Integrated Assessment of Long-term Climate Policies: Part 2 – Model Results and Uncertainty Analysis

An integrated assessment model (IAM) is applied to explore optionsfor long-term climate policy by identifying permitted emissioncorridors. The options are determined under various assumptionsabout constraints related to acceptable impacts of climate changein terms of alterations induced in natural ecosystems in protectedareas and about acceptable mitigation costs, burden sharingprinciples, and implementation flexibility. The results show thatabout 25% of the protected areas worldwide will witness ecosystemtransformation in the next century even if the costs of emissionreduction are allowed to reach 2% of per-capita consumption. Anuncertainty analysis surveys the implications of modifyingselected key model variables on the existence and shape of theemission corridors. Within plausible ranges of parametervariations, the emission corridor turns out to be rather sensitiveto impact constraints, climatic constraints like the magnitude andrate of the global mean temperature increase, and to aerosolemission scenarios.