I’d be interested in hearing from Planet Gore contributors and readers — particularly the number-crunchers among you — on Gil Metcalf’s idea for a revenue-neutral carbon tax: swapping a carbon tax for a reduction in payroll taxes. Metcalf, a Tufts economist and a research associate at the National Bureau of Economic Research, wrote a policy brief on the topic that was co-published by the World Resources Institute and Brookings in August 2007. Some of you may remember that Harvard economist Gregory Mankiw discussed Metcalf’s idea in the New York Times Sunday business section in September.

Al Gore has run up the flag for revenue-neutral carbon taxes, of course. Back in July of 2006, during his jet-setting promotional tour for An Inconvenient Truth, Gore mentioned on Charlie Rose (at or about 42:47) his “personal belief” in a revenue-neutral carbon tax — while stressing the need for a “progressive” approach to its implementation. He returned to the theme on his recent trip to India — how else can you sell carbon reductions to a non-Kyoto country that wants to continue to develop economically? — but came to it only during a question-and-answer period, tellingly.

I realize that some PGers will view a discussion of the most palatable carbon tax as treating the need for one a fait accompli, as an unnecessary surrender. Consider it, then, an academic exercise. Judging by the three presidential candidates we have left, though, some kind of carbon tax is coming: Shouldn’t we try to make sure it does as little damage as possible?