摘要：In the wake of the December 1997 Kyoto Protocol, which, if implemented, would oblige theUnited States and other industrialized countries to reduce greenhouse gases (GHGs) by 2008–2012, anumber of proposals have been offered to increase the incentives for reducing emissions over the nearerterm. The existence of an interim period between setting and implementing environmental goals isubiquitous in environmental policymaking. The existence of this interim period gives rise to severalpotential rationales for early emissions reductions. In this paper we use a series of simple models andnumerical illustrations to analyze some aspects of the performance of early emissions reduction programsin the case of GHGs.We show that there is a compelling economic case for allowing early GHGs reduction credits ifcountries (not just individual firms) could bank early credits to offset future emissions. The annualizedcost savings to the United States from spreading out abatement over time could easily amount to severalbillion dollars. But without the aggregate banking provision, such credits could easily generate anexcessive amount of abatement and produce net economic losses. We analyze a number of other issuesthat affect the economic efficiency of early reduction credits, including asymmetric information, learning-by-doing (LBD), and fiscal impacts. We also compare the performance of an early reduction creditsprogram with that of an early cap-and-trade program. This latter approach, if properly scaled, can avoidmany of the problems associated with early reduction credits.
