The American West is figuring out how to keep cool | Hacker News Reader

The American West is figuring out how to keep cool

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50 pointspseudolus170 comments

The answer is trees everywhere in numbers that you don’t find in western cities. Like 100x the number of trees normally found in a city. The benefits aren’t just in temperature but also air quality, biodiversity, etc etc.

Edit: for those saying “But there’s not enough water”, I strongly suggest reading “Rainwater Harvesting in Drylands and Beyond” written by Brad Lancaster in Arizona. For those who don’t want to read the book, check out his TED Talk here (warning: his enthusiasm is infectious and you’ll want to read the book afterward): https://m.youtube.com/watch?v=I2xDZlpInik

Works really well as long as you can find trees that don't consume water.

The challenge in these western cities is that they don't even have enough water to run the taps. The reality is that the western US should not be this populated, period.

That's exactly what Phoenix is doing[1], well not no water but they're native and use very little.

[1] https://www.phoenix.gov/oepsite/Documents/Tree%20and%20Shade...

I live in Phoenix, and have seen the tree planting.

There is a lot more that could be done that is not done. From my eyes, it looks more like, there are X number of trees that need to be planted and they are planted to fulfill those goals.

There is little in the way of consideration for sunlight patterns, rainwater patterns, microclimates, planting methods, etc.

While imperfect sounding, just getting trees in the ground and then moving the goalposts to constantly increase the number, is a huge step forward. I think once in the ground, nature will take over and adapt.

I live in Portland, a place covered in trees and there’s definitely plenty of water for them. When I travel through parts of East Portland, it’s very noticeably hotter and there’s a noticeable lack of trees. The problem seems to be part political, part budget and part passing the buck (BUT WHOS GONNA TAKE CARE OF THEM??). It’s very frustrating.

True, I should have been more precise; I was talking about the southwest. The PNW is a wonderland.

The vast majority of water in western US goes to agriculture. You can of course make the obvious argument about local food production being necessary, but if the choice is more people can drink water at the cost of more expensive almonds and alfalfa, I'm ok with that. The idea that the west has done anywhere close to enough to optimize water consumption is not right, there's quite a bit of headroom left (that should be used to replenish aquifers).

People might think you're being hyperbolic about the alfalfa but you are not. 25% of Colorado River water is used to grow alfalfa which is crazy given the contention around Colorado River water rights.

https://coloradosun.com/2024/04/04/research-colorado-river-w...

One of the more enduring way of restoring the aquifer is to restore the riverlands the way it had been before we hunted out all the beavers. That is, to slow down water flow in the hydrological cycle so that it spreads out and meanders throughout the land.

Treated wastewater is almost waste itself, because at least in the United States we're reluctant to use it for agriculture for the obvious reasons. And trees aren't particularly large consumers of water, because the irrigation methods are non-lossy. Not spraying sprinklers up in the air so half is lost to evap. Or flooding little furrows in between the rows of a crop. It's not that big of a challenge, at least water wise. Infrastructure, if anything, is the problem... cities would have to go digging up a fuckton of sidewalk, and spend extra on maintenance every time there's a leak. Worse still, is having two separate water systems (can't connect to the potable water mains).

Drip irrigation isn't always good for trees to develop robust root system.

Wastewater depends ... residential greywater can be used onsite if the residents are careful about the type of detergents they use. There are methods to treat blackwater onsite (more than just a septic tank and a leech field).

For trees, I think the biggest factor is if you use woodchips in a basin. Even a six-foot diameter with 1 ft depth, filled with arborist chips makes a huge difference in water retention and nutrition for the trees. These are rain water harvesting structures that do not require a drip system.

Which cities? Metro Phoenix non-agricultural water usage is flat over the past 30 or 40 years despite experiencing double digit population growth for most of that time. Agriculture is the majority consumer and incentives and stewardship norms are evolving.

The desert has always been a place humans needed technology to thrive in, since the ancient Gardens of Babylon or the Phoenix canals constructed by the Native Americans. The challenge is we need to invest in technology (Did you know the AZ border is only 60 miles from the Sea of Cortez?).

There are lots of solutions that don’t involve throwing our hands up and saying “aw shucks it’s too hard to build infrastructure so I guess we should go home”

Yip I've lived in many places where you have months of 40C+ (~104F), but when you past through a nice forested area the temperature just instantly plummets.

Water is the problem. You don't see a lot of trees in southwestern cities because we don't have the water to keep them alive.

I would argue that the problem is maintenance. Trees need to be pruned, watered, checked for pests, can get into sewer lines, waterways, etc. To sum up, they require work and one thing that governments hate is extra work.

I would argue that it's not so much that governments dislike extra work but rather that the populace dislikes the additional tax expenditures that accompany it.

Yet municipalities never seem upset by all the future maintenance required when they allow new subdivisions with roads, sewer, water infrastructure to support in perpetuity.

Something I've seen in many cities around the world (though never once in the US) is cities that essentially integrate literal forests into their layout. It's not the typical aesthetic or small-park type setting with a few dozen neatly sculpted and organized trees that would shortly give way without constant attention, but literal overgrown and completely self-sustaining forests. The closest I could find with an image search was apparently in Melbourne. [1] Imagine something like that, but somewhat more chaotic and natural. It works really well, but runs contrary to the sort of sterile aesthetic that most Western cities generally aim for.

[1] - https://i.pinimg.com/originals/ec/c3/09/ecc309a7ebfb8f2235f1...

I went to college in Austin, and I feel like they do this decently well.

Central Park New York ? Tokyo Meiji Forrest ?

It's not a forest because that kind of growth isn't native, but San Diego has one of the nation's largest urban parks in Mission Trails Regional Park.

