Climate-neutrality versus carbon-neutrality for aviation biofuel policy

• Global aviation biofuel uptake is modelled under a future emissions trading policy.
• Aviation CO2 emissions are compared with climate impact reductions.
• Climate outcomes are much less favourable than CO2 outcomes for biofuel use.
• Widespread use of aviation biofuel enables carbon- but not climate-neutral growth.

We model global aviation biofuel uptake under a future emissions trading policy, and compare aviation CO2 emission reductions with climate impact reductions (CO2 and non-CO2). We find that climate impacts in terms of global warming potential are less favourable than CO2 climate impacts for biofuel use, dependent on the time horizon of the chosen output climate metric. Results indicate that widespread use of aviation biofuel may lead to a scenario in which aviation growth is accompanied by flat or decreasing carbon emissions but an increasing total climate impact.