Now science is warning us that if we do not quickly reduce the global warming pollution that is trapping so much of the heat our planet normally radiates back out of the atmosphere， we are in danger of creating a permanent "carbon summer".
We must quickly mobilize our civilization with the urgency and resolve that has previously been seen only when nations mobilized for war. They were calls upon the courage， generosity and strength of entire peoples， citizens of every class and condition who were ready to stand against the threat once asked to do so.Our enemies in those times calculated that free people would not rise to the challenge；they were， of course， catastrophically wrong.