Portland is kind of like this

San Francisco has Golden Gate Park, Mt Sutro, Lands End, and the Presidio as forests. I think park maintenance in those places is less to ensure trees thrive and more to keep up trails, remove hazards, etc.

Yet places like Arizona are famous for their lush green lawns and golf courses.

Golf courses, yes. Lawns? I grew up in Tucson and rock lawns are standard. I'm sure I've probably seen grass lawns in Southern AZ that weren't turf, but I'm having a hard time remembering one.

> I'm sure I've probably seen grass lawns in Southern AZ that weren't turf

FYI, "turf" doesn't mean fake grass.

https://en.wikipedia.org/wiki/Artificial_turf

https://www.merriam-webster.com/dictionary/turf

Not sure what you mean by those links, but they seem to pretty clearly indicate that "turf" does not imply "artificial"; the meaning of the term always includes real grass, so using "grass" and "turf" as if they're mutually exclusive alternatives makes no sense.

I mean to imply that you’re straight incorrect on top of being pedantic. The dictionary link provides definition 1b for turf as “an artificial substitute for this (as on a playing field)”.

Not only have you added nothing of value to the topic at large, you provided incorrect information. The intent was obvious enough that you felt confident “correcting” me. Thanks for playing.

I don't think you're parsing the dictionary correctly. Using "turf" to refer exclusively to artificial turf is not supported by the dictionary you cite, and is unnecessarily confusing and distracting. In the future, just be explicit and use the term "artificial turf".

Looking at satellite imagery for a few minutes, I couldn't find a single lawn in Tuscon, but in Phoenix they are all over the city. I believe Phoenix has a lot more local water though. Native American civilizations had over 100 miles of canals and irrigated agriculture along the Gila, which is why American farmers settled there in the first place, reusing some of these canals even.

Yeah, that tracks. They do have more local water, but also fairly affluent areas that can afford to maintain a green lawn in 120F summers. Totally stupid.

Phoenix's farmlands and orchards have been taken over real estate development. Real estate development and speculation has been the main driver of economic growth in Phoenix since the 60s, and accelerated with the widespread use of A/C.

I don't think people in Phoenix have lawns because there is more local water.

As far as Tuscon, Brad Landcaster's neighborhood has a tree canopy, and it's all watered by rainfall, and street storm water runoff harvested in eddie basins.

Well if its not due to water supply then what lead most all development in tuscon to have rock lawns or desert scrub, while all over phoenix in neighborhoods rich and poor there are grass lawns? I assume this has to do with how local water is priced or how local ordinances are applied with respect to the available water supply, although maybe I am wrong in that assumption and that water has really nothing to do with it.

Strictly speaking, Phoenix does have access to more water.

Tuscon is on top of a mesa, and its biome is the upper Sonoran. It's not quite high desert. The aquifer in the mesa has long been drained and Tuscon has to pump water from the central canal uphill to the mesa.

But it isn't as if the Phoenix is really flushed with water. An accident of legacy water rights from Colorado via the canal makes water available, but that doesn't mean that water supply is local nor sustainable.

Further, those existing water rights are being challenged by Native interest -- water rights are recognized by the age of the claim as senior water rights. Arguably, native tribes have the most senior rights, but even those claims that have been acknowledged by the legal system has not been historically enforced.

Tuscon is also where the Arizona laws allowing greywater was pioneered, as well as curb cuts. It seems to me there is more interest in this kind of stuff in Tuscon than there are in Phoenix.

Here are Tuscon development that are neither lawns nor xeriscaping:

Brad Landcaster's neighborhood - https://www.youtube.com/watch?v=KcAMXm9zITg

University of Arizona - https://www.youtube.com/watch?v=HtabtkWMxBc

> But it isn't as if the Phoenix is really flushed with water. An accident of legacy water rights from Colorado via the canal makes water available, but that doesn't mean that water supply is local nor sustainable.

Odd to be well so informed overall but somehow not aware of the SRP?! I think Phoenix is flush with water because of the CAP and SRP combo. It sits on the confluence of the Salt and Gila rivers while CAP water comes down canals from the CO plateau.

Lawns are illegal in most of Arizona actually. Golf course make money and prioritize that over the environmental impact.

Also, most of those golf courses are taking advantage of 150+ year old water rights laws that no longer make sense in our current environment.

That is either patently untrue or there are a whole lot of loopholes. I used to live in Phoenix more than 20 years ago and had a lawn that matched anything you'd find in Chicago. I still have about a dozen friends living in the Phoenix metro and all of them have at least a patch of lawn, not to mention the grass areas maintained by the HOA.

I live in Phoenix now, and there are plenty of lawns.

Mendoza handles this by guiding water into the city from nearby mountains. Of course, you have to have suitable nearby mountains to do this... But the city, in a desert, is filled with trees!

Sam Kinison had it right in the 1980s. DON'T LIVE IN THE DESERT!!! OOOHHHH!!!!

Huh, I've thought it was a really bad idea when I was aged 21. How much more evidence do we need that these are bad ideas? Few things live there, hows that for a reality check?

The worst is that much of this is state/nation backed (at least initially), so it's a bit of a drain as well.

We absolutely need to massively scale solar powered desalination plants in hot places. I realize there are issues around releasing high salt content water back into the ocean but there has to be ways to do that effectively. For instance, heavily dilute the high salt outflow with a lot of ocean water before releasing it back into the ocean.

There are much easier ways to sustain an ecosystem in the desert without bringing in technology like that.

If your goal is to have a basic ecosystem. If you want a thriving metropolis, something a lot of the Middle East is aiming for, it’s a no brainer.

In the case of Tuscon, where Brad Landcaster lives, it is the upper Sonoran desert. You go look at the wildlands, and the trees do fine. There are plenty of water to support the life that is there.

