Lisbon, Aug. 28, 2025 (Lusa) - The environmental association Zero said on Thursday that countries must include all aviation emissions, not just carbon dioxide (CO2), in their climate plans to comply with the Paris Agreement.
"Countries that do not include the non-CO2 effects of aviation are violating their climate obligations," the association said in a statement, in a position supported by a legal analysis carried out by experts in environmental law.
According to Zero, the non-CO2 effects of aviation are estimated to be "at least half of its total climate impact".
"The independent opinion, commissioned by the European Transport and Environment Federation (T&E), of which Zero is a member, and Opportunity Green, shows that countries have a legal obligation to include these emissions in their climate targets (Nationally Determined Contributions - NDCs)," wrote the association According to Zero, these commitments are presented every five years under the United Nations Framework Convention on Climate Change, and the next ones will be announced before COP30, which takes place from 10 November in Belém, Brazil.
The Paris Agreement's temperature-based targets oblige countries to have plans to limit global warming.
"It has been scientifically proven that there are effects unrelated to carbon dioxide emissions from aeroplanes - such as condensation trails, the white lines in the sky left by aeroplanes - that contribute to global warming," the environmentalists emphasised.
These effects, according to Zero, have an impact on the planet "equal to or greater than" those of aviation's CO2 emissions.
"Considering all the effects of aviation on climate plans is a legal imperative. Scientists have been warning about the effect of condensation trails on climate warming for 25 years," the organisation stressed.
"When there is scientific evidence of an environmental risk, even in the face of some uncertainty, a preventative approach should be adopted - which in this case should include measures to deal with the non-CO2 impacts of aviation," the legal opinion, quoted by Zero, states.
The association wants the non-CO2 effects to be included in the next round of national contributions, to be presented before the COP in Brazil.
The European Union should present these targets on behalf of all member states by September 2025, the association reiterated.
The non-CO₂ effects of aviation include nitrogen oxides (NOx), sulphur dioxide (SO2), condensation trails, water vapour and particulates.
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