Detail on CCSP response surface boundaries
Introduction#When the CO2 levels fall below the lower boundary reported in the CCSP data set for a model, that model's response surface is deemed unable to calculate mitigation costs for that proposal.
Rationale for this approach#In the case of aggressive climate policies, mitigation costs may rise rapidly for even modest incremental additional emission reductions.
Because of this, it could be highly misleading to extrapolate beyond the lower boundary of the CCSP data set.
As a result, a model's response surface does not report a mitigation cost value if a proposal's CO2 levels fall below that lower boundary.
Interpreting absence of mitigation cost value#The absence of a mitigation cost value can mean two possible things:
- Mitigation costs are greater than the values reported in the CCSP study for the Level 1 (450 ppm stabilization) scenario. The attached file "CCSPmitigationcosts.pdf" gives the costs for the CCSP Level 1 scenario.
- The actions outlined by the proposal could be technically unfeasible, since it may not be possible to adopt decarbonization technologies rapidly enough to enable such aggressive emission reductions.
Technical unfeasibility is in a real possibility for proposals that incorporate very aggressive policy prescriptions (e.g. near complete decarbonization of the economy prior to 2050).