There are lots of ways to work with that problem and Brad Landcaster pioneered them in Tuscon, including curb cuts. You use eddie basins (and other design patterns), along with native perennials. In the case of Tuscon, those would be the native trees of Sonoran -- palo verde, mesquite, cholla, prickly pear, etc.

The curb cuts he pioneered inspired municipal laws, and Tuscon started implementing those and their own basins.

The mesa that Tuson sits on top of used to have an aquifer. That's been depleted and the city has been pumping water uphill. It does not have to be this way.

> Brad Landcaster lives, it is the upper Sonoran desert

Hmmm. I wonder if he's related to Don Lancaster, who also lived in the Upper Sonoran Desert. Was mentioned on HN that he passed away last year.

https://en.wikipedia.org/wiki/Don_Lancaster

Drip irrigation and trees adapted to dry climate (eucalyptus?) should not increase region water use significantly.

>eucalyptus

I don't think spreading poisonous trees across the American southwest is a good plan.

On the other hand, spreading species of eucalyptus that koalas can eat and also bringing in koalas sounds like an excellent plan!

There's a fungal infection here in Phoenix that eats eucalyptus. All of the eucalyptus on my street have been infected and died.

It's not really about planting a single species, but rather, introducing new ecosystems, so no one species is going to go wild and out of control.

Drip irrigation is not that great for trees that need to develop its root systems (to gather more water, and to survive monsoon winds in the Southwest).

If you do drip irrigation for such trees, at the minimum, the drip would need to be expanded as the canopy expands, and/or use deep watering spikes.

Better would be a deep mulch basin with intermittent deep watering.

In Phoenix (which is mentioned in the article), people have a tendency to use hybrid palo verde, trim the trees so they are more like the idealization of trees rather than the canopy pattern found in the wildland, and then have xeriscaping in a way that doesn't promote root growth. Some people will drip irrigate. The result are trees that blow down easily with the monsoon winds (which occasionally turn to hurricane strength gusts). It's not too hard to get chip drops during monsoon season because of poor stewardship.

In the nearby local park, there were a number of trees planted. That's good ... but the placement was not carefully chosen. Some of them will grow to shade the west setting sun along pathways, which is great. But there were other trees that were grown within the canopy of the overstory trees -- they are not going to grow great. They were also planted by digging large holes to fit them, but without any understanding of how rainfall will collect. Turf was added back (grasses compete with trees to fight over whether it turns into grassland or forest), rather than using mulch basins; the only reason they will do ok is because the park services flood irrigates the park. Lastly, the tree species chosen didn't look like they were carefully considered.

Mainly, the program looks like it has metrics on the number of trees planted, but there was nothing in the program or policies about tree species selection, planting methods, consideration of sunlight and rainfall patterns.

There was some research posted on here a while back which suggests trees can someone encourage rain.

Phoenix uses twice as much water as NYC with half the population.

https://www.youtube.com/watch?v=AjQuZfkU1jI

Where do you put the trees when 1) many cities require a certain amount of parking for buildings and 2) surface parking lots are the cheapest form of parking? Cities lack trees because the requirements and incentives directly lead to paving the whole place over.

There's plenty of measures e.g. buildings close together so they can shade passages and funnel wind, literally look at middle eastern cities and you'll see it.

Most of the US Southwest is naturally desert. There are only a few kinds of trees- such as the native palm that can live in these harsh conditions, and they naturally would only occur in arroyos or places where water accumulates and wind speeds are lower during storms. The soil is also just sand, and cannot support a large tree. The Los Angeles area is filled with non-native trees that are planted in sand and watered at great expense, but they fall and destroy houses and cars everytime it gets windy.

Brad Landcaster lives in Tuscon and has successfully been able to implement the rainwater harvesting methods to provide substantial shade in his neighborhood. It's not just planting trees, but changing the conditions to support a forest ecosystem.

Water retention has a lot to do with whether water gets absorbed into the ground, and the best way to do this is provide organic matter.

Here is an example, this one from Andrew Millison talking about how the central canal project of Arizona accidentally created a condition that naturally supports a forest along the canal structure. It isn't because the canal leaked, but because the canal forms a berm structure, which then accumulated enough organics to retain the monsoon rains, that then jumpstarted the succession to a forest:

https://www.youtube.com/watch?v=jf8usAesJvo

Water retention also helps to prevent flash floods downstream and reduces the spikes in city water canals.

Property value is typically proportional to tree density.

The US should go on a federally-subsidized, concrete-busting, native tree-planting bonanza.

Also, it should be possible to identify structures with insufficient trees by satellite to offer property owners a suggestion and a partial subsidy.

Don't know, but such cities shouldn't be encouraging urban sprawl, should be insisting for solar panels on every roof possible, and at the same time shouldn't be incentivizing people to move there.

I've lived in AZ, and it is nice in the winter, sure. But that's only a few months. It is hot as fuck in the warmer months and I to this day have no idea why people actually live there. the urban sprawl plus the fact that you have to drive everywhere, just blows my mind.

Arizona is a bit too warm for me, but a lot of people consider driving to be a positive.

I would rather spend 15 mins in my car than 15 mins on a bus. I'd rather live in a place that is sprawling because then everything is bigger - I'd rather have a large house than a small one, a large garden than a small one, and I'd rather shop at a big box store that is more likely to allow me to be hands on with everything I need vs. a teeny high street shop and ordering online.

I currently live somewhere quite urban and barely spend any time in the walkable/public transportable centre because there's not much I want to do there other than pubs and restaurants.

edit: The responses to my post are kind of weird, I'm not telling you to adopt my preferences.

At least where I am 10 mins in a car can be up to 1.7 hours in a bus. And the same back.

If it was an apples to apples comparison then I would rather be driven than drive. But its not.

Take a bike. Might not be 10 minutes, but will be under 30. and cheaper than taking a bus, too.

