In the Copenhagen Consensus on Climate 2009, options for climate policy are evaluated and
ranked. The current paper contributes with an analysis of five alternative policies to reduce
carbon dioxide emissions.
Ranking options is a standard tool of decision analysis (Pratt, et al. 1995). It is important to
note that options should be ranked on the basis of an internally consistent set of assumptions.
That is done here for alternative ways to reduce carbon dioxide. By the same token, the
carbon dioxide options presented here cannot be readily compared to the other options for
climate policy presented elsewhere in this forum as they are based on different assumptions
with regard to (1) the future populations, economies, and emissions; (2) the working of the
climate system; (3) the impact of climate change; (4) the impact of emission reduction; and
(5) aggregation over space and time.
