International emissions of CO2 are currently no individual country’s responsibility. Aviation and shipping are often grouped together, as facing comparable challenges, but their strengths and weaknesses are really very different. There are lots of opportunities for decarbonising shipping, we can make ships big and slow and use renewables to save energy but it is the shipping industry’s complexity that is its greatest barrier to change. 

In contrast, the aviation industry is more simply structured, but there are few opportunities to reduce emissions because the aircraft are already highly efficient. As a result, the aviation sector relies heavily on emissions trading to deliver cuts in emissions, rather than delivering its own plan. Reducing the demand for aviation by reducing the number of flights or reducing the distance travelled would make a substantial contribution to reducing aviation emissions, and to addressing climate change.