Though Air Con is a big issue and more generally, the increasing heat makes us respond with more energy and so on in a spiral of death, I feel the vast majority of emissions are more industry: A couple of billion cows releasing methane gas daily, for example. The solution? Lab grown meat. Massive coal burning factories, solution? renewables (But even they need a way to transpoort and so on.
Trucks on the road and, even more, shipping indusry which accounts for like 90% of fuel emissions alone (not sure what the exact number is but it's huge).
There's solutions coming for all of them, but... slowwww