28 comments

[ 3.0 ms ] story [ 65.5 ms ] thread
Is Anish Kapoor allowed to buy it?

Jokes aside, I can imagine this having tremendous utility in the desert cities or in the warming north during summer.

How much land area would we have to cover with this to solve global warming?
The real question is how much can you fit into the time machine.
According to the article, half of the Sahara Desert based on 2019 calculations. Probably more now.
While that would work as an estimate of total sq meters, applying that scale in a localized area would have too much of an impact on wind/currents, inversion, and the downstream of those changes.

First targets would be urban heat islands and airports. Second would be industrial and manufacturing facilities. Regulations and Nimby would likely mean manufacturing and industrial would be more quick to adapt for use.

The case for urban heat islands is pretty straightforward, but the application with airports would be to mitigate the heat trapping that takes place, especially overnight. Exhaust from flights result in more heat being trapped, similar to urban heat island but due to atmospheric effects and not solely due to surface materials and lack of greenspace.

Imagine a checkerboard of huge tiles dropping the temperature across a large area of desert, for a desert reclamation project.

Seems we are going to have to geoengineer in the future, greening deserts would be a silver lining to all the climate and response chaos.

Call Sherwin Williams (their slogan is cover the world in paint)
https://www.sciencedirect.com/science/article/pii/S036013232...

People are starting to study this. Basically it would be like installing artificial snow to redirect the light energy back to space.

No, it's better than installing artificial snow to reflect energy.

The snow doesn't change the energy budget of the earth at night, because there is nothing for it to reflect, and the infrared energy it emits is pretty much like the infrared energy from most other surfaces, and a certain percentage makes it off planet and the atmosphere absorbs a certain percentage.

The skypaint emits infrared in a particular bandwidth which the atmosphere does not absorb, called the "atmospheric window", so a much higher portion of it's energy makes it off the planet. This effect will operate regardless of whether the sun is shining on it or not, it will keep dumping something around 120 watts per square meter off the planet as long as it is exposed to the sky.

Can we paint the existing snow /ice in the Arctic with this?

Like crop dust with UAV planes? Other than “think of the wildlife/habitat”, why not?

Because the cost would be high, and there would be no quick way to undo it if it turned out to be a bad idea.

And because in the real world you're not allowed to just say "other than all the environmental damage, why not?".

Huge corporations say

“Other than all the environmental damage, why not?” all the time. They weigh the likelihood of being caught or not, and do a cost/benefit analysis. They choose environmental damage just for a 1% increase in profit margins.

If they can do it, why can’t a properly funded radical geoengineering activist group do it?

Because they rule society and activist groups don't? Not sure what you're getting at. Obviously the rules in society aren't applicable to the ruling class, that doesn't change the fact that an activist group would be stopped by intelligence services before doing anything like this. Pointing out hypocrisy unfortunately has no power to stop it.
Probably better off covering building area, to save double, by reducing the need for AC.
I’m curious where the battle between paint and films goes in this new technology area, film is still ahead on total rejected power, which is why ARPA-E funded this: https://arpa-e.energy.gov/technologies/projects/passive-radi...

Film surfaces can be engineered more to withstand dirt accumulation which drops performance, but it may require more skill to apply adhesives on site compared to paint.

In factory, films can be a lot easier to apply due to VOC regulation etc.

Whatever the case, we need this tech deployed.

There’s been some recent success with a diy method. https://hackaday.com/2023/07/03/cooling-paint-you-can-actual...
I followed NightHawkInLight's recipe from youtube, and I've made several batches so far.

I tested the results with an insulated box with an open top covered with glad wrap, and confirmed 11 F less than ambient temp at night, at a variety of humidities. I haven't gotten up early ( or stayed up late ) enough to do a test in the early morning when it's close to 100 percent humidity, but it seems to not be affected by atmospheric humidity, which would confirm it's emitting at that "atmospheric window".

The materials are cheap at scale and the process is probably about as complicated as brewing beer, actually probably less so.

I bought a pack of standard asphalt roofing tiles, so I could paint them and leave them exposed and see how quickly dust, rain and etc degraded the effect. I used the acrylic / acetone / water paint that NightHawkInLight describes, but also tried mixing it with clear coat, and I have a few other cheap and scalable application methods to try.

How did you measure the temperature of the painted material? The saw on this previously (just one yourube video) measured the temperature by using a an infrared temperature device. Which is not the same as the actual surface temperature. The temperature is inferred from the amount of infrared light detected, and the assumed emissivity of the surface. So when the the author concluded that the paint lowered the temperature of the surface by only measuring it with an infrared thermometer, it seemed a flawed conclusion to me. He had only shown that less infrared was emitted than other nearby surfaces, not that the temperature was lower.
Rig up a crop duster and put a coat on Houston, please.
If you add it to the blackest black, will it make the grayest gray?
True neutral grey is actually very, very difficult to produce, so I'd guess that wouldn't work and you'd get some form brown
So true. I love that Gamblin Colors produces their Torrit Grey paint every year from pigment recovered from cleaning the air filters in their warehouse. They say it tends green due to the tinting strength of Phthalo Green. https://gamblincolors.com/torrit-grey/
Where I live in Australia we have very hot summers and cool winters. Sounds perfect to help cool things in summer.

But in winter I don’t want that reflection, I want absorbtion. Any ideas?

I suppose the strategy is to do a calculation for the year, are my summer gains better than my winter losses.

You could focus on insulation instead. The sun rays come in at a shallow angle anyway, so I'm guessing the heating benefit you'd be getting isn't all that large. With insulation on the other hand you have to heat less and keep it inside.
Just paint one side of your roof white and the other black, then flip it over every six months.