Unless we stop dumping 70 million tons of global warming pollution into the atmosphere every 24 hours, which we are doing right now ... the continued acceleration of this pollution would destroy the future of human civilization.

The truth is that climate change is presenting the greatest challenge humanity has ever faced.

As president, I will bring all the parties and stakeholders together. I am going to come up with a solution that respects the environment and does not cause an upheaval in the economy.

Today I challenge our nation to commit to producing 100 percent of our electricity from renewable energy and truly clean carbon-free sources within 10 years.

I've learned the importance of changing people's minds at the grassroots level so that whoever does run will have a much better chance of encountering public opinion that reaches a critical mass and brings about a change not only in White House policies but in the Congress and in the state legislatures and all around the world.

What changed in the United States with Hurricane Katrina was a feeling that we have entered a period of consequences.

Every nation has a moral obligation to safeguard the future.