Their has been a long tradition of Exodus from Earth. It populates Science Fiction in literature and film and NASA have also flirted with the idea. Of the many movies, which featured humans departing a stricken Earth "When Worlds Collide" is a prime example, although, by way of a lottery, only a small fraction of humanity were 'chosen' to leave.
Project SWORD is another example of exodus technology, dreamt up by Gerry Anderson's dream factory. But how much energy would it actually take to take everyone to another planet on an ark or arks?
Well, it would seem to be a lot. This very question was posed to science site "What If". You can check out their answer for yourselves here http://what-if.xkcd.com/7/
What's your favourite Earth exodus/ space ark in books or film readers?
