Abstract
Marginal abatement cost curves are widely used as an effective means of visualizing trade-offs between emissions reduction and cost. They involve plotting multiple mitigation options on rectangular coordinates, with cumulative abatement as the horizontal axis and specific abatement cost as the vertical axis. The options are arranged in order of ascending specific cost such that, for any given marginal cost threshold, the corresponding cumulative abatement can be readily determined and easily communicated to decision-makers. This approach is very effective for decision support and can potentially be applied to constraints other than cost. In this paper, an extension of this technique is developed for decarbonization measures while considering secondary environmental footprints instead of cost. A case study on six terrestrial Negative Emissions Technologies (NETs) using global sequestration potentials is used to show how trade-offs between climate change mitigation and land or water footprints can be visualized using these Marginal Abatement Footprint (MAF) curves. The results show that targeting an annual negative emission of 8.8 Gt CO2/y requires a MAF of at least 58 Mha/Gt CO2 for land, and at least 1.3 × 10-5 Gt/Gt CO2 for water. Based on the MAF thresholds applied in the study, water is more limiting than land.