Modelling of climate indicators - IMAGE

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Model Documentation - IMAGE

Corresponding documentation
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Model information
Model link
Institution PBL Netherlands Environmental Assessment Agency (PBL), Netherlands,
Solution concept Partial equilibrium (price elastic demand)
Solution method Simulation
Anticipation Simulation modelling framework, without foresight. However, a simplified version of the energy/climate part of the model (called FAIR) can be run prior to running the framework to obtain data for climate policy simulations.

Change in atmospheric gas concentrations also changes the amount of radiation absorbed or transmitted by the atmosphere, and thus changes the earth's energy balance and temperature. The energy balance change is expressed as radiative forcing per gas, measured in W/m2. In MAGICC, concentrations of long-lived greenhouse gases are translated into radiative forcing values using radiative efficiency estimates from the IPCC IMG_Myhre_2013, and radiative forcing of tropospheric ozone is calculated based on ozone sensitivity factors from MAGICC 6.0 IMG_Meinshausen_2011aIMG_Meinshausen_2011b.

However, other processes also lead to changes in the atmospheric energy balance, which are also modelled and assigned a radiative forcing value. Aerosols, such as SO2, NOX, and organic carbon, have a direct cooling effect by reflecting more radiation back into space (direct aerosol effect). They also interact with clouds and precipitation in many ways (indirect aerosol effect); this cloud feedback is the largest source of uncertainty in estimating climate sensitivity IMG_Denman_2007. Although also an aerosol, black carbon has a strong direct warming effect IMG_WMO/UNEP_2011.

Direct and indirect aerosol effects are approximated in MAGICC by scaling the radiative forcing in a reference year (mostly 2005) with the relative increase in future emissions with respect to emissions in the reference year. As MAGICC assumes radiative forcing by albedo and mineral dust to stay constant over the scenario period IMG_Meinshausen_2011a, this is also assumed in IMAGE.