Bikes are not great. Ebikes might be able to keep up with traffic but not legally. No bike lanes mean your in traffic with posted speeds of 35-40 MPH and actual speeds of 40-48 MPH.

Not to say I disagree with bikes. Ive got all the parts for an ebike just need to mount them. But its not really viable transport around here if you add in the dangers.

Taking a bike when it's 110 F out may be better than walking to a bus stop and then waiting for a bus, but it's still not something that many people want to do...

How does that work if everyone wants that? We don't have enough Earths to support 8 billion people living in sprawl.

We might.

If we have 54 million square kilometers of habitable land that is not used for agriculture, and we scatter 8 billion people across it, then we end up with a population density of about 148 people per square kilometer -- which is approximately what Florida is today.

Do we have the resources to support such a sprawly civilization? It's not just the land, it's all the infrastructure (roads, plumbing, power, etc.) which isn't free.

No, of course not.

But the claim was about the unavailability of space, not of man-made infrastructure.

I said we don't have enough earths to support everyone living in sprawl. That's talking about resources, not just land.

If that is your plan you need teleporters for everybody so you don't need to pave the world to get basic access.

It's not my plan. I was just evaluating one aspect of its practicality. It would be a shitty idea to propose that everyone live in exactly the same way.

Diversity is generally good. It's nice to have some options available.

(Even with universal teleporters, diversity is generally good.)

If the fair distribution is that we have 150 people per square km i.e. approx 6500sqm or 1.5 acres per person, then realistically the answer has to be that some people have a lot more than that and some people have a lot less, because 1.5 acres isn't a large amount of land at all once you get outside of the city.

Does it need to?

Why should everyone live the same way? I know tons of people who prefer city life, and more still who frankly don't really think about it either way.

Surely we all operate this way? My mate goes fishing, if everyone went fishing it doesn't work, but we don't all go fishing.

Reworded:

I love that my car lets me travel alone and without paying the full cost of the miles I log. I'm either terrified of public transit and/or the experiences I've had on it have generally sucked. I prefer bigger everything because I rarely think about the downsides and externalities, and was told from birth that bigger is better. I prefer a large house as long because I can afford somebody else to clean and maintain it, along with the utility bills and property taxes. I prefer a larger garden under the same conditions. I prefer stores that dominate and distort the market and allow me to avoid human interactions.

It would be more polite and useful to ask me to clarify rather than producing a strawman.

I don't prefer driving because it is inexpensive, I prefer it because it has greater utility for me. If the cost of fuel doubled or more I would still do it, I'd just be a bit more efficient with the journeys I do make.

I'm not terrified of the tube/trains/buses, I use them. It's just a bit shit, doesn't go to loads of places I want to go, and is generally less comfortable.

I do think that bigger is better. I don't pay for someone to clean or maintain my house, I do it myself.

I haven't been told that bigger is better, it simply is. For example, just yesterday I made a table. In order to do that I needed enough space to work in and store my tools. I could not do this in a smaller house or apartment.

Theoretically I could hire a workshop or go to a hackspace but that would be substantially more hassle than just walking into my garden or the garage or whatever.

I like human interactions. Just not with endless hordes in a super dense city centre. I prefer chatting with my neighbours, or someone on a hiking trail, or having people over, etc.

It sounds as if you just have different preferences to me. Different hobbies, desires, etc. That's fine, that's why you don't prefer driving. I do.

I live in a small village of 250 people in rural New Mexico, 25 miles from the nearest town. To get to almost anywhere I have to drive. When I socialize, it is mostly with neighbors or people on hiking trails. I have a large set of tools out back and space to use them.

Don't assume that my preferences are so different from yours (though your use of "the tube" suggests that you're located in SE England, so many things may be different).

My point was that all the preferences you expressed come with a cost, not only to you, but to everything and everyone else as well. Talking about these things as if they are merely personal choices is misleading, they are actually personal choices that, in aggregate, shape the world we all get to live in. And the specific set of choices that you listed, for the most part, in aggregate, have a negative impact on the world. I'm a participant in that too, clearly.

I disagree that these things have a negative impact on the world when you or I do them.

I think that if billions of people do them, we have issues, sure.

But there is a finite carrying capacity regardless of what we do.

We could live plugged in like the Matrix and there would still be an upper bound somewhere.

It is patently nonsensical to take the behaviour of one person or even a million people, scale it to 8 billion, and then claim that it's unsustainable as a result.

We have plenty of mechanisms to prevent that from happening. One obvious one is that, as a Brit, I'm legally not permitted to move to the US and live in the same way that someone in Arizona does, which puts a cap on my lifestyle. Most people are in situations like that - ever heard of the "golden billion"?

Kind of amusing, then, that I'm a Brit :)

What brought you all the way from the UK to rural New Mexico?

Nothing like that direct. I've lived in Seattle and Philadelphia before this. The rest of my history is easily discoverable online if you're really interested. Basically, my wife and I really like our house and the region where we live.

I'm curious, do you feel the same for places that reach 40F? 30F? Because heating is a bigger problem than cooling when it comes to contributions towards climate change. Why do I only ever see people railing against people living in hot places, rather than people living in cold places?

It's a lot easier to add heat to survive in a cold place than take away heat in a hot place.

Kinda like how people complain in an office "Can we turn down the thermostat? You can put on a coat but I can't take my skin off".

Additionally, when you add new construction to a hot place, the additional sidewalk and asphalt makes it hotter. Adding new construction to a cold place doesn't make it colder.

I think the point GP was making was that hot daytime temperatures in desert climates tend to coincide with peak renewable energy generation, while at higher latitudes in cloudier places the the source of energy is more likely to be from combustion.

