Smoke and Sweat: City Design in a Warming World

There’s a concept in urban design, called the “15 minute city”, that has been gaining a lot of traction in some circles. The basic idea is that everything a person needs in their day to day life ought to be within 15 minutes’ walk from their home. That means jobs, groceries, doctors, and so on. This tends to come with limitations on car use within those cities. One proposal I’ve heard is that people can drive around cities on ring roads all they want, but if they drive across the city more than a set number of times, they have to pay a fine. People on the right, of course, have folded this into their all-encompassing theory of how everything is a conspiracy, but that’s not actually the point of this post. The point of this post is that the 15 minute city concept, while a fantastic idea, may be too little, too late.

I’ve got a few points that I make repeatedly, and in different ways. We need to do more than we’re doing. We need to move food production indoors. We need to bring plants into our cities more. We need to end profit-driven overproduction. We need to start building enclosed cities.

It’s that last one I want to talk about today, in light of the Nova Scotia wildfires, and the dangerous and dramatic air pollution they have caused in the United States. To begin with, I don’t mean building a glass bubble over our cities. To me, that seems like a terrible idea, and utterly impractical. No, what I want has more to do with tunnels and building layout. When I moved from the US to Glasgow in 2019, I had to fly into Germany, drive to the Netherlands, and take a ferry out of Rotterdam to get to Great Britain. Because of the rules around traveling with pets, we had to spend a couple nights in Frankfurt, so that we could go to a German vet to vet our pets. The Airbnb we stayed at was a family’s extra bedroom, and what caught my attention was the fact that their grocery store was literally in the same building as their apartment. When Tegan and I needed to get supplies for our drive to the coast, all we had to do was go downstairs. Add in a connected subway system, or even enclosed walkways between buildings (underground or otherwise), and suddenly people might not need to go outside for days or weeks at a time.

In my youth, the very concept would have horrified me. In many ways, it still does. While I’m nowhere close to being the outdoorsman I once was, I value time outside, and I value being able to see wildlife. The idea of deliberately designing a world in which people never need to go outside is disturbing. What’s far more disturbing is the fact that this is the direction in which we must start moving, if we want to survive.

Normally, when I talk about this kind of urban redesign (folks in the country will need other solutions, and we absolutely need to invest resources in helping them), the danger in question is heat. The rise in global temperature has, predictably, led to a rise in lethal wet-bulb conditions. Basically what that means is that the combination of heat and humidity mean humans can no longer cool themselves by sweating. It just doesn’t work. That means that pretty much anyone can develop lethal heat stroke pretty quickly. I like Wikipedia’s breakdown of this:

The wet-bulb temperature (WBT) is the temperature read by a thermometer covered in water-soaked (water at ambient temperature) cloth (a wet-bulb thermometer) over which air is passed.[1] At 100% relative humidity, the wet-bulb temperature is equal to the air temperature (dry-bulb temperature); at lower humidity the wet-bulb temperature is lower than dry-bulb temperature because of evaporative cooling.

The wet-bulb temperature is defined as the temperature of a parcel of air cooled to saturation (100% relative humidity) by the evaporation of water into it, with the latent heat supplied by the parcel.[2] A wet-bulb thermometer indicates a temperature close to the true (thermodynamic) wet-bulb temperature. The wet-bulb temperature is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only.

Even heat-adapted people cannot carry out normal outdoor activities past a wet-bulb temperature of 32 °C (90 °F), equivalent to a heat index of 55 °C (130 °F). The theoretical limit to human survival for more than a few hours in the shade, even with unlimited water, is a wet-bulb temperature of 35 °C (95 °F) – equivalent to a heat index of 70 °C (160 °F).[3]

This isn’t a matter of sucking it up and living with the heat. It’s a matter of humans being physically incapable of living with the heat. All humans. If it’s just moving between nearby air-conditioned buildings, most people would be fine, but I’m not so sure about they very young, the very old, and folks who’re sick or have disabilities. This is also very much tied to the manufactured crisis of homelessness. Being unhoused is already incredibly dangerous, and while there has been a decline in lethally cold conditions (faster than the rise in warm ones), the overall rate of warming is on the rise, and it’s a lot easier for someone without shelter to stay warm on a cold night than to cool down on a hot day.

The heat and humidity are not, however, the only things that we need to consider.

As most of you are no doubt aware, Nova Scotia is burning, and a huge area to the south of those fires is being smothered by the smoke, with New York City getting the most attention:

The image shows an NYT headline reading: "Swaths of North America Are Shrouded Under Unhealthy Air", with an image below it captioned, "View of Manhattan, via EarthCam". The image below is a compilation of four photographs of the Manhattan skyline. The first, at 10:02am shows the city pretty clearly, with a bit of haze in the air. At 11:56am, the whole scene has a dingy yellow tint, and details like tower reflections in the water are no longer visible. At 12:53pm, the dingy yellow has taken over, and Manhattan is little more than a silhouette of its skyline. At 1:53pm, the silhouette is still there, bit the air is now a deep, orange color.

