Scientists tend to focus on what they don't know more than what they do know. And there are a lot of things we still don't know about the climate. But we know the difference between climate variability and climate change, and right now the amount of carbon in the atmosphere is well outside the variability pattern - and that's quite quantifiable.

We have to fight the terrorists as if there were no rules and preserve our open society as if there were no terrorists.

Many of us who grew up playing golf know that our kids aren't doing it. A great way to enhance the game, make it cool again and bring back some of the interest among younger people is to make golf the greenest sport in an environmental sense. Every course's greenkeeper should think of himself or herself as the greenkeeper: responsible for preserving the green, not just the greens.

Once people get a taste for whatever you want to call it - economic independence, a better lifestyle, and a better life for their children - they grab on to that and don't want to give it up.

Hope and optimism aren't just attitudes, they are life strategies.

I would say that in 2000, we understand as much about how today's system of globalization is going to work as we understood about how the Cold War system was going to work in 1946.

If I were advising President Obama, since he's the one running, I would have made his campaign very simple. I promise that in four years, I will get more Americans, as many as I possibly can, the opportunity and access to some form of post-secondary education. I want more of them to graduate high school with the skill-set of post-secondary education and I want more of them to be able to obtain that post-secondary education. This is the only way we are going to close the income gap.