In this section we’ve learnt how we model emissions projections and policies to reduce them. Emissions are projected by forecasting land use, consumption intensities and emissions factors. Policies are encoded as modifications to the consumption intensities and/or emissions factors while the land use forecast remains unchanged.
As with all models, this method has its limitations that we must be aware of.
The model is focused on urban emissions that are within the sphere of influence of local governments and so only considers the following sources:
electricity
gas
transport (private, public and active transport).
waste
Additional sources of emissions including agriculture, freight, aviation, industrial processes, fugitive emissions, land use & forestry changes, scope 3 supply chain emissions, embodied emissions, etc. are not considered.
The model considers only macroscopic effects — because we use averages in our assumptions the model is more suited to larger regions with a diverse mix of land uses and activities.
The model ignores circular feedback from interventions — a core assumption of the model is that the interventions do not impact the land use projection. This is for two reasons
the parameters on the interventions should be sufficiently constrained such that they can’t be too drastic
to maintain a consistent frame of reference to compare against
However, it is worth remembering that this model doesn’t contribute to a feasibility analysis and is focused solely on the emissions outcomes.