Overview of mitigation scenarios for global climate stabilization based on new IPCC emission scenarios (SRES)

Abstract

This paper provides an overview of new emission mitigation scenarios that lead to stabilization of atmospheric CO₂ concentrations, presented in this Special Issue. All of these scenarios use as their baselines the new IPCC scenarios published in the IPCC Special Report on Emission Scenarios (SRES), which quantify a wide range of future worlds. This means the new mitigation and stabilization scenarios are based on a range of future development paths that have fundamental implications for future emissions reduction strategies. Here, we refer to these new scenarios as “Post-SRES” mitigation scenarios. In addition to providing an overview of these new scenarios, this paper also assesses the implications that emerge from a range of alternative development baselines for technology and policy measures for reducing future emissions and stabilizing atmospheric CO₂ concentrations. Nine modeling teams have participated in this joint effort to quantify a wide range of mitigation and stabilization scenarios. The nine modeling approaches involve different methodologies, data, regional aggregations and other salient characteristics. This pluralism of approaches and alternative baselines serves to cover some of the uncertainties embedded across a range of different mitigation and stabilization strategies. At the same time, several common trends and characteristics can be observed across the set of Post-SRES scenarios. First, the different baseline “worlds” described in the SRES scenarios require different technology/policy measures to stabilize atmospheric CO₂ concentrations at the same level. Second, no one single measure will be sufficient for the timely development, adoption and diffusion of mitigation options to achieve stabilization. Third, the level of technology/policy measures in the beginning of the 21st century that would be needed to achieve stabilization would be significantly affected by the choice of development path over next one hundred years. And finally, several “robust policy options” across the different worlds are identified for achieving stabilizations.