Detail on EMF 22 response surface boundaries


Introduction#

When the CO2 levels fall below the lower boundary reported in by a model in its results for the EMF 22 international scnearios, 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 EMF 22 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:

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).

EMF 22 handling of aggressive emission scenarios#

The review article for the internatinal scenarios described how the EMF 22 exercise handled aggressive emission reduction scenarios that could not be modeled.

"All modeling teams participating in the EMF 22 International Scenarios were required to attempt to produce scenarios for all ten climate-action cases. However, no team succeeded in producing scenarios for all ten. Modelers were instructed that they were not required to submit scenarios representing particular climate-action cases if at least one of the following conditions was met:

Leon Clark, Jae Edmonds, Volker Krey, Richard Richels, Steven Rose and Massimo Tavoni. International climate policy architectures: Overview of the EMF 22 International Scenarios. Energy Economics, 31, Supplement 2, (2009): S68.