Al Gore’s An Inconvenient Truth has been criticized for not offering enough ideas to solve global warming. But his documentary has not only far exceeded box office expectations, grossing three times the early estimates already; it has also brought in waves of new ideas from well-known thinkers in a variety of fields.

As long as global warming was thought to be a murky scientific controversy, so-called opinion leaders could safely ignore the subject. But now that — as science reporter Eugene Linden remarked in an interview a couple of months ago — “the naysayers and deniers are starting to look more and more like idiots,” the experts are scrambling for unclaimed ground on which to plant their flag and show their smarts.

Just in the last couple of weeks, the Constitutional law professor Cass Sunstein at the University of Chicago has pointed out that Dick Cheney’s “One Percent Doctrine” is a virtual endorsement of the Precautionary Principle much beloved by enviros concerned about global warming; the well-known sociologist Robert Putnam [$] compared the difficulty people have accepting the fact of global warming with the difficulty they have accepting loneliness in America; and Dan Gilbert, a psychologist, came up with a instant classic of a line, “if only gay sex caused global warming.” (For discussion, see this post.)

Now economist Joseph Stiglitz, who once chaired President Clinton’s Council of Economic Advisors, has thrown in his two cents. Stiglitz sees Kyoto as an important first step, but given that the U.S., the world’s largest carbon emitter by far, has not signed on, he rationally thinks the agreement needs “an enforcement mechanism.”

As he says in his piece, entitled “A New Agenda for Global Warming“:

If the United States could go its own merry way–keeping the carbon dioxide it emits over its own territory, warming up its own atmosphere, bearing itself whatever costs (including hurricanes) that result, that would be one thing. But that is not so. The energy profligate lifestyle of the United States inflicts global damage immensely greater than any war it might wage. The Maldives will within 50 years be our own 21st century Atlantis, disappearing beneath the ocean; a third of Bangladesh will be submerged, and with that country’s poor people crowded closer together, incomes already close to subsistence level will be further submerged.

But instead of revising the Kyoto Protocol, or calling for a new treaty, Stiglitz argues that other nations should use a well-established existing international agreement — the World Trade Organization — to pressure the U.S. to change its ways.

In most of the developed countries of the world today, firms are paying the cost of pollution to the global environment, in the form of taxes imposed on coal, oil, and gas. but American firms are being subsidized–and massively so. There is a simple remedy: other countries should prohibit the important of American goods produce using energy intensive technologies, or, at the very least, impose a high tax on them, to offset the subsidy that those goods are currently receiving.

Stiglitz points out that the United States, a big backer of the WTO, has already recognized its right to regulate for environmental reasons, because the U.S. refused to allow importation of Thai shrimp caught in “turtle-unfriendly” nets.

He does admit that this policy might not be popular with everyone:

Of course, the Bush Administration and the oil companies to which it is beholden will be upset. They may even suggest that this is the beginning of a global trade war. It is not. It is simply pointing out the obvious: American firms have long had an unfair trade advantage because of their cheap energy, but while they get the benefit, the world is paying the price through global warming. This situation is, or at least should be, totally unacceptable. Energy tariffs would simply restore balance–and at the same time provide strong incentives for the United States to do what it should have been doing all along.

Stiglitz also has ideas on how to bring developing nations into line, but he begins with the biggest problem: the United States. Some might not like the regulatory thrust of his plan, but a carbon tax, which it implies, is hardly a new or radical proposal. Those wild-haired radicals at The Economist proposed it eight years ago.

And you can’t call Stiglitz a crazy hippie, either, given that he was a senior fellow at the right-leaning Hoover Institution, has served as chief economist at the World Bank, and has won the Nobel Prize.