Do you mean backwards in a sense of just backwards, or backwards in a sense that the good guys are the bad guys and people who live are instead the people who die?
I'm going with the former.
The Day After Tomorrow The Day Before Tomorrow:Astronauts look at the earth. New York is Effed, but people are alive and have excessive amounts of helicopters to help them get off the skyscrapers.
Three kids (one wounded) run to a ship INSIDE New York while the ice-covered buildings start melting ground up. Wolves run away from the kids but magically heal the wounded one while doing so. The kids put medicine back into the ship. They then go back to a library.
President Blake ends up coming back to life from the dead, so Raymond gets kicked out of president's Favorite Chair. Someone comes up from the floor and connects his rope to another rope. He is then thrown up and the ceiling of the mall is instantly repaired. The man and another man then start moon-walking in the snow. They eventually come across a car, and drive it through the snow backwards without looking. Then, everyone in the southern US, having taken a vacation in Mexico at the same time, return back to their homes.
Kids run out of a library as water runs away from them. One of the kids mentioned before calls his father. Him and his friends then start trudging in sewer-covered streets. Birds, obviously annoyed due to human neglect, run away from the sewer-covered New York. Then, academic competition!
As a result of the competitions, ice hurricanes spontaneously start going backwards. Astronauts complain about arriving home late. Air traffic is resumed after an undefined length of canceling. Tornadoes in Los Angeles. Oversized-ice Hailstorm in Tokyo. Snow in New Delhi.
A man, after taking a long long time, finally predicts an Ice Age. You think?
Buoys then show water temperatures rising from reforming polar ice. A person then reports things on Global warming. OBVIOUSLY EVERYONE IS NOT CONVINCED DUE TO THE ICESTORMS. Then he goes to the Larsen Ice Shelf and looks at a crack as a person flies up and the crack rebuilds himself. The end.