Pritzker Prize-winning architect Norman Foster has criticised architects that have walked away from designing airports due to concerns about the environmental impact of air travel.

Foster, the founder of the UK's largest architecture studio Foster + Partners, defended his decision to work in the aviation sector and suggested that other studios are being hypocritical by not working on airports.

"I do feel passionately that we have to address the infrastructure of mobility," he said. "We have to reduce its carbon footprint, like everything else. We can't walk away from it. We can't adopt a hypocritical moral stance."

"The carbon footprint of air travel is relatively small"

Speaking on Bloomberg TV show Leaders With Lacqua Goes Green, Foster made the comments in defence of his decision to withdraw his studio from environmental group climate change action group Architects Declare last year.

Foster + Partners left the group after it was criticised for working on aviation projects including the Amaala airport in Saudi Arabia.

He told host Francine Lacqua that all infrastructure and forms of travel have a carbon footprint and singling out airports was unfair, claiming that air travel only contributes a small percentage of global carbon emissions.

Most estimates calculate that the aviation industry contributes between two and three per cent of total carbon emissions, although its impact on climate change is increased by other factors, such as the water vapour produced by aircraft, which also contribute to global warming.

"There are those who – I respect their outlook, their views – who walk away and say: 'As a moral principle, we're not going to have anything to do with mobility in the form of travel because it has a carbon footprint'," he said.

"I argue that everything has a carbon footprint. In relative terms, the carbon footprint of air travel is relatively small."

"Imperative to reduce the carbon imprint of transportation"

In the interview, Foster also reiterated his view that his studio has a role to play in reducing the carbon impact of aviation through the design of its airport terminals.

"Air travel is not the journey of a jet across the sky," he said. "Travel mobility in any shape or form is about infrastructure."

"So the buildings that that will move people to a train or to an aircraft consume energy, so there's an imperative to reduce the carbon imprint of transportation of mobility," he continued. "And our society is about mobility."

Foster + Partners withdrew from Architects Declare in December 2020 following tension over its decision to design an airport in Saudi Arabia.

At the time, the group stated that leading architects were "clearly contravening" climate pledges, while climate activist group Architects Climate Action Network called on the studio to withdraw from the project or leave Architects Declare.

Fellow founding signatory to the Architects Declare manifesto Zaha Hadid Architects withdrew from the group a day after Foster + Partners.

"Architects Declare's steering group has unilaterally decided on its own precise and absolute interpretation of the coalition's commitments," said Zaha Hadid Architects at the time.

"By doing so, we believe they are setting the profession up for failure. Redefining these commitments without engagement undermines the coalition and trust."