One important element of the current policy debate on what measures should be taken to reduce greenhouse gas emissions is the controversy over the costs of reducing those emissions. "Top-down" macroeconomic and general equilibrium models give much higher estimates of the costs than "bottom-up"...

We analyze the economics of granting temporary exceptions to the phaseout of methyl bromide (MeBr) under the Montreal Protocol on Substances that Deplete the Ozone Layer. The protocol allows such exceptions based on technical or economic "feasibility" through a critical use exemption (CUE)...