Air conditioners are actually remarkably efficient at what they do, doubly so if used for heating as well. Washing machines are also a lot more efficient than the alternative, that being people manually washing clothes. And commercial airlines don't emit THAT much per capita since most people don't fly all that often.

What the US had during WWI was a lot of domestic manufacturing which is now outsourced and the replacement CO2 emitters are probably mostly cars and animal farming.