The change in the emission intensity is given in the president's proposal as an 18% decline over the 10 years of the scenario:
base year 2002
scenario year 2012
summvar Emissions
ratio EmissionIntensity
Emissions.by = 100
EmissionIntensity = incr[-18%]
:: GDP >> EmissionIntensity -> Emissions
The expression for the EmissionIntensity variable says that between the base year and
the scenario year, the intensity will increase by -18% (that is, it will decrease by 18%).
