Avoiding contrails: options for international cooperation

Everyone’s talking about the ‘win-win’ of action on contrails – those white lines in the sky that significantly increase global warming. Our legal paper, produced for the Aviation Environment Federation and others, delves into how states can effectively cooperate to take action on contrails at the international level.  

Background

Aviation has contributed approximately 4% of observed global warming caused by humans to date. This is made up of a combination of CO2 and ‘non-CO2’ pollutants, the most damaging of which is the formation of contrails. Contrails are estimated to cause three times more radiative forcing annually than aviation’s cumulative CO2 emissions.

Contrail avoidance trials are underway internationally, and reports suggest small adjustments to flight plans could produce 15 to 40 times greater climate benefits than the impact of any extra fuel burn. But little action is being taken.

In this paper, produced for the Aviation Environment Federation (working with Breakthrough Energy, the International Council on Clean Transportation (ICCT), Cambridge University, and Imperial College London), we take a deep dive into the components needed for effective international cooperation on environmental issues, and how this can be used to promote action on contrails between states at a regional level.

What’s covered in the report?

Our legal research paper:

• Sets out the key aspects that contribute to the effectiveness of international environmental treaties, and the key provisions for states to consider in any international agreement on contrails.

• Highlights key risks and issues to be addressed.

• Makes recommendations for next steps. Our key recommendation is that as a first step, willing states could consider entering into a non-binding memorandum of understanding to facilitate work and progress on contrails.