At the very time we should be reducing all greenhouse gas emissions, aviation emissions are projected to increase rapidly. The International Civil Aviation Organisation (ICAO), the UN specialised agency working with the aviation industry, projects CO2 emissions from international flights will increase 5% a year to 2700 million tonnes by 2050.
International aviation emissions are not covered by the Paris Agreement. The international aviation industry has lobbied successfully for self regulation and in 2015 prevented its emissions from being included in the Paris Agreement and the voluntary pledges of nations to reduce emissions, known as Intentional Nationally Determined Contributions (INDCs ).
The UN International Civil Aviation Organisation’s Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) will allow aviation’s greenhouse gas emissions to continue to grow. International aviation pays no fuel tax, unlike other transports sectors.
No technology, in place or on the horizon, can reduce aviation emissions at the scale and speed required. With unconstrained passenger demand projected to 2050, potential aviation emissions reductions in the near term from existing and proposed technical and operational emissions reduction measures, minimal as they are, will be quickly negated by additional emissions from the overall increase in air traffic.
Flying is the most global warming transport mode per kilometre travelled. Emissions from jet planes high in the atmosphere have a warming effect that dwarfs that from the same amount of fuel burnt on the ground. Unchecked, international aviation emissions will alone drive warming to over 5˚C by 2100.
To restore a safe climate, all future emissions need to drop 6-8% a year to reach zero by 2030, and at least 150 gigatonnes of previous emissions needs to be drawn down. No more carbon can be safely burnt to get warming under 1.5°C even by as late as 2100. Humanity faces an existential crisis not at some time in the future, but right now. We must respond immediately.