I am always a little skeptical on the water thing because I have been hearing that for 30 years, but one year it's going to be true. With the rising populations, Yemen could be the first country in the world, or Sana'a the first major city in the world, to run out of water, that's from Yemeni hydrological engineers and the United Nations. Sooner or later, all of these people, from 7 to 9 billion, all of them want to live like America, will be consuming so much more water that some of the societies will hit a wall without more sustainable environmental practices.

What every employer is looking for is not someone who can do the job, but someone who can reinvent the job.

Pessimists are usually right and optimists are usually wrong but all the great changes have been accomplished by optimists.

Criticizing Israel is not anti-Semitic, and saying so is vile. But singling out Israel for opprobrium and international sanction - out of all proportion to any other party in the Middle East - is anti-Semitic, and not saying so is dishonest.

I don't think that stability and the status quo go together at all, not in a flat world where people are integrated, where women are assuming new roles, where young people want to be consulted and participate. I think the trick is to open up, move down the path of reform, do it in a way that is consistent with your own society's stability and culture, and just don't think you can do nothing.

At the end of the day, no amount of investing, no amount of clean electrons, no amount of energy efficiency will save the natural world if we are not paying attention to it - if we are not paying attention to all the things that nature give us for free: clean air, clean water, breathtaking vistas, mountains for skiing, rivers for fishing, oceans for sailing, sunsets for poets, and landscapes for painters. What good is it to have wind-powered lights to brighten the night if you can't see anything green during the day? Just because we can't sell shares in nature doesn't mean it has no value.

No matter what your profession – doctor, lawyer, architect, accountant – if you are an American, you better be good at the touchy-feely service stuff, because anything that can be digitized can be outsourced to either the smartest or the cheapest producer.