Legal analysis shows that countries that do not include non-CO2 emissions from aviation are breaching their climate obligations. Green groups T&E and Opportunity Green urge countries to do so before this year’s COP in Brazil.
BRUSSELS–(BUSINESS WIRE)–#Aviation–Legal analysis carried out by Cornerstone Barristers concludes that countries must include non-CO2 emissions – which account for at least half of aviation’s climate impact – in their national climate plans to comply with their commitment to the Paris Agreement. The advice, commissioned by green groups T&E and Opportunity Green, shows that countries have a legal obligation to include these kinds of emissions in their Nationally Determined Contributions (NDCs), which they need to submit ahead of COP30 (November 20, Brazil).
The Paris Agreement’s temperature-based targets obligate countries to have plans in place to limit global warming. It has been proven that non-CO2 emissions – like contrails, the white lines in the sky – emitted by planes contribute to this warming. Indeed, scientific research indicates that these effects can rival or even exceed the climate impact of aviation-related CO2 emissions. The legal conclusion is thus that countries that do not include these emissions in their climate plan would be failing in their climate commitments.
Diane Vitry, Aviation Director T&E, says, “Scientists have been warning about the warming caused by contrails for 25 years, now legal advice shows countries must act to reduce them. It’s time to move from paper to action and include the full climate impact of aviation in national climate plans.”
What lawyers say
The legal conclusion is clear: countries are obliged by the Paris Agreement to include non-CO2 emissions from aviation. Three main arguments back this conclusion:
- Temperature based targets – One of the main objectives of the Paris Agreement is to limit temperature rise. Non-CO2 emissions like contrails are known to have a net warming effect, so addressing them is key to countries’ obligation to make ‘ambitious efforts’ to limit the temperature increase to 1.5 °C above pre-industrial levels.
- Reducing the complete bulk of emissions – The Paris Agreement stipulates that the reductions in CO2 emissions must occur simultaneously with reductions in non-CO2 factors, including those caused by aviation.
- Best available scientific knowledge – The Paris Agreement also refers to the need for countries to take action based on ‘the best available scientific knowledge.’ Where there is scientific evidence of an environmental risk, even if there is some uncertainty, a precautionary approach should be taken. An appropriate precautionary approach should include measures to address the non-CO2 impacts of aviation, the legal advice explains.
Avoiding contrails, the low-hanging fruit to reduce aviation’s climate impact
Aviation contributes to global warming by emitting CO2 and currently accounts for around 2-3% of annual global CO2 emissions. But on top of that, aircraft engines emit other gases as well as particulate matter that affect the climate and our health. These are called non-CO2 emissions and are little known despite their huge impact on the environment. The most visible non-CO2 emissions are the so-called contrails, condensation of water vapour from a plane, which warms the planet at least as much as CO2. Contrail warming is a highly concentrated issue — less than 3% of global flights generated 80% of contrail warming in 2019.
However, mitigating these contrails and their effect can be done more quickly and cost-effectively than other climate issues. It would only need a slight change in the route of a small percentage of flights. Moreover, the effects of contrails on the climate are short-lived, so addressing them would deliver short-term climate benefits, very much needed in the race to meet the goals set out in the Paris Agreement.
T&E highlighted that non-CO2 aviation effects must be included in the forthcoming round of NDCs submitted ahead of COP in Brazil, and those countries that have already submitted NDCs should update them to include such effects.
Contacts
T&E
Asia-Pacific Program Director
Jude Lee
[email protected]
