Consider Themodynamics

So heat waves. We've been having a few of 'em since, like... the past several years. Currently there's millions of people throughout the world, even in developed nations, struggling to figure out how to deal with record high temperatures. While my particular locale isn't breaking any records at the moment, it's been pretty toasty for far longer than it used to be when I was a kid. I cast my mind back to my childhood home and its complete lack of air conditioning and wonder how on earth I didn't bake to death in my raised bed on the second story of that place every night during July.

And then I recall that the average temperature at night back then was about 10 degrees lower than it is now. Back then you could get by on just opening your windows at night and closing them during the day, that would keep your house cool enough. Did it get uncomfortable upstairs during the late afternoon? Maybe a little. But nothing so terrible that an AC was required. And then during that one week in July when the average low never dipped below 70 Fahrenheit... well, you just suffered through that. It was only a week.

It's a little different these days, and with people literally dying from heat exposure in places like Oregon (this was last year, it's still relevant) where they've never had to deal with average temperatures near or over 100 for weeks on end but suddenly they had to, it's tempting to look at air conditioning as exactly the sort of preparatory step we should be encouraging everyone to invest in. After all, these heat waves are by all accounts going to just keep happening.

And on the face of it I suppose I agree; having access to AC would have kept some folks from dying. But maybe we should instead be emphasizing better heat education; teaching people how to combat heat with shade, airflow, reduced activity, and increased water consumption. I say that because if you look at AC, it's actually one of the causes of these heat waves. The simple fact is that they aren't 100% efficient (because, like, nothing is 100% efficient), meaning that even when they're powered by completely clean electricity they generate, well, heat.

Let's grossly oversimplify a few topics here as context for the issue. First off, the gross oversimplification of air conditioning. The salient point here is that an AC unit doesn't make cold air. That's not how the physics work. You can generate heat from not-heat by converting something else, like motion via friction or physical materials via some sort of chemical reaction, but you cannot get rid of heat the same way. Once you have heat pretty much all you can do with it is move it around or dissipate it somehow. Rapidly expanding gas from some types of fire extinguishers don't put out the fire because cold, they put it out because the cold sucks up the fires ability to produce heat faster than the fire can produce heat.

Also by smothering it with gasses that can't oxidize. But we're just going to ignore that bit for now.

So what does an AC do to make the inside of your house or your car cold? It takes all the heat inside and dumps it outside. That's it. In technical terms this is called a 'heat pump', and there's one inside basically every appliance that makes a box cold. Your fridge has a heat pump in it; ever notice how while it's running there's a bunch of warm air blowing out from underneath it? That's the heat that was inside the fridge a minute ago. The fridge pumps it out and dumps it into your house, just like your AC takes the heat out of the air in your house and dumps it outside.

Which wouldn't be a problem in an ideal world. That wouldn't make more heat, it would just move the heat around, keeping us cool without making the heat wave worse. Except, like I said, nothing is ever 100% efficient. Your AC has moving components where electricity is converted into the pumping pressure and fan motion needed to move the heat around. These are very efficient processes, but they're not perfect, and so therefore the amount of heat being dumped outside is greater than the amount of heat that was removed from your car.

Grossly oversimplifying, of course.

Now on to the objectively grosser oversimplification of thermodynamics! Specifically we're talking about a sort of lay-person application of the second law of thermodynamics, which has one effect that any closed system will tend toward disorder via a process called entropy. The salient point here is that any effort to impose order on one component of that system will inevitably result in disorder in another part of that system. So effort made to cool a room will result in the space outside of that room growing warmer, until eventually it's no longer possible to cool the room and everything becomes a uniform, hotter temperature than it was before.

Those of you in the know can probably see how I've misapplied that, but explaining why entropy relates to moving heat around is way harder than just making an analogy out of the thing we're talking about.

The point is that if we keep relying on air conditioning to solve our heat wave issues, eventually we won't be able to solve them that way. It's these sorts of things that make global climate change such a bear.

It's okay Laurence, it's not your fault.

The environments have been and will continue to change in ways that are unpredictable and occasionally life-threatening. Trying to solve those issues with our characteristic application of tool use has thus far actually been making everything worse. It's almost as if we need to stop using the tools or apply their use to a novel solution we haven't tried before.

Like space travel.

That's right, as with every other issue I've managed to turn this into a reason for humanity to take to the stars. In this case that's because the vacuum of space is a pretty effective insulator against the damage we've caused to our own biosphere, and would allow us to start over somewhere else using more conscientious tools. Like solar panels.

And swamp coolers.