The future does not exist. It is a philosophical concept, until it arrives, at which point it's no longer THE FUTURE. I agree with slowmutant, theorizing about what might happen is counterproductive to what you could be accomplishing right now.
As for the planet and it's human population, don't let the alarmist media scare you into wasting emotional energy on things that aren't going to happen (remember Y2K?). Read Michael Chrichton's State of Fear for a great adventure story, with plenty of footnotes from scientific journals, to put your mind at rest about the global warming MYTH.
Ma Terra is far wiser than we, and has endured far worse than a nest of pesky parasites like the human race. When she's had all she cares to put up with, she'll shake us off like so many fleas. Species go extinct, planets die, stars collapse. Nothing exists forever (at least so far as our the best of puny minds can prove). Enjoy the moment without borrowing trouble from an imaginary 'future'.