Air conditioning is not new. Home cooling efforts date back at least to the Romans in their prime. The Persians made some fairly advanced efforts toward enhancing indoor comfort as well. When out-of-doors, and before air-conditioned vehicles became available, humans adapted their clothing to reduce heat and promote comfort. Dwellers in baking deserts wore robes, to keep the sun off the skin and keep the human under the robes cool. They still do that, of course, in desert lands. In the sweltering tropics, people often chose to wear little or no clothing, with perhaps a broad-brimmed leafy head covering. They still do that, too, in the sweltering tropics.
However we deal with the heat outside, when indoors it is nice to have the place cool. Some of those old Persians did it with pools of water, which made it look cool, at least, and provided some evaporative cooling as well, especially if there was a breeze. To help make sure there was a breeze, those ancients used wind towers to funnel any available stirring air into the buildings. The Romans used water too, by running the water from the famous aqueducts through the walls of their buildings, cooling by heat transfer. It is not a half bad idea, then or now.
Ice is cold, as is snow, and where it was available it was used to cool the people’s drinks, at least, and to cool the room if the frozen stuff could be had in great enough quantities. The Romans had ice and snow brought from the mountains by donkeys in summer. After the train came along, ice could be transported in special railway cars, and was transported as far south as Florida, where it must have been greatly appreciated.
Refrigeration using substances like ammonia and other not too human friendly gases was developed in the eighteen-hundreds. It worked, but leaks could be fatal. In the early twentieth century they figured out how to use chlorofluorocarbon gases in refrigeration and air conditioning. That seemed like a great idea at the time. Much later we saw what we had done to our planet, in the way of damage to the ozone layer which harmed our environment. Now we have advanced refrigerants that do not damage the ozone layer. But we still face the problem of energy use, with the damage done during energy production. We are not home free yet.
In the future we will still want to be cool. Hopefully we will figure out ways to do it without killing off our species in the process. We can consider heat transfer, as the Romans did, possibly tapping the cool seas or deep lakes. Evaporation had a cooling effect on the Persians, and we may well figure out advanced evaporative cooling systems. We have made good progress toward environmentally sound cooling methods. If we keep up the trend, we are quite likely to survive global warming and keep cool as well.