Abstract
Navigational contrail avoidance presents an opportunity for rapid reduction in aviation-attributable warming. Here, we use the Aviation Climate and Air Quality Impacts model to evaluate the global temperature changes associated with contrail avoidance towards 2050. If no avoidance is adopted, aviation is projected to contribute 0.040 K of CO2 warming and 0.054 K of contrail warming by 2050. The combined warming from aviation CO2 and contrails is 19% of the difference between current temperatures and the +2 °C limit above pre-Industrial levels, i.e. 19% of our remaining temperature budget. An avoidance strategy phased in over 2035-2045 may recover 9% of this budget, but a 10-year delay may reduce this to 2%. The warming due to additional CO2 emitted during avoidance is two orders of magnitude lower than the expected contrail warming reduction. For every year of delay, the world will be on average 0.003 K hotter in 2050. The most significant climate risk associated with contrail avoidance is therefore inaction.
Data availability
The input aviation data associated with this work has been deposited under accession code https://doi.org/10.5281/zenodo.18245429. The output climate data associated with this work have been deposited under accession codes https://doi.org/10.5281/zenodo.18246901, https://doi.org/10.5281/zenodo.18256701, https://doi.org/10.5281/zenodo.18256763, and https://doi.org/10.5281/zenodo.18256815. Extended versions of the figures in this study are provided in the Supplementary information.
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Acknowledgements
While entirely different in content, the authors of this work collaborated closely with the authors of the Aviation Impact Accelerator’s online report, “The 2030 Sustainable Aviation Goals: Five Years to Chart a New Future for Aviation”, which is available at https://report.aiazero.org/. We would therefore like to thank Robert Miller, Eliot Whittington, Samuel Gabra, Jay Green, Jia Wei Kho and Deepanshu Singh for their continued advice and support.
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This paper was conceptualised by S.R.H.B. S.R.H.B., M.E.J.S., M.L.S., S.D.E., P.J.H., J.M., and M.M. directed the narrative and scope of the paper. The models that feature in this work were derived by J.R.S., P.J.H., M.E.J.S., J.M., C.G., and S.D.E. Climate modelling was completed by C.G., and data visualisation and output analysis were completed by J.R.S. The initial draft of this work was completed by J.R.S. Reviewing and editing was completed by J.R.S., C.G., P.J.H., J.M., M.L.S., M.M., M.E.J.S., S.D.E., and S.R.H.B.
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Smith, J.R., Grobler, C., Hodgson, P.J. et al. The climate opportunities and risks of contrail avoidance. Nat Commun (2026). https://doi.org/10.1038/s41467-026-68784-8
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DOI: https://doi.org/10.1038/s41467-026-68784-8