If we're only worried about temperature, sure

But fresh water is a pretty huge concern as well and moving/producing large amounts of that in extremely hot areas is going to more than offset the difference in heating costs

Given the heat pump technology that we have these days, moving heat from A to B is roughly the same as moving it from B to A.

Wet bulb events aren't that simple to deal with. Grid stability doesn't exist in any of the poor and hot equatorial countries. Many people don't even have airtight housing which rules out aircon. If it was too cold instead they could just add clothing and blankets and survive.

Grid stability isn't necessary. It's OK to only run air conditioning when the sun is shining.

There are often blackouts while the sun is shining in lower income countries.

Yes, local solar panels are needed too.

It's cost prohibitive, a small hybrid system costs $4000usd which exceeds the average annual income of many equatorial countries. But you are right that if somehow everyone could install this system (along with an AC and the construction of an airtight room) then wet bulb events would be manageable.

The solar panels to run an air conditioner are a similar cost as the air conditioner.

What difference does it make if heat leaks out or in? The transfer rate is roughly the same.

You can't install aircon into a shack. The cold air will escape.

What happens to heat in a shack?

Its easier, but it isn't more energy efficient, at least not for winters. Average deltaT is smaller when cooling 35 to 25, compared to heating -10 to 20, say.

A problem in cities is that aircos increase outdoor temps, on top of heat from pavement, cars, etc.

There is no way heating isn't more energy efficient than cooling

Heat is even a side effect of cooling, heat is a side effect of basically everything

You’re correct that it is more energy efficient to heat, but the US spends much more energy heating buildings compared to cooling them. As the person you’re responding to pointed out, the difference between cold days and comfortable temperatures is usually much, much higher than the difference between hot days and comfortable temperatures for most people.

That's reasonable

Then again the difference between lethal cold temperatures and comfortable temperatures is also much much bigger than lethal hot temperatures and comfortable temperatures too. EG humans can be pretty comfortable between 32F and 80-90F. The upper limit is pretty much 110F, so only a 20F difference. There's not really any sort of clothing short of some kind of spacesuit with a personal cooling device that can make those temperatures survivable.

Humans can tolerate ridiculously cold temperatures with adequate clothing layers. With clothing you can buy at Walmart you can be pretty comfortable at -40F. With specialized equipment there's basically no limit to how cold the surroundings can be

Not so much with ridiculously hot. Being too hot is just a more complex problem to solve

> the US spends much more energy heating buildings compared to cooling them

I was curious about the stats here:

The latest numbers I can find indicate that the annual US 50-state heating-to-comfort requirement is about 2.5x the cooling-to-comfort requirement. Measured in BTUs.

However: a) These numbers do not account for HVAC energy efficiency (much higher for heating than cooling -- maybe ~90% heat, ~50% cool, so that 2.5x would be closer to 1.5x today) b) Due to warming trends, these numbers have been changing. Was ~3x in 1990, trendlines look like they might converge by the end of the century. With efficiency considered, convergence in about 25 years.

Some obvious unaccounted factors: a) Changes in HVAC fuel or efficiency mix, e.g. heat pumps b) Changes in climate trends c) Migration patterns (more people headed to TX/AZ than AK)

Have a look at how heat pumps work. The difference between cooling and heating is just which end you point inside or outside.

For efficiency it only matter what the delta-T with the outside environment is. Since that is typically lower when cooling than when heating, it is therefore cheaper. Just look at your power bill.

> Have a look at how heat pumps work

Most buildings where I live don't have heat pumps

I mostly only see people railing against living in hot places that are also deserts.

Unlike Arizona, I don't ever see backlash about people living in Mississippi.

I don't really get the problem? Arid conditions are a bit nicer for humans since the wet bulb temps are lower. If it's about water, then agriculture uses a lot more than cities do.

Interestingly enough, I also mostly only see backlash about agriculture in hot places that are also deserts.

Yep. Southwestern states are eventually going to have to decide between their own residents and, e.g., providing year-round lettuce for the rest of the country (Arizona).

The imperial valley - a single farming region in a literal (rather than metaphorical - LA isn't a desert) California desert - uses enough water from the Colorado river to account for 100% of residential water use in California.

30F or 40F ain't bad. My familial roots are in Western NY, where 30F or 40F in the winter is outrageously hot...effectively T-shirt and shorts weather.

People rail against those living in the desert because there's often no water and the water needed to sustain a growing metropolis just isn't available without spending a ton of money and diverting it away from other population centers. Most cold places do have access to water in much larger quantities. (Most, but certainly not all)

Honestly we should all just live in San Diego, where it's never below 65 and never above 85. Perfect weather.

No real issue with installing solar, but the panels are dark. Won't that contribute to the heat island effect, especially considering that among the remediations proposed are white roofs and pavement?

A decade or two ago there was a push to paint as many roofs white as possible, which is why you may intuit dark is bad. Black surfaces convert absorb light energy and convert it into heat. Solar panels do get hot, but part of the point is to turn as much of that light energy as possible into electrical energy.

I much prefer hot af to an icy hellhole. Heating takes up a huge amount of energy and you can’t really do it in an environmentally friendly way unless you get creative. The good thing about the heat is when it’s the hottest, solar panels generate the most energy. It’s a cooling solution that scales itself with the temperature.

> The good thing about the heat is when it’s the hottest, solar panels generate the most energy.

Incorrect. Peak PV efficiency occurs at relatively low temperatures.

Perhaps you mean "when it is hot, there tends to be lots of sunshine, and so there's lot of PV generation" ? That's true of some places (Southern CA, AZ, NV, NM) but less true of others (Louisiana, Alabama, Mississippi, Georgia etc).

> when it’s the hottest, solar panels generate the most energy

That's not true.

