In this paper we present some numerical simulations with the MacGEM model to evaluate the consequences for the Kyoto Protocol on the reduction of greenhouse gases of the recent Bonn agreement and the nonratification by the USA. MacGEM is a global marginal abatement cost model for carbon emissions from fossil fuel use. Marginal abatement cost functions are estimated on data generated with the GEM-E3-World general equilibrium model under the assumption that abatement is produced in a cost efficient way in every individual country/region of the model. Nonparticipation of the USA causes the equilibrium carbon price in Annex B countries to fall by approximately 50% since an important share of permit demand falls out and the global abatement objective is substantially eroded. With respect to the Bonn agreement, we focus on the Commitment Period Reserve (CPR) and carbon sinks. The CPR is a compliance mechanism requiring all Parties to maintain some fixed number of permits on their permit account. It entails a binding permit export ceiling for the former Soviet Union and central European countries. It raises the equilibrium carbon permit price by approximately 30% and generates substantial monopoly rents for permit exporters. Finally, carbon sinks enhancement activities are accounted for by assuming that they represent free abatement options. These activities enable Parties to fulfil their reduction commitment at lower compliance costs and cause the equilibrium permit price to decreases even further. We conclude that the Bonn agreement has indeed eroded completely the Kyoto Protocol's emission targets but that it has the merit to have saved the international climate change negotiation framework.
