There are two kinds of teachers: the kind that fill you with so much quail shot that you can't move, and the kind that just gives you a little prod behind and you jump to the skies.
Look not back. No, not even if you see the dearest and nearest cry. Look not back, but forward. We cannot stop. If we stop we die. We have either to go forward or to go backward. We have either to progress or to degenerate.
Whoever wishes to foresee the future must consult the past; for human events ever resemble those of preceding times. This arises from the fact that they are produced by men who ever have been, and ever shall be, animated by the same passions, and thus they necessarily have the same results.
The shift to a cleaner energy economy wont happen overnight, and it will require tough choices along the way. But the debate is settled. Climate change is a fact.
Global warming, along with the cutting and burning of forests and other critical habitats, is causing the loss of living species at a level comparable to the extinction event that wiped out the dinosaurs 65 million years ago. That event was believed to have been caused by a giant asteroid. This time it is not an asteroid colliding with the Earth and wreaking havoc: it is us.