> It may seem counterintuitive, but solar panel efficiency is negatively affected by temperature increases. Photovoltaic modules are tested at a temperature of 25° C - about 77° F, and depending on their installed location, heat can reduce output efficiency by 10-25%. As the solar panel's temperature increases, its output current increases exponentially while the voltage output decreases linearly. In fact, voltage reduction is so predictable that it can be used to measure temperature accurately. [0]

> Home solar panels are tested at 25 °C (77 °F), and thus solar panel temperature will generally range between 15 °C and 35 °C during which solar cells will produce at maximum efficiency. However, solar panels can get as hot as 65 °C (149 °F), at which point solar cell efficiency will be hindered. [1]

[0] https://www.greentechrenewables.com/article/how-does-heat-af...

[1] https://www.energysage.com/solar/solar-panel-temperature-ove...

Either ways, if it’s hot there is going to be a lot of uninterrupted sunlight.

It can be hot, cloudy, and humid all at the same time.

Sincerely,

Ohio

Also GA lol

The coldest days around here are the ones where the sky is completely clear.

That doesn't mean that hot days tend to be cloudy.

I live in Phoenix now. My wife and I are planning to move away from here in two years. We were only here because of circumstances outside of our control and now those circumstances are no longer applicable.

Phoenix's main economic driver is real estate development and speculation since the 60s. It has very little in the way of real wealth that serves as a foundation (other than ASU and the two silicon fabs that are there now). A lot of people come here thinking it is affordable cost of living (and it is not that affordable in 2024), but I don't think many residents here really know why they live in Phoenix either.

Best time to get out of a market is before everyone else is running for the door. Lots of stranded assets and sadness ahead for folks who held on to assets too long in the wrong places.

https://www.marketplace.org/2024/05/28/are-we-in-the-midst-o...

http://www.deltaterracapital.com/

One law that passed after the 1994 earthquake in LA was that not only did new construction and remodels have to have all the latest earthquake safety features, but any house sold did too. You couldn't sell a house without doing the earthquake retrofit.

They should pass a similar law with some environmental requirements. The same ones that they are requiring on new construction and retrofits should also be required on sale. That would at least help.

Maybe, but I think the minimum code standards are in general too low.

e.g. I bought a house 2 years ago where they'd replaced all the windows with double pane windows prior to selling. I'd have happily paid the marginal difference to get top-end windows, but now that I've got all new code-compliant windows, it doesn't make sense for me to upgrade them again for at least another decade.

They are passing those laws. As of 2020 all new construction homes sold in California must have a solar system installed. Also in many parts there's strict requirements on what type of landscaping they can have (no grass, only specific plants and drip irrigation allowed).

There's a lot of talk about painting pavement white, but no mention of ripping it out and replacing cars with other forms of transportation. Internal combustion engine vehicles themselves turn 100% of the energy from gasoline into heat, localized to the roads they are driving on. This pumps billions of BTUs of heat directly into a city on a daily basis.[0] We could start cooling these cities down by not unnecessarily heating them up in the first place.

[0] https://www.treehugger.com/cars-add-heat-to-cities-ban-them-...

The rich move to the city, the poor are squeezed out. The poor take long dreaded commutes that make them pay premiums for early/late daycare times and the long commute makes it difficult to find time to look for new jobs.

I make tons of money, I'd do great in your fantastic city. I stopped caring about the lower class last year. Your proposal is fine to me.

Just don't do a bunch of terrible bandaid things that mess up the economy in 20 years because you created a socioeconomic divide.

Because public transportation would be the enemy of the poor?

All our energy usage turns to heat. Best to stay immobile.

Is there any evidence that the heat from cars directly contributes meaningfully to temperature in cities? I’m genuinely curious (but skeptical).

Edit: Some back of the envelope math:

Article says cars add 1.2 * 10^6 BTU of heat per day to Manhattan.

Some rough math on my part suggests that Manhattan gets about 5.6 * 10^11 BTU of heat per day from the sun, 5 orders of magnitude more. The heat directly generated by cars is a rounding error.

I always think it's kind of fun when we're reminded that the sun is literally a huge fusion explosion constantly going off in the sky. Using science to further appreciate the beauty of nature strikes me as very human.

The heat from vehicles isn't distributed spatially across rooftops/walls/trees where the heat might be dispersed; instead the heat from vehicles is concentrated and radiated adjacent to sidewalks (impacting pedestrians) and asphalt (which is effective at storing and re-radiating heat). Nor is it dispersed evenly throughout the day; congestion during rush hour will cause a spike of heat during the hottest part of the day with greater numbers of pedestrians experiencing that heat. Idling vehicles are also running air conditioning, and all of those idling/air conditioned vehicles will be creating an ambient atmosphere where their AC systems will have to run harder to create the same level of cooling.

As you note solar heating likely dominates the overall heating of the city but I would fully expect that idling vehicles contributes meaningfully to the pedestrian and driver perceptions of heat.

BS. Most cars drive on freeways and interstates most of the time, especially the large trucks etc. traffic in residential areas is generally pretty low and it more only during mornings and evenings.

This is just war on cars.

In a lot of US cities, freeways/state highways are where a lot of commercial, retail, and entertainment destinations exist. The first homes usually aren't that far away either, and a lot of apartment complexes are built directly on state highways.

Cars are used only 5% of the time, the rest of the day most of them sit around. They sit around in the sun, heat up and only disperse this heat during the night. Without those massive metal blocks in our streets, instead of large trees, the air could stay cooler during the day and night.

Indeed. And those pesky metal and concrete office buildings sit there empty half the time soaking up heat as well. Not to mention the apartment buildings.

In fact, let's just get rid of the whole city all together. That'll solve the problem.

Not sure how much heat is directly contributed by cars. But regarding the original comment, having dirt or vegetation will be less heat absorbing than even white or gray asphalt. Also it helps with runoff amongst other things.

