Comment by mschuster91
1 day ago
> The good thing about green energy is that one there is a sufficient amount of it, it can also be used for extensive air conditioning.
The heat doesn't vanish with AC, at least not unless you use a very expensive deep-underground well as a heatsink instead of the open air.
Even if everyone has AC indoor - the air outdoor will still be too hot and, most likely, humid, with all the expelled heat from the ACs added on top of that. Animals won't stand a chance, especially wild ones, and humans that absolutely have to work outside (e.g. policemen, firefighters, EMS) will be just as impacted.
We have to face the reality: large parts of the globe, impacting billions of people, will be unable to support human and a lot of animal and plant life during the summer months if climate change continues at the current pace in a short enough time that most people reading this text will eventually witness this.
There's much more air outside than inside, so 15C colder inside does not mean that the entire city gets 15C hotter outside. And in a heat event, most people are inside, not outside. 1C hotter outside to make it livable for 99% of humans sounds fine. And this is only about cities, anything living outside cities will be fully unaffected.
For the people that have to work outside: air conditioning in the vehicle, frequent breaks in air conditioned areas, and I wonder if we could get proper air conditioned clothing at some point (currently vests with fans embedded are quite frequent in Japan, but that's the best there is as of today).
But I agree with the last paragraph. Air conditioning is the only countermeasure we have but in the end the fact remains that many cities will eventually become incompatible with human life in summer.
In a dense residential community, when 70% of the units are running ACs and a minority are not, it's going to get substantially hotter than 1C for the ones that are not. It will be upward of 5C hotter in the non-AC units in my experience when the wind is minimal. The 1C you came up with does not apply in the close proximity of the dense urban air conditioning.
Reflective clothing using PDRC materials will be a lot more feasible than personal air conditioning. The latter would require a powered spacesuit anyway which makes it awkward to work. See https://youtu.be/NVAcSgLZues although it's not about clothing, but the idea is the same.
> Reflective clothing using PDRC materials will be a lot more feasible than personal air conditioning.
Doesn't change the fact that when the wet-bulb temperature (i.e. a combination of the air temperature and humidity) does not allow for evaporative cooling (aka sweating) to work any more. No matter what, you cannot survive such conditions for a prolonged amount of time, as your body will slowly cook itself.
You can survive heat on its own in dry air (that's how people have thrived across MENA deserts, or how people survive saunas), you can survive extensive moisture (that's how people and plants have thrived in the rainforests). But you physically cannot survive in a wet-bulb temperature of > 35 °C for prolonged times.
Tell this to the politicians that make jokes about not putting AC units on schools. This happened on Spain a few days ago.
There's PDRC, but we can't mass produce the "photonic metamaterials" that make it good.
https://en.wikipedia.org/wiki/Passive_daytime_radiative_cool...
It ought to be great. Takes no energy, sends heat through the infrared window back out into space where it came from.
I researched the topic and produced a short video on it: https://youtu.be/NVAcSgLZues
Purdue University produced a barium sulfate nanocomposite paint that has 98% reflectance in the desired band using a 150μm layer, cooling surfaces by 4.5C.
Bollocks. This is more eco-communist propaganda cope from German greens, to justify why their people should keep suffering hot summers living without AC while the other parts of the world and Europe do it just fine.
AC is heat pump like your fridge, it moves the heat from inside to outside, meaning the average between the two sides stays in equilibrium, it doesn't create new heat for the outside to be a measurable impact on the planet's heating. Everyone running refrigerators in their homes to keep the food cold, and transferring that heat to their kitchen, doesn't heat up the cities and planet.
You're also contradicting yourself. If the world is indeed getting fucked heating wise like you say, then at least it will be less fucked if you have AC where you live than trying to live without AC and being more fucked. The planet will not be saved if you give up on having residential AC, you'll just suffer more versus those with AC. So it makes sense form an individaul self preservation perspective.
During the day once the room is cold my minisplit spends around 800w keeping the room cold. Say, what happened to those 800w? Where does that go?
The second law of thermodynamics implies that one must spend energy as work to move thermal energy up a temperature difference. So the net effect of an air conditioner is to increase the total amount of thermal energy.
It's already silly coming from the US, but jumping to the conclusion that a random comment, on a US-based forum, is propaganda specifically for a German political slapfight, is a very funny form of political egocentrism.
it's the Prisoner's Dilemma - AC helps the individual at the expense of those outside, for whom it is now hotter (can raise ambient air temp by 2-4C). It worsens global warming in how it is powered (on hot days might have to fire up peaker plants using gas) and leaks of refrigerants.
Yes but as long as there's no international agreement where we either all stop using AC to "save the planet", then individuals will optimize for their survival and comfort, which means using AC.
You can't force people to downgrade their lifestyle when they see that only applies to them and not to other people on the planet, making their suffering in vain.
> This is more eco-communist propaganda cope from German greens
Strong words coming from someone who's Austrian.
> to justify why their people should keep suffering hot summers living without AC while the other parts of the world and Europe do it just fine.
That was not my point. My point is, ACs aren't a panacea. We cannot let the planet heat up indefinitely because AC has fundamental limits.