On Earth Day I made a commitment to reduce our emissions of greenhouse gases to 1990 levels by the year 2000. And I asked for a blueprint on how to achieve this goal. In concert with all other nations, we simply must halt global warming. It is a threat to our health, to our ecology, and to our economy. I know that the precise magnitude and patterns of climate change cannot be fully predicted. But global warming clearly is a growing, long-term threat with profound consequences. And make no mistake about it, it will take decades to reverse.

The new energy future is decentralised, entrepreneurial and needs people like you to say 'Give me a clean car, give me solar shingles to put on my roof - give me a clean future'

I figured if I could get really good people who were going to be able to have a big impact in the world over the next decade to come together once a year for ten years and actually sign a pledge to take action themselves, if we did that every year for ten years we could do a lot of good in the world. That's the difference between my meeting and any other. If you don't want to promise to do something, don't come to my meeting, stay home.

President Obama has offered a plan with 4 trillion dollars in debt reduction over a decade, with two and a half dollars of spending reductions for every one dollar of revenue increases, and tight controls on future spending. It's the kind of balanced approach proposed by the bipartisan Simpson-Bowles commission.

Today’s generation of young people holds more power than any generation before it to make a positive impact on the world.

Mental illness is nothing to be ashamed of, but stigma and bias shame us all.

I have said many times-if I hadn't been exposed to music as a child I don't think I would have been president.