Even if cars directly aren't contributing all that much, the amount of empty parking spaces likely make their direct surroundings less hospitable than whatever the natural vegetation would contribute.

Do cars cease to exist when they are not driven? No. They sit in a parking space, most likely in the open air where they take away space for trees. Cars is why cities heat up. Put them into expensive parking houses or underground parking to have more surface space for trees.

I'm specifically talking about heat directly generated by cars.

While the raw numbers might suggest that the heat from cars is negligible compared to solar radiation, that overlooks the Urban Heat Island (UHI) effect and the synergistic feedback loops that make urban areas hotter. The UHI effect shows that cities are warmer than their rural surroundings because of concentrated heat sources like cars, buildings, and human activities. This local heat really impacts urban microclimates.

Plus, the heat from cars creates feedback loops. More heat means more use of air conditioning, which releases even more heat exhaust, making the area even hotter. This cycle just keeps adding to the overall heat load in the city. So, even if the direct heat from cars seems minor on its own, it actually plays a significant role in making urban areas warmer.

I'm skeptical of that as well. It's my understanding that the Urban Heat Island effect is from roads and structures lowering albedo and absorbing more solar energy.

https://www.epa.gov/heatislands

https://www.heat.gov/pages/urban-heat-islands

https://www.annualreviews.org/content/journals/10.1146/annur...

A few of these do mention waste energy, but it seems to be a relatively small factor. And of waste energy, I would imagine that cars are themselves a somewhat small factor, compared to electric and natural gas usage.

The UHI effect is mostly down to solar radiation and the thermal mass of the built environment. The sun heats the concrete during the day which radiates heat at night, so that the next day the baseline is higher than the surrounding area. Cars and human activities are a drop in the bucket as a previous poster shows.

If Manhattan is getting 5.6 * 10^11 BTU of free heat energy every day, there isn't much of a reason to import more from outside.

You could lose 4 orders of magnitude to inefficiency and still have plenty to run your cars.

Almost nowhere in the American west has high enough population density to make public transportation very practical.

Sure, you could say "don't live like that". But in practice, that's saying to tear down and rebuild an absolutely massive amount of infrastructure.

On the other hand, if it gets too much hotter, a lot of people might leave, and the rebuilding project would get smaller...

Nonsense. There are multiple clear corridors that public transportation makes perfect sense for. A high-speed rail line from Fort Collins down south through Denver, to Colorado Springs, and potentially as far south as El Paso, seems obvious.

The Utah North-South corridor, as well. A line going from LA-LV-St.George-SLC area also makes enough sense. Not to mention a line connecting Tucson-Phx-Prescott-Las Vegas (potentially going to Reno as well). A Seattle-Portland train makes sense. A whole PCH line makes sense.

I'm not a fan of the high speed rail hype in the US. As another commenter pointed out, many cities are very suburban. So residents would have to drive to train stations just to get on in many cases.

That's ignoring all of the implementation costs, which would likely be extremely high.

Meh. Why should we reduce our quality of life ? We can always use AC in cars and and at home.

> Internal combustion engine vehicles themselves turn 100% of the energy from gasoline into heat, localized to the roads they are driving on.

Let's consider a thought experiment.

We have an ICE car at the bottom of a hill. The car has a trailer attached and there is a weight on the trailer. The mass of the trailer and the weight combined is 500 kg.

The car is started, drives to the top of the hill which is an elevation gain of 100 m, drops off the trailer and weight, and drives back down to the bottom of the hill and is shut off.

The trailer and weight has gained 9.8 m/s^2 x 500 kg x 100 m = 490 000 J of gravitational potential energy, which is not heat.

If all of the energy from the car's gasoline became heat where did that 490 000 J of non-heat energy that the car gave the trailer and weight come from?

100% of the energy becomes heat eventually. For a typical trip, this happens by the trip conclusion. (And also each time the car pauses, such as a stoplight.)

For the trailer-on-hill example, it concludes when the trailer (eventually) is towed or rolls down the hill and comes to a rest from friction.

The weighted trailer is being used like a battery and modifies the situation in the same way as if it were a hybrid car (non-plug-in battery that recharges through regenerative braking and/or directly from the ICE).

If we are going to count energy that is delivered to the payload in a non-heat form that eventually becomes heat then yes, 100% of an ICE's energy from gas goes into heat--but so does 100% of an EV's energy or a bicycle's energy.

The difference between an ICE and an EV with similar sizes and shapes as far as heat goes is that although all the energy from both eventually ends up as heat the EV produces less unnecessary heat. To move the payload a given distance the ICE will use about 4 times as much energy. Only 1/4 of the energy from the gasoline goes toward accomplishing the job of the vehicle. The other 3/4 is waste heat.

That would be sacrilegious to the American identity of requiring driving to do anything.

Have you ever been to the American West? It's nearly all suburban. You would literally have to raze what's there and start over if you wanted to be able to efficiently transport people with public transport.

How much heat to jets generate?

Why would anyone willing trade 2 12 minute drives to and from somewhere, anytime you want, immediately air conditioned, in the privacy and comfort of your own vehicle, with 2 32 minute dirty bus commutes that you have to plan in advance, walk to in the heat, and ride with other people-some of which are homeless.

What a stupid idea.

The stupid idea is believing public transit always implies longer and worse.

In most of the world where residential areas don't need highway-sized roads and you don't need 2 acres of parking lots for a grocery store, you can just walk for most activities.

Destinations are closed enough to your house that you can walk to the park or the bar. For activities that require hauling such as your groceries bikes tend to be enough. And for the people that do require a vehicle such as a work truck, there's so much less traffic on the road that it actually benefits them as well.

The issue is the US is stuck in a local minimum that is way worse than what's possible. They need cars because they build for cars because they need cars.

In reality you could _not_ need cars, because you don't build for cars, because you don't need cars.

