Smart Cap

Policymakers'imperfect knowledge about firms' abatement costs leads to inefficient regulation, reducing the welfare gains from carbon markets around the world. We introduce a "smart" cap and trade system that eliminates these costs. This cap responds endogenously to technology or macroeconomic shocks, relying on the market price of certificates to aggregate information. It allows policy makers to modify existing institutions to achieve more efficient emissions reductions. The paper also shows that the slow diffusion of technology innovations typically makes the optimal carbon price a much steeper function of emissions than suggested by the Social Cost of Carbon.