A growing literature characterizes climate change damages by relating temperature shocks to GDP. But theory does not clearly prescribe estimable forms of this relationship, yielding discretion to researchers and generating potentially considerable model uncertainty.

Many nations have proposed targets for renewable energy production that can only be described as ambitious, given the current levels and the short time frames involved. Proposals in the United States aim to increase renewable electricity production to 15 percent by 2020, a significant amount, given that hydropower capacity is extremely unlikely to expand.