Patrick J. Michaels is senior fellow in environmental studies at the Cato Institute and author of Meltdown: The Predictable Distortion of Global Warming by Scientists, Politicians, and the Media, (2004). The last two weeks of July are normally the hottest of the year, so it's no surprise that we're being deluged with public-service announcements about the horrors of global warming. Radio and television stations are compelled to transmit these announcements at no charge because of a long-standing policy that they must provide "public good." "Don't Litter" and "Fasten Seat Belts" come to mind. Now the notion has been expanded to...