1、www.theicct.org communicationstheicct.orgtheicct.org WORKING PAPERJULY 2024Lifetime emissions from aircraft under a net-zero carbon budgetSupraja N.Kumar and Dan RutherfordSUMMARYThe commercial aviation sector is projected to grow rapidly in the coming decades,with an increase in traffic leading to

2、the doubling of the current fleet size and usage of aircraft.Nonetheless,in 2022,airlines and aircraft manufacturers committed to an international goal of achieving net-zero carbon dioxide(CO2)emissions by 2050.This goal was codified by the International Civil Aviation Organization(ICAO)at its 41st

3、Assembly.This study assesses whether current manufacturer delivery projections are consistent with this net-zero target.A net-zero carbon budget of 18.4 billion tonnes was defined for the sector,calculated as an average from four industry decarbonization roadmaps.In this paper,we model lifetime CO2

4、emissions from the 2023 global fleet and new aircraft deliveries through 2042 under three decarbonization scenarios,a business-as-usual(Baseline)scenario and scenarios that include the aggressive implementation of two key mitigation measuressustainable aviation fuels(SAFs;Optimistic SAF)and the use

5、of SAFs and fuel efficiency improvements(Optimistic SAF+Fuel Efficiency).We also consider a sensitivity analysis of more(1.5 C)and less ambitious(2 C)climate targets to contextualize the net-zero budget in terms of warming impact.We find that the 2023 in-service fleet is projected to emit about 9 bi

6、llion tonnes of CO2 before being retired,or almost half of a net-zero carbon budget.Lifetime emissions from new aircraft delivered from 2024 to 2042 are projected to exhaust the balance of a net-zero carbon budget between 2032(Baseline)and 2037(Optimistic SAF+Fuel Efficiency).This indicates that for