"Let policy follow science: Tie a carbon tax to actual warming"

A very interesting proposal from Ross McKitrick is here.

Excerpts:

...consider the tropical troposphere, the vast atmospheric region centered about 10 miles above the earth, ringing the equator. Climate models project that, if carbon emissions cause warming, the strongest effect will be up there. But both the Intergovernmental Panel on Climate Change and the US Climate Change Science Program (CCSP) have found no significant warming there. A 2006 CCSP report called this a "potentially serious inconsistency" and pointed out that the models with the best fit to the data show low amounts of greenhouse warming. If warming in the tropical troposphere is not soon observed, it will convincingly refute the standard greenhouse warming model.
...
My "T3" formula – short for Temperature of the Tropical Troposphere – guarantees that, if carbon emissions do not cause global warming, the charge will not go up. But if they do cause warming as the IPCC projects, the emissions tax will start rising by between $4 and $24 per ton per decade. The upper-end corresponds to a very aggressive emissions-control scheme. Because the emissions fee would depend on actual warming, the stringency of the policy would depend on the actual, observed severity of the problem.