The image shows an NYT headline reading: “Swaths of North America Are Shrouded Under Unhealthy Air”, with an image below it captioned, “View of Manhattan, via EarthCam”. The image below is a compilation of four photographs of the Manhattan skyline. The first, at 10:02am shows the city pretty clearly, with a bit of haze in the air. At 11:56am, the whole scene has a dingy yellow tint, and details like tower reflections in the water are no longer visible. At 12:53pm, the dingy yellow has taken over, and Manhattan is little more than a silhouette of its skyline. At 1:53pm, the silhouette is still there, bit the air is now a deep, orange color.

People are being urged to stay indoors as much as possible, and to wear masks to help filter out the smoke. I remember when COVID hit, Rebecca Watson mentioned that she already had masks, because California has been getting this same treatment over the last decade. Now I’m wondering how many people in NYC were prepared for this crisis because they’re still masking for COVID. Make no mistake: people are being sickened and killed by this.

But this goes further than just a couple reasons why people might need to remain indoors. Heat and air pollution are not separate, as the former often makes the latter far worse. If it weren’t for the smoke, New York would be having a pretty normal time of it, with a today’s high being 72°F/22°C, but what if this was happening at the same time as a heat wave?

High heat and air pollution are each problematic for human health, particularly for vulnerable populations such as older adults. But what happens when they hit at the same time?

We examined over 1.5 million deaths from 2014 to 2020 registered in California – a state prone to summer heat waves and air pollution from wildfires – to find out.

Deaths spike when both risks are high

The number of deaths rose both on hot days and on days with high levels of fine particulate air pollution, known as PM2.5. But on days when an area was hit with a double whammy of both high heat and high air pollution, the effects were much higher than for each condition alone.

The risk of death on those extra-hot and polluted days was about three times greater than the effect of either high heat or high air pollution alone.

The more extreme the temperatures and pollution, the higher the risk. During the top 10% of hottest and most polluted days, the risk of death increased by 4% compared to days without extremes. During the top 1%, it increased by 21%; and among older adults over age 75, the risk of death increased by more than a third on those days.


There are several ways the combined exposure to extreme heat and particulate air pollution can harm human health.

Oxidative stress is the most common biological pathway linked with particulate air pollution and heat exposure. Oxidative stress is an imbalance between production of highly reactive molecules known as reactive oxygen species, or ROS, and the body’s ability to remove them. It’s been linked with lung diseases, among other illnesses.

Antioxidants help clean up these molecules, but particulate air pollution and heat disrupt this balance through excessive metabolic ROS production and lowered antioxidant activity.

Our research also showed that the effects of particulate air pollution and heat extremes were larger when high nighttime temperature and pollution occurred together. High nighttime temperatures can interfere with normal sleep and potentially contribute to chronic health conditions such as heart disease and obesity, and disrupt how the body regulates temperature.

Older adults may be more susceptible to effects of extreme heat and air pollution exposure, in part because this stress comes on top of age-related chronic health conditions like heart disease, high blood pressure, diabetes or chronic lung disease. Impaired body temperature regulation in response to heat can also occur with aging. And older adults may be less mobile and therefore less able to get to cooling centers or to medical care and be less able to afford air conditioning.

We have reached a point, with the warming of this planet, where survival will increasingly depend on things like air conditioning and air filtration. Both of these things cost energy, and if we are using fossil fuels to generate that energy, then we will be making the problem worse, simply by trying to survive it.

This is why it was so important that we transition away from fossil fuels before it got to this point – not just because it might have helped us avoid a great deal of needless death and suffering, but also because we’ve always known that rising temperatures would mean rising energy demand from things like air conditioning. What’s more, our current grid can’t handle the power demands of a heat wave, resulting in power failures that place many more people at risk.

We’re at this point thanks to decades of procrastination by our so-called leaders, and they seem committed to continuing that procrastination until they die, while working to ensure they’re replaced by people who’re likely to continue that pattern. Without drastic action, and a real change in direction, it will keep getting worse, and there is no limit to how much worse it can get. Because there is no limit to the greed and callousness of the rich, we need the power of an organized working class to have any shot at building a better world. That will come through community organizing, and workplace organizing. Neither are easy, but until we have the ability to bring the system to a halt, those who’re enjoying the ride will keep on going forward, driving us straight to hell.

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  1. brightmoon says

    I live in NYC. You could smell the smoke . It was like being downwind of a neighbor’s barbecue. It was that bad . I didn’t go outside for the last 2 days . My throat is a little raw but otherwise I’m fine. People have ended up in the hospital. . Even animals are showing signs of kidney damage from the high heat mixed with humidity . Humans aren’t the only species affected by this.

  2. says

    And yet Fox just had some guy on to insist that the EPA’s studies say there’s no danger.

    The same guy has made similar arguments about secondhand tobacco smoke, asbestos, and radiation, so I guess that tracks.

  3. brightmoon says

    I meant that global warming is causing species wide kidney damage especially around the equator.

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