The next phase for people living on the equator likely is to live underground during the day

 As the planet heats up people still need a temperature range where they can survive. Since the earth once you dig down about 1 foot or more underground tends to stay generally around 60 degrees Fahrenheit most places (unless you are very far north or south) digging below ground where the walls of earth will keep you cool. And then if you let the cooler air in during the cooler part of the night and then shut the windows during the day you can stay cool and mostly come out at night when the temperatures are below 100 degrees Fahrenheit. So, living in a cave or underground places you have dug yourself is one way to survive the heat long term worldwide. It isn't that you need air conditioning but it might be nice to have an electric fan you turn on (even if it is solar powered) to blow out the hot air of the day to replace it with the cooler air of the night to early morning.