Lyric discussion by toasterhead 

I don't know, my first impression was that "no concerns about the world getting warmer / people thought that they were just being rewarded" meant that people are not taking the earth-threatening problem of global-warming seriously. The way the singer says "now we can swim any day in november" sounds so sarcastic. For these reasons, I think "sleeping in" refers to ignoring the real problems in the world. Those who "sleep in" believe everything as it seems, without looking deeper. Obviously, the ultimate destruction of the earth (reality) outweighs the ability to swim in November (the way it seems)... hence the sarcasm.

@toasterhead i very much agree

An error occured.