I'd like to talk to you today about the scale of the scientific effort that goes into making the headlines you see in the paper. Headlines that look like this when they have to do with climate change, and headlines that look like this when they have to do with air quality or smog. They are both two branches of the same field of atmospheric science.

Recently the headlines looked like this when the Intergovernmental Panel on Climate Change, or IPCC, put out their report on the state of understanding of the atmospheric system. That report was written by 620 scientists from 40 countries. They wrote almost a thousand pages on the topic. And all of those pages were reviewed by another 400-plus scientists and reviewers, from 113 countries. It's a big community. It's such a big community, in fact, that our annual gathering is the largest [physical] scientific meeting in the world.

Over 15,000 scientists go to San Francisco every year for that. And every one of those scientists is in a research group, and every research group studies a wide variety of topics. For us at Cambridge, it's as varied as the El Ni