that policy makers use the available information to make the most efficient decisions
possible with the knowledge available. Independently of the underlying
interpretation of the process of target setting, the policy recommendation from
this group is that for day-to-day project and policy appraisal, it would be relevant
to use marginal abatement cost (MAC) estimates that are consistent with
the existing overall policy goal (the 60% target) as a shadow price for carbon
emissions.