects a bonus; it’s useful enough even if we aggressively used greenery solely to prevent “furnace cities.”41 But this was thrown out the window a long time ago, at urban planning levels and otherwise. Cutting down trees seems to be an obsession on the part of Sri Lankan property owners. At every place I’ve rented, every year, the landlords cut down trees and shear branches, banishing shade. Some leftover relic of culture, perhaps, from the slash-and-burn agriculture we’ve practiced for thousands of years? Perhaps. Lack of incentives to keep green space around? Certainly.

There’s a story here. As Terry Pratchett would say, at the heart of it all, we’re not homo sapiens, the wise man—we’re pan narrans, the storytelling monkey. Stories bind us to paths leading to the future. And they don’t necessarily come from well-intentioned pamphlets: they’re more powerful when they arrive with small plans that progress, with concrete examples in the physical world, with the weight of aspiration behind them.

There’s a story in how we arrange our cities, in how we idolize the endless sprawl. Stories can be changed. They start small, and they end up spreading far and wide, holding dominion over all these crucial aspects of life.

The story of Colombo has been growth, fuelled by the construction boom that came about after the Sri Lankan Civil War ended in 2009. The mismanagement of this growth has left behind even the basics of city planning. Many cities have some level of zoning in play—this area is residential, this is commercial, and so on. In Colombo, we don’t.

In a research project I worked on once, we used mobile phone call records from millions of people in Sri Lanka to try and understand what parts of the city were primarily residential, and what parts were primarily commercial in nature. (The actual algorithm was simple—it examined load on cell towers during regular business hours.)

What we found was that the vast majority of Colombo simply defies classification. We have houses, giant offices, tiny grocery shops, restaurants, and schools all sitting right next to each other, on lanes far too small to accommodate all the vehicles that move around, backed up by a public transport system that has been deteriorating for a long time.

Nor do building codes seem to play much of a part in anything. They seem to exist,42 but I’d be hard-pressed to look at neighborhoods and say that the vague rules around open spaces and greenery are actually enforced.

What comes out of such a system? A kind of haphazard Moloch, vaguely reminiscent of Allen Ginsburg’s “Howl” (Ashcans and unobtainable dollars! Children screaming under the stairways! [...] Old men weeping in the parks!).43 There is little market for comfortable streets and green spaces acting as heatsinks. What we got instead was a creeping mess.

We could have managed this. The science was well established long before Colombo began its current process of rapid urbanization. Trapped in an endless cycle of war, debt, and economic ambition, we made our own little tropical handcart to hell.

So perhaps the thing to do is to change the story of Colombo: from growth to comfort.

Now, to change this story requires the carrot and the stick. To understand what might be a carrot and what might be a stick, we have to start with measurements.

As I’ve shown multiple times here, the idea of comfort can be measured, as the studies and self-propelled experiments described in this essay show. Air pollution levels, surface temperature, the ratio of green space to so-called “gray infrastructure,” or human-built structures, wet-bulb temperatures—these are easily measured with today’s technology.

Here’s a carrot, then. What incentives can we hand out for developments that improve on these things? There are things that might work at the scale of large projects, like requirements for maintaining public green spaces or shading proportional to the size of the project. There are even things that might work on a small scale: an experiment in Florida44 showed that low-income households are more willing to participate in rebate programs that change their lawns to low-input, more environmentally friendly landscapes. The poor were willing; the rich, not so much. What we might have to do is spawn a veritable zoo of research around incentives, tied to methods that improve comfort for the whole.

The second step is to regulate: not ambitiously, but competently, and in an enforceable manner. Sri Lankan housing regulations are a bit of a joke; theoretically, there is a process of approval, involving architects—but in practice, most people build first, without waiting for approvals. Even complex changes may not be penned by an architect at all, but by the closest available draughtsman. And even when approval is sought, it might be a provincial clerk who approves it, or even a public health inspector. Corruption is rife within the system, of course.

Enforcing regulations for smaller homes might be immensely difficult. But larger-budget, high-visibility projects like apartment complexes, roads, parking lots, and office buildings already require more extensive approvals and a great deal more prep work than waking up one day and deciding to build an extra bedroom.

So we regulate the visible. This is the stick. Large projects can have requirements to maintain a certain amount of greenery for the volume and area that they displace, or other schemes that help counter this issue of heat. Maybe they contribute to an urban heat island effect control fund; maybe they agree to maintain trees or shade along a set of roads nearby. Meeting these requirements can be incentivized; they can also be baked into the approval process. Bonus points if they can bring something new to the table—provided, of course, that the research backs it up. Policies and incentives can serve to make large organizations care, especially at the scales where a single percentage of revenue in savings far outweighs the cost of maintaining a garden or a shaded parking lot. Now the carrot and the stick work together.

There is one more step that I might add. This is where we move away from the central planners altogether and go down to the level of the grama niladhari (GN) division. The GN division is the smallest administrative unit in Sri Lanka: there’s 14,000 of them that combine to form districts, provinces and so on.45

GNs are an odd beast. Typically, GN officers have some community power in villages, but less so in cities, except when it comes to rubber-stamping documents or rolling out election processes. Now, developers and property owners might not have much incentive to think beyond the boundaries of their properties, but the GN has some claim to representing the neighborhood. It might not be a very effective tool right now, but I’d argue that it should be charged with making each GN division comfortable. This might mean organizing drives for planting trees for shade along the roads; it might mean setting aside a certain amount of green space as commons. Either way, let’s try something that we often ignore in policy: give the communities the tools of measurement, and let them figure out how to optimize themselves. Let the overall environment of city-level carrots and sticks empower these communities, rather than ignoring them.

It will be chaotic. Such community-led improvement efforts have often failed; consider the horror story of the Hewlett Foundation’s investment in the Neighborhood Improvement Initiative, in California’s Bay Area.46 Changing a story isn’t as neat and easy as dreaming up a radical new city from scratch; it’s tough to deal with so many people, and the idea of comfort will need to be thoroughly tested, its methods of observation worked out to be as fair as possible while erring on the side of whatever chips away at the urban heat island effect. But done right, we might encourage petri dishes of experiments that can be observed, scaled up, and implemented elsewhere.

Colombo isn’t unique in this story. I’ve described much of the world I’ve traveled and worked in: cities in South and Southeast Asia, trapped under the relentless need to develop rapidly, to cater to large populations with barely enough time and money to build infrastructure. Famously, New Delhi—a city of dense smog and Kafkaesque traffic jams—needs to build 700 to 900 million square meters of urban space annually, just to keep up with the continuous influx of people.47 That’s adding a new Chicago every year.

We might not have the budget, or the political will, for a Ministry for the Future. But with knowledge, with stories, we might end up with a million smaller such ministries, each trying out different things, stumbling upon old hacks, discovering new ways, exploring all the dimensions of change. And, as long as we’re heading for cooler, more walkable, more livable cities, it might be worth stumbling along. Indeed, I’d say it’s necessary.

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