This paper documents evidence that global climate change target can not beachieved only by Annex countries’ mitigation activities without Non-Annexcountries’ effort and cooperation. I assume there are two countries andnon-perfect competition market. In the result, an Annex country can achieveabatement target, but the emission of a Non-Annex country increases due toits “emission concentration”. So global emission target can’t be achieved. Inother scenario, where Non-Annex country enforces a self-regulation byimposing emission target or invites CDM, global emission can be achieved.But global welfare decreases in the former case. In the last scenario, themixed strategy of self-regulation and CDM, global emission target can beachieved and it has minimum welfare losses.