Concept of risk-aware contrail avoidance strategies
5 affiliations
- 1Centre National de la Recherche Scientifique (Paris, France)
- 2Institut Pierre-Simon Laplace (Paris, France)
- 3Sorbonne Université (Paris, France)
- 4Institut Pierre-Simon Laplace, Sorbonne Université/CNRS, Paris, France
- 5Department of Meteorology, University of Reading, Reading, UK
Abstract
Targeted contrail avoidance consists of rerouting aircraft to minimise the formation of contrails whose warming of the climate system can be much larger than that due to the CO2 emitted for some of the flights. A commonly proposed strategy is to reroute all flights for which the trade-off between additional CO2 emissions and reduction in contrail warming leads to a climate benefit. However, current predictions of contrail climate impact are highly uncertain. In this study, we describe a framework to integrate the risk of unintentionally damaging the climate in the contrail avoidance decision-making process, using the Contrail Cirrus Prediction model (CoCiP) and operational ensemble weather forecasts. Optimising trajectories around a best estimate of contrail radiative forcing then including weather and parametric uncertainties in that predicted forcing in a second step reveals that 55 % of the reroutings have a higher-than-5 % risk of unintentionally damaging the climate compared to a standard risk-unaware avoidance strategy. This fraction increases to 76 % when choosing to reject any risk. However, the reroutings that are the least risky to operate are also those with the highest potential climate benefit, often referred to as ‘big hits’. Alternatively, accounting for uncertainties from the start of trajectory optimisation allows to mitigate the risk directly when planning the flight. This strategy would even result in a 52 % higher potential climate benefit compared to the risk-unaware avoidance strategy, when choosing to reject any risk. Our results thus demonstrate that the risk of unintentionally damaging the climate can and should be included in the decision-making of contrail avoidance, in particular in the context of early adoption policies.
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BibTeX
@article{borella2026concept,
title = {{Concept of risk-aware contrail avoidance strategies}},
author = {Audran Borella and Cameron Steer and Nicolas Bellouin and Oliviér Boucher},
journal = {Journal of Environmentally Compatible Air Transport System},
year = {2026},
month = jul,
doi = {10.5194/jecats-1-3-2026},
url = {https://doi.org/10.5194/jecats-1-3-2026},
note = {CC BY},
}
RIS
TY - JOUR
TI - Concept of risk-aware contrail avoidance strategies
AU - Audran Borella
AU - Cameron Steer
AU - Nicolas Bellouin
AU - Oliviér Boucher
PY - 2026
DA - 2026/07/10
JO - Journal of Environmentally Compatible Air Transport System
DO - 10.5194/jecats-1-3-2026
UR - https://doi.org/10.5194/jecats-1-3-2026
AB - Targeted contrail avoidance consists of rerouting aircraft to minimise the formation of contrails whose warming of the climate system can be much larger than that due to the CO2 emitted for some of the flights. A commonly proposed strategy is to reroute all flights for which the trade-off between additional CO2 emissions and reduction in contrail warming leads to a climate benefit. However, current predictions of contrail climate impact are highly uncertain. In this study, we describe a framework to integrate the risk of unintentionally damaging the climate in the contrail avoidance decision-making process, using the Contrail Cirrus Prediction model (CoCiP) and operational ensemble weather forecasts. Optimising trajectories around a best estimate of contrail radiative forcing then including weather and parametric uncertainties in that predicted forcing in a second step reveals that 55 % of the reroutings have a higher-than-5 % risk of unintentionally damaging the climate compared to a standard risk-unaware avoidance strategy. This fraction increases to 76 % when choosing to reject any risk. However, the reroutings that are the least risky to operate are also those with the highest potential climate benefit, often referred to as ‘big hits’. Alternatively, accounting for uncertainties from the start of trajectory optimisation allows to mitigate the risk directly when planning the flight. This strategy would even result in a 52 % higher potential climate benefit compared to the risk-unaware avoidance strategy, when choosing to reject any risk. Our results thus demonstrate that the risk of unintentionally damaging the climate can and should be included in the decision-making of contrail avoidance, in particular in the context of early adoption policies.
SN - 3053-9277
ER -