One twisted thing about cooling and climate change: It’s all a vicious cycle. As temperatures rise, the need for cooling technologies increases. In turn, more fossil-fuel power plants are firing up to meet that demand, turning up the temperature of the planet in the process.
“Cooling degree days” are one measure of the need for additional cooling. Basically, you take a preset baseline temperature and figure out how much the temperature exceeds it. Say the baseline (above which you’d likely need to flip on a cooling device) is 21 °C (70 °F). If the average temperature for a day is 26 °C, that’s five cooling degree days on a single day. Repeat that every day for a month, and you wind up with 150 cooling degree days.
I’m not sure “cooling degree days” are a good way to measure environmental impact. They neither represent the amount of heat pumped into the atmosphere (as the energy per degree depends on several factors such as mass and heat capacity of the cooled stuff) nor the amount of electricity used (as different A/C’s have wildly different degrees of efficiency) nor the amount of CO2 released (as that depends on how the electricity has been produced).
The power hunger of AI has already been mentioned, so I’m not going to repeat that point, though IMHO it’s by far the bigger issue than residential cooling.
Having said that, if you’re worried about the enviromental impact of your home, the power consumption of a reasonably efficient A/C can easily be offset by just a couple of medium-sized solar panels. Of course both the solar panels and the efficient A/C cost money that not everybody can afford to (or cares to) spend, so you’d have to take cheap and inefficient A/C’s off the market, thus effectively making chilled air a privilege that only the rich can afford. That’d probably lead to lots of heat strokes and other health problems amongst low-income families, so you’d have to weigh the environmental impact of inefficient A/C’s against another rich/poor gap.