Portugal Abandons Plans for New Airport on Nature Reserve Following Legal Case

Lisbon, Portugal – In a significant development for environmental advocacy, the Portuguese government has officially abandoned plans to construct a new airport on the Tagus Estuary, an internationally protected nature site. This decision follows a protracted legal battle initiated by environmental lawyers and organisations, including ClientEarth, Sociedade Portuguesa para o Estudo das Aves (SPEA, BirdLife Portugal), and eight other Portuguese NGOs.

Legal and Environmental Context

The Tagus Estuary, recognised as Portugal’s most critical wetland, serves as a vital sanctuary for millions of migratory birds. The proposed airport development had sparked widespread national and international opposition from scientists, environmentalists, and the general public. The legal challenge, supported by Portugal’s Public Prosecutor, contended that the Portuguese authorities had inadequately assessed the severe environmental impacts on the estuary’s protected habitats and migratory bird populations before advancing the project.

Soledad Gallego, Head of ClientEarth’s Iberian and Mediterranean office, articulated the environmental community’s relief and rationale behind the legal opposition: “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.”

Strategic Environmental Assessment (SEA) and Alternative Location

In response to the legal action initiated in 2020, the Portuguese government undertook a Strategic Environmental Assessment (SEA) to identify the most suitable location for the new airport. Prime Minister Luis Montenegro’s announcement indicates that the alternative site near Alcochete has been chosen as the result of this comprehensive assessment process.

Despite this relocation, environmental groups continue to express concerns about the broader implications of constructing a new airport. Gallego emphasised the ongoing environmental and climatic considerations: “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. However, 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.”

Legal and Environmental Implications

The case underscores the necessity for rigorous environmental impact assessments in compliance with EU and national laws. The failure to adequately evaluate the environmental repercussions and the assumption that displaced wildlife could simply relocate to nearby habitats represent clear breaches of legal standards protecting biodiversity and ecosystems.

The decision to abandon the Tagus Estuary site reflects a growing recognition within governmental authorities of the intricate balance between developmental projects and environmental conservation. It also highlights the influential role of legal frameworks and public advocacy in shaping sustainable development policies.


The Portuguese government’s shift in airport development plans from the Tagus Estuary to Alcochete represents a pivotal moment in environmental protection and policy compliance. While the alternative location may mitigate some immediate ecological threats, the broader environmental and climate implications of new airport construction remain a critical point of consideration for future infrastructural developments in Portugal and beyond.