The stupid idea is believing it isn't.

You can do the math in any major metro. The buses aren't driving faster than private vehicles. Worse yet, they have no privileges and actually obey traffic laws compared to normal traffic.

For all the years that treehugger readers and their like have espoused the benefits of no cars, it's like they can't do grade school arithmetic. No, it will always take longer to walk to public transportation, wait for the scheduled arrival, and walk to your destination in any existing metro if you don't give them extreme speed limit advantages that also put pedestrians at risk.

Go for it, be my guest, show me a single major metro in this American West as described by the article where you can alter the transit system to make things faster than driving your own private vehicle.

Oh you can't? It's because it's not possible. Oh, just build neighborhoods to not rely on cars from the start? Yeah, OK. Boy, isn't everyone just dying to not only finally own a house, but then own one where you can't drive anywhere and you're subject to the only grocery story in your area, along with everything else you're limited to walking to. What a wet dream for lack of competition.

Stupid idea.

The dumber idea is then these people say, "Well, not everyone needs to own a single-family home."

Hey, and while we're all at it, why don't all of us just own nothing, rely on public transportation, and rent forever. Or better yet, if we're all homeless, we can just have the government pay for everything.

No one talks about these things because they're pointless and add nothing to the conversation.

Worse yet, these people don't even give examples of where their supposed utopia already exists where there isn't an order of magnitude fewer housing units that you can actually own, businesses, or anything else meaningful you want to go to or have in your area.

The supposed answer is always denser housing, renting, and you not owning your own vehicle. Wow what a great standard of living! Sign me up!

Your comment is just very angrily agreeing with me.

Please note the main point of my comment, the US is _stuck_, they dug themselves into a pit where the only option is to dig deeper. That's the whole point!

> The buses aren't driving faster than private vehicles. Worse yet, they have no privileges and actually obey traffic laws compared to normal traffic.

That's because you build public transit that way, it doesn't have to.

> Boy, isn't everyone just dying to not only finally own a house, but then own one where you can't drive anywhere and you're subject to the only grocery story in your area.

You don't need a car, that doesn't mean it's illegal to own a car and drive to the next neighborhood. But since everyone around you doesn't need to get in the road for every little thing there's much less traffic.

> What a wet dream for lack of competition.

Lack of competition... because not having 50 parking spots per grocery store is _obviously_ anti-capitalist...

> Hey, and while we're all at it, why don't all of us just own nothing, rely on public transportation, and rent forever.

I don't know how you turned my comment into an argument against private property.

> Worse yet, these people don't even give examples of where their supposed utopia already exists where there isn't an order of magnitude fewer housing units that you can actually own, businesses, or anything else meaningful you want to go to or have in your area.

Again, I don't know how this is related to home ownership at all. You can still buy properties... And there are examples all around Europe.

> The supposed answer is always denser housing, renting, and you not owning your own vehicle. Wow what a great standard of living! Sign me up!

Again with the property ownership thing... Just buy your car, you can still drive to the corner store if you really want to, they'll just make fun of you.

All this talk about re-zoning, increasing green spaces and limiting sprawl is not helpful. Imho such long-term planning considerations are just a means of delaying action. Cities need things that can be implemented and show results in years, not decades. We must adapt the cities largely as they stand today. Quick solutions are things like painting surfaces white, insulating buildings and connecting spaces via enclosed walkways to minimize loss of AC air. Other options can be more regulatory, such as allowing people to install shades over windows irrespective of local zoning rules.

This article talks a lot about “cool roof” but doesn’t actually tell what it is.

A "cool roof" is a roofing system designed to reflect more sunlight and absorb less heat than a standard roof. Cool roofs are typically made of materials or coatings that have high solar reflectance (the ability to reflect visible, infrared, and ultraviolet wavelengths of sunlight) and high thermal emittance (the ability to radiate absorbed or non-reflected solar energy).

It makes me wonder what is a good roof design for more northern areas - i.e. in Seattle you want “cool roof” in the summer and “hot roof” in the winter.

Nope. You'd just want enough insulation that it didn't make a difference.

https://reasonstobecheerful.world/green-corridors-medellin-c....

plant vegetation.

This is a big problem we are facing in Greece too, especially in our concrete jungle (Athens).

Summers are not just unbearable, but becoming dangerous too.

Extreme weather events are here to stay and we need to find smart ways to handle them. We also need to prepare for a way of life that is different than what we are used to, including the social/economic ramifications of these environmental changes.

There is a bigger problem going on that is still not thoroughly addressed. Heat domes, heavy rain floods, strong winds and other extreme weather effects are becoming more disruptive and frequent, and mitigating just one of the today symptoms without addressing the core problem may be pretty shortsighted.

I find this article extremely ironic and one-dimensional because LA is currently having a record setting year for cold.

As someone convinced by the science of climate change, I’m now increasingly skeptical of how the media portrays its nuance and uncerainty, particularly at the localized and regional level.

It would not surprise me at this point to find out in years’ time that a place like LA cools dramatically because of second and third order effects on precipitation that were not accurately accounted for while the planet overall still warms.

And I think that’s what makes the kind of prescriptivism of this article a bit nauseating.

I’m down to prevent the poor and elderly from dying of heatstroke but I question the rhetoric of this article in the way it is argued.

> I’m down to prevent the poor and elderly from dying of heatstroke

And i also assume from freezing to death?

First hand experience tells me that living outside in a large metro city during the summer was easier than trying to stay warm in the same city during the really cold nights.

I'm not saying it was _enjoyable_ during the summer, but I didn't have the concern of hypothermia during those really cold early mornings.

Come to SF, we're freezing most of the year here.

Those Japanese Air conditioned suits are starting to sound practical.

link?

Space sun shade? https://en.wikipedia.org/wiki/Space_sunshade

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