"Expanding Portela airport as well as building a new airport would be madness that would put the pedal to the metal on climate chaos through increased greenhouse gas emissions, with harmful effects on the lives of millions of people around the world and in Portugal," they declare in a statement entitled “No to the expansion of aviation, yes to fair mobility.”

Environmentalists argue that the “billions of euros that would be wasted on an airport expansion” should be “invested in a public transport network accessible to all people, including night trains for international travel”.

They point out that greenhouse gas emissions from aviation in Portugal have “more than doubled” in the last 20 years and that Humberto Delgado Airport in Lisbon is “the most polluting infrastructure in the country, with around 15% of total national emissions”.

“In order to meet climate science targets, there can be no expansion of aviation, neither in Portela, nor in Alcochete, nor anywhere else. There must be a reduction in air traffic at all airports,” say the organisations ATERRA, Climáximo, ECOSOC (Ecology and Society Workshop of the Center for Social Studies at the University of Coimbra), Greve Climática Estudantil Lisboa, Linha Vermelha, Morar em Lisboa, Lisboa Possível, Rede para o Decrescimento and XR Portugal.

They emphasise that "expanding aviation would not meet any social needs; it would worsen the climate crisis, the problem of touristification and access to housing, and the quality of life of those living near airports, due to noise and emissions of fine and ultrafine particles."

Lisbon's new international airport, to be built in Alcochete, was presented by the outgoing Prime Minister, Luís Montenegro, in May last year.

ANA, the company responsible for managing airports in Portugal, said it would submit an official application to build the new infrastructure, which is expected to be ready in 2037.