TY - JOUR

T1 - Rank-order concordance among conflicting emissions estimates for informing flight choice

AU - Kaivanto, Kim

AU - Zhang, Peng

N1 - This is the author’s version of a work that was accepted for publication in Transportation Research Part D: Transport and Environment. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Transportation Research Part D: Transport and Environment, 50, 2017 DOI: 10.1016/j.trd.2016.10.037

PY - 2017/1

Y1 - 2017/1

N2 - Abstract Air transport Greenhouse Gas (GHG) emissions estimates differ greatly, depending on the calculation method employed. Among the IPCC, ICAO, DEFRA, and BrighterPlanet calculation methods, the largest estimate may be up to 4.5 times larger than the smallest. Such heterogeneity -– and ambiguity over the true estimate -– confuses the consumer, undermining the credibility of emissions estimates in general. Consequently, GHG emissions estimates do not currently appear on the front page of flight search-engine results. Even where there are differences between alternative flights’ emissions, this information is unavailable to consumers at the point of choice. When external considerations rule out alternative travel-modes, the relative ranking of flight options’ GHG emissions is sufficient to inform consumers’ decision making. Whereas widespread agreement on a gold standard remains elusive, the present study shows that the principal GHG emissions calculation methods produce consistent rankings within specific route-structure classes. Hence, for many consumers, the flight identified as most GHG efficient is not sensitive to the specific calculation method employed. But unless GHG emissions information is displayed at the point of decision, it cannot enter into consumers’ decision making. A credible and ambiguity-free alternative would thus be to display GHG ranking information on the front page of flight search-engine results.

AB - Abstract Air transport Greenhouse Gas (GHG) emissions estimates differ greatly, depending on the calculation method employed. Among the IPCC, ICAO, DEFRA, and BrighterPlanet calculation methods, the largest estimate may be up to 4.5 times larger than the smallest. Such heterogeneity -– and ambiguity over the true estimate -– confuses the consumer, undermining the credibility of emissions estimates in general. Consequently, GHG emissions estimates do not currently appear on the front page of flight search-engine results. Even where there are differences between alternative flights’ emissions, this information is unavailable to consumers at the point of choice. When external considerations rule out alternative travel-modes, the relative ranking of flight options’ GHG emissions is sufficient to inform consumers’ decision making. Whereas widespread agreement on a gold standard remains elusive, the present study shows that the principal GHG emissions calculation methods produce consistent rankings within specific route-structure classes. Hence, for many consumers, the flight identified as most GHG efficient is not sensitive to the specific calculation method employed. But unless GHG emissions information is displayed at the point of decision, it cannot enter into consumers’ decision making. A credible and ambiguity-free alternative would thus be to display GHG ranking information on the front page of flight search-engine results.

KW - Greenhouse gas emissions

KW - Carbon footprint computation

KW - Scheduled passenger air transport

KW - Informed choice

KW - Decision making

KW - Behavior

KW - Policy

U2 - 10.1016/j.trd.2016.10.037

DO - 10.1016/j.trd.2016.10.037

M3 - Journal article

VL - 50

SP - 418

EP - 430

JO - Transportation Research Part D: Transport and Environment

JF - Transportation Research Part D: Transport and Environment

SN - 1361-9209

ER -