Al Gore

"As human beings, we are vulnerable to confusing the unprecedented with the improbable. In our everyday experience, if something has never happened before, we are generally safe in assuming it is not going to happen in the future, but the exceptions can kill you and climate change is one of those exceptions."

"I have faith in the United States and our ability to make good decisions based on the facts."

"I think the cost of energy will come down when we make this transition to renewable energy."

"I took the initiative in moving forward a whole range of initiatives that have proven to be important to our country's economic growth, environmental protection, improvements in our educational system."

"If we don't succeed, we run the risk of failure."

"Our world faces a true planetary emergency. I know the phrase sounds shrill, and I know it's a challenge to the moral imagination."

"Science has a culture that is inherently cautious and that is normally not a bad thing. You could even say conservative, because of the peer review process and because the scientific method prizes uncertainty and penalises anyone who goes out on any sort of a limb that is not held in place by abundant and well-documented evidence."

"While President Bush likes to project an image of strength and courage, the real truth is that in the presence of his large financial contributors, he is a moral coward."