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Marginal Abatement Cost (MAC) Curves

Ranking all abatement options by cost per tonne; visual roadmap.

10 min read · Jacob Willis, Net Zero Lead · Last reviewed July 2026


With many possible measures competing to cut emissions, an organisation needs a way to prioritise. The marginal abatement cost curve ranks the options by cost-effectiveness, revealing where to start and how far each measure goes - a central tool for planning decarbonisation.

In this lesson

  • 01The prioritisation problem
  • 02What a MAC curve shows
  • 03Negative-cost measures
  • 04Reading the curve
  • 05The shape of the curve
  • 06Limitations of MAC curves
  • 07From curve to roadmap
  • 08Sources and further reading