Biodiversity litigation: Portugal abandons plans for a new airport on a nature reserve after a lawsuit

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INSIGHT by ClientEarth

Environmental lawyers have reacted after the Portuguese government announced it would abandon plans to build Lisbon’s new airport on an internationally protected nature site, following a long-running legal case against it.

Lawyers from ClientEarth and Sociedade Portuguesa para o Estudo das Aves (SPEA, BirdLife Portugal), along with eight Portuguese NGOs, had launched a lawsuit to stop the plans to build the capital’s new airport on the Tagus Estuary, Portugal’s most important wetland and a crucial safe haven for millions of migratory birds.

The plans provoked national and international outcry from scientists and the general public, and the lawsuit received the backing of Portugal’s Public Prosecutor – driving the Portuguese authorities to review and eventually drop the plans. The announcement made by Prime Minister Luis Montenegro means that the Montijo airport on the Tagus Estuary will no longer go ahead – but a new airport will instead be built at an alternative location near Alcochete.


“It is unbelievable that the Portuguese authorities were considering building a new airport on this protected site. The airport would have significantly deteriorated the habitats of this irreplaceable nature reserve and seriously compromised the migratory route from Europe to Africa of birds that depend on this unique area for survival. The decision to abandon building on the Tagus was the only feasible route to take.”

-Head of ClientEarth’s Iberian and Mediterranean office, Soledad Gallego


The groups, who launched their legal action in 2020, argued that the Portuguese authorities failed to properly consider the severe impacts of the future airport on protected migratory birds and habitats found in the Tagus before giving the project the green light.

Failure to fully assess the environmental impact of a project, and jumping to suggesting that birds can and will simply inhabit nearby sites instead, is a clear breach of EU and national laws.

Gallego added: “The authorities have clearly realised that building the airport on this internationally protected site would be incompatible with tackling the biodiversity crisis we are facing. The knock-on effects that this project would have had on migratory birds would have been felt well beyond Portugal’s borders.

“But airports have global climate impacts regardless of where they are built. The Portuguese government should be asking itself whether building a new airport at all is in line with its climate goals and in the best interest of the health of people and nature.”

Following the launch of the groups’ legal action, the Portuguese authorities announced they would carry out a Strategic Environmental Assessment (SEA) to determine the most appropriate location for the new airport. The announcement made by Prime Minister Montenegro to now build the airport near Alcochete is the outcome of the SEA.


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