This presentation discusses the use and limitations of marginal abatement cost (MAC) curves. MAC curves show the estimated cost of reducing emissions for various technologies and the potential emissions reductions. They are used widely in policymaking but have several shortcomings. Specifically, the assumptions used to calculate costs are often unclear and implementation barriers are not fully captured. When applied to reducing emissions from deforestation and forest degradation (REDD), MAC curves overlook uncertainty in baseline emissions and implementation costs. While MAC curves provide a simple illustration of abatement options, they must be used cautiously, especially in debates around REDD.

1. Marginal abatement cost curves: a call for cautionFabian KesickiUN Climate Change Conference (SB 34) in Bonn, 7th June 2011

2. This presentation is based on the report ‘Marginal Abatement Cost Curves: a Call for Caution’ written by Ekins, P., Kesicki, F. and A. SmithA research article of the same name is forthcoming in Climate Policy.2

3. Concept of Marginal Abatement Cost (MAC) Curves

4. Policy Use of MAC curves

5. Shortcomings

6. MAC Curves and REDD (Reducing Emissions from Deforestation and Forest Degradation) OVERVIEW3

7. MAC CURVE CONCEPTElectric heat pumpGas CCSElectric boilerCoal CCSBiomassSolar PVSolar CSPGeothermal Offshore windEfficiency improvementOnshore windCars plug-in Nuclear Cars full hybridResidential appliancesInsulation retrofitResidential electronics4

8. POLICY USE OF MAC CURVEMany areas:

9. Electricity saving

10. Air pollution

11. Waste reduction

12. Water availability