International Industrial Ecology Day 2021

Airline industry CO2 emissions have increased rapidly; air transportation released approximately 2.8% of global fuel-combustion-based CO2 emissions in 2019. Focusing on Japan, this study explored the introduction of new passenger aircraft as a CO2-reduction policy. To this end, the lifetime distribution function for passenger aircraft was specified. Lifecycle CO2 emissions and the associated costs between 1965 and 2019 were then estimated. The results showed that single-aisle aircraft followed a Rayleigh distribution with a mean of 13.42, while twin-aisle aircraft followed a normal distribution with a mean of 19.82. When the average fuel intensity for aircraft inflow improves sufficiently, the reduction in direct CO2 emissions in the flying phase achieved by introducing the early replacement-cycle policy and promoting the introduction of new fuel-efficient aircraft, is larger than the increase in direct and indirect CO2 emissions in the manufacturing phase. Therefore, airlines should introduce an aircraft early-replacement policy to reduce total CO2 emissions if the average fuel intensity for aircraft inflow improves sufficiently. However, comparing the reduced rate of CO2 emissions and the increased rate of cost, the introduction of new aircraft was shown not to be cost-effective as a CO2-reduction policy. From these results, this study concluded that extending the lifetime of single-aisle aircraft and shortening the lifetime of twin-aisle aircraft between 1965 and 2019 was the best option from the perspective of CO2 emissions. However, introducing fuel-efficient aircraft as a CO2-reduction measure is expensive and moreover, the reduction effect is not sufficient. Airline companies need to recognize that strategies to reduce CO2 emissions by only replacing aircraft are costly.