Stabilization of atmospheric carbon dioxide via zero emissions—An alternative way to a stable global environment. Part 2: A practical zero-emissions scenario

摘要

Following Part 1, a comparison of CO2-emissions pathways between “zero-emissions stabilization (Z-stabilization)” and traditional stabilization is made under more realistic conditions that take into account the radiative forcings of other greenhouse gases and aerosols with the constraint that the temperature rise must not exceed 2 ℃ above the preindustrial level. It is shown that the findings in Part 1 on the merits of Z-stabilization hold under the more realistic conditions. The results clarify the scientific basis of the policy claim of 50% reduction of the world CO2 emissions by 2050. Since the highest greenhouse gas (GHG) concentration and temperature occur only temporarily in Z-stabilization pathways, we may slightly relax the upper limit of the temperature rise. We can then search for a scenario with larger emissions in the 21st century; such a scenario may have potential for practical application. It is suggested that in this Z-stabilization pathway, larger emissions in the near future may be important from a socioeconomic viewpoint.