Lynne Kiesling has a joint appointment at Northwestern University in the Economics Department and the Kellogg School of Management, where she studies electricity markets. When the field turned toward environmentalism in the '90s, she found herself drawn into the climate change debate. A self-described "cranky libertarian" and a Pittsburgh native, Kiesling favors a cap-and-trade policy, in which the government creates a market in pollution rights. "For me," she says, "it's not so much about the desk-pounding ideology; it's much more about the utopian vision. I'm a technology optimist. If we just slap a tax on something, what you slap the tax on is going to affect innovation incentives." In "Carbon: Tax, Trade, or Deregulate?" (page 20), Kiesling debates Ronald Bailey and Fred Smith about the right response to climate change.

Ronald Bailey, Reason's longtime science correspondent, has gone from a prominent global warming skeptic to a man who believes some sort of government action—probably a tax on carbon—is necessary to deal with climate change. Why the switch? "I've been following this issue for 20 years," he says, "and finally the science seemed to line up to me." Bailey recently returned from a U.N. conference on climate change in Bali. "For the first time," he says, "I could detect an air of triumphalism on this issue." Perhaps more relevant, "A lot of the climatologists who were there sounded very scared."

Fred L. Smith is founder and president of the Competitive Enterprise Institute, a pro-market think tank in Washington, D.C. Smith, who calls his friend Bailey a "commie symp" on this issue, stands firm in his position that the best thing government can do on global warning—and virtually everything else—is nothing. "Since when," he asks, "did the libertarian movement's goal become to make the cost of intervention in our economy less arduous?" Global warming isn't Smith's only interest: Lately he's been delivering lectures around the country on "the irresponsibility of current modes of corporate social responsibility."