Whats the difference between the United Nations emissions scenarios and what Pielke et al. found?
Pielke et al. found that “two thirds or more of all the energy efficiency improvements and decarbonization of energy supply required to stabilize greenhouse gases is already built into the reference scenarios.” This means that the IPCC, and most other analyses of climate policy, assume that a large portion of the decarbonization of the global energy supply will occur automatically, that is with out policy interventions. “If much of these advances occur spontaneously,” Pielke et al. explain, “as suggested by the scenarios used by the IPCC, then the challenge of stabilization might be less complicated and costly.
