The purpose of this paper is to assess and compare regional welfare costs associated with alternative multi-gas strategies for a stabilization of global greenhouse gases (GHG) emissions in the long run. Mitigation costs of non-CO2 greenhouse gases are integrated into a multi-region multi-country CGE model of the world economy. Calibrations are based on GHG emissions projections from, and marginal abatement cost curves provided by, the EMF21 working group for the six greenhouse gases. We find that the introduction of non-CO2 GHGs in the mitigation strategy reduces significantly the welfare cost of a long term emissions stabilization policy but that benefits vary across regions. We also find that the various possible rules of emission quotas allocation may have large effects on the burden sharing among regions.