 Were you to have carbon dioxide, we would have the ice ages back. And were you to double it, we would raise our temperatures by between about 4 and 11 degrees Fahrenheit. Okay, so I have to stop you because we're getting ready for a break. And I need people to know, and we will continue with David Lipsky in just a moment. The Parrot and the Igloo is his brand new book. Climate and Science. Climate and the Science of Denial.