Anybody notice the water?
Water Consumption
I noticed, throughout the movie, that there are little odds and ends of scenes showing the people using their water as if it were a normal day. For example, the fountains in New York. When the Admiral, Captain and secretary are dashing from the scene it's easy to see the excessively flowing fountains just outside the building. You'd think that if the world were "on fire" or engulfed in a drastic heat wave that they wouldn't want to try conserving their water in case drastic measures had to be taken.
Now this isn't to say that it wasn't thought over during production, I just think that if everything was ridiculously hot then you'd want to make sure you have enough water in your reserve so that you have a larger percent in the chance of surviving longer.