Title page
Contents
Summary 4
01. Introduction 6
1.1. What are the impacts of climate change that global society is trying to avoid, and how near are we to that point? 8
1.2. Demand-side measures can be enacted swiftly to buy time for supply-side solutions 9
02. Model overview and summary of high-level results 12
2.1. A starting point: Jet Zero Strategy high-ambition scenario 15
2.2. Impact of COVID-19 on short-term demand 16
2.3. Summary of scenarios, abatement potentials and demand under balanced carbon budgets 17
2.4. Aviation specific carbon budgets 20
03. Supply-side emissions abatement 22
3.1. Fuel efficiency emissions abatement 22
3.2. Zero-emission aircraft 25
3.3. Sustainable aviation fuels 27
3.4. Negative emissions 33
04. Balancing demand management and reliance on future supply-side solutions 39
4.1. Demand management in the near term can buy time for supply-side solutions in the long term 39
4.2. Inclusion of non-CO₂ warming would increase the need for demand reduction 42
4.3. The economic benefits of flying, and the social cost of carbon emissions 43
4.4. Demand-management policy options 47
4.5. What about the aviation sector in other high emitting countries? 54
4.6. Demand in the JZS high-ambition scenario 55
05. Conclusions and recommendations 56
Appendix A1. Current fleet composition 60
Appendix A2. Which aircraft fly each route? 62
Appendix A3. Future aircraft: fuel efficiencies and fleet composition over time 63
Appendix A4. Forecasting demand: route-by-route air traffic movements 66
About the Author 68
Acknowledgments 68
Table 1. Summary of generated aviation decarbonization scenarios 17
Table 2. Aircraft models selected for inclusion in model, based on CAA aircraft type and utilization data from 2019 60
Table 3. Seat classification ranges 61
Table 4. Weighting of each seat class within four route length types 62
Table 5. Assumed fuel efficiencies of future generic aircraft types 64
Figure 1. Low-carbon lifestyles can be classified into avoid, shift and improve options 11
Figure 2. Main modelling components, and how they interconnect 14
Figure 3. JZS high-ambition scenario, abatement of emissions by the main decarbonization mechanisms 15
Figure 4. Global commercial aviation demand, indexed to 2019 levels 16
Figure 5. Summary of UK aviation sector aggregate emissions abatement (2022-50), and maximum demand (PAX-km) to stay within a fair share of global carbon... 18
Figure 6. Emissions abatement across all modelled scenarios 19
Figure 7. Fuel efficiency of commercial aircraft over time 23
Figure 8. Fleet fuel efficiency over time, based on the JZS high-ambition scenario 25
Figure 9. ZEA proportion of all ATMs, once all constraints are applied (range, EIS, production s-curve ramp up) 27
Figure 10. S-curve scale up of global and UK SAF supply, from known current base 30
Figure 11. Proportional split in SAF types over time 31
Figure 12. Life cycle emissions of SAF types, compared to jet fuel 32
Figure 13. Assumed availability of negative emissions 36
Figure 14. Per capita CO₂ emissions from aviation, tourism-adjusted, 2018 54
Figure 15. Retirement profiles of fleet of current aircraft, under four retirement scenarios 63
Figure 16. Fuel efficiencies of all six classes of aircraft, current aircraft and future generic types 65
Figure 17. Rate of fuel burn of the four route length types 66
Boxes
Box 1. What is BECCS? 35
Box 2. The UK aviation sector must consider the risks of relying on negative emissions offsetting 37