Solar power is one of the most hopeful technologies but still produces about 0.01 percent of U.S. electricity. The U.S. allocates just $159 million for solar research per year - about what we spend in Iraq every nine hours.

One of the great failings of the American education system (in our view) is that young people can graduate from university without any understanding of poverty at home or abroad.

American airstrikes...create risks, especially if our intelligence there is rusty. The crucial step, and the one we should apply diplomatic pressure to try to achieve, is for Maliki to step back and share power with Sunnis while accepting decentralization of government. If Maliki does all that, it may still be possible to save Iraq. Without that, airstrikes would be a further waste in a land in which we've already squandered far, far too much.

We tie ourselves in knots when we act as if democracy is good for the United States and Israel but not for the Arab world. For far too long, we've treated the Arab world as just an oil field.

Sandy was particularly destructive because it was prevented from moving back out to sea by a "blocking pattern" associated with the jet stream. There's debate about this, but one recent study suggested that melting sea ice in the Arctic may lead to such blocking.

China was probably the worst place in the world to grow up female 100 years ago. There was foot binding, female infanticide, concubinage, and child marriage, and now it's one of the better places. So I really do feel that we're on the right side of history here.

The bulk of the emails tend to come after a column. I can get about 2,000 after a column.