Imagine how much carbon would not be spewed into the atmosphere if we just got rid of the Olympics. Let alone all the wasted energy building facilities that usually just end up rotting after the event is over.
NYS (Lake Placid) got grief for housing athletes in facilities that were built for use as a prison after the games.
On the other hand, lots of American athletes got grief for deciding forego the Brazilian accommodations, and stay on a cruise ship docked during the games. Didn't really pay attention to the games, so I don't know how many other nationalities also declined the local hospitality.