Architects Declare said it will not criticise studios based on individual projects.
"We have a principle of not naming and shaming our colleagues in the industry," the organisation said in a statement. "All practices that have signed the declaration have done so as a public statement that inevitably invites critique."
"We hope that these interactions remain supportive and collaborative as much as possible but we also recognise that the scale and urgency of the challenge will undoubtedly result in difficult conversations and decisions for us all," it continued.
"These discussions are opening up the debate"
Architects Declare was set up last year in response to reports from the United Nations (UN) about the impending climate crisis and threat of biodiversity loss.
Foster + Partners was one of the initial studios to sign up to the declaration in May 2019. The firm has received criticism in the UK national press for designing a terminal building and control tower for a new international airport that will serve the Amaala tourist resort on the coast of the Red Sea.
Architects Declare said that it was glad that a debate over what projects studios should take on was happening.
"There have been vociferous debates in the media and between signatories recently concerning projects which may or may not be considered to be in conflict with the declaration," said Architects Declare.
"While we recognise that every project has a complex social, economic and ecological context beyond what is immediately evident, we are encouraged that these discussions are opening up the debate as to what is considered in keeping with the declaration and a severe emergency situation."
Foster + Partners among first to sign declaration
Practices signed up to Architects Declare to publicly acknowledge the scale of the climate emergency and promise to "design buildings, cities and infrastructures as indivisible components of a larger, constantly regenerating and self-sustaining system".
Alongside Foster + Partners, other founding signatories include Stirling Prize-winning architecture firms Zaha Hadid Architects, David Chipperfield Architects, AL_A, Rogers Stirk Harbour + Partners, and Alison Brooks Architects.
As well as raising awareness about climate change, Architects Declare members pledge to lobby for government funding and to work with clients to find ways of making projects more sustainable. There are now 5,000 practices around the world that have signed up.
Airports "incompatible" with climate goals
In response to the news that Foster + Partners was designing the airport, environment awareness group Architects Climate Action Network (ACAN) said that the studio cannot claim to be prioritising sustainability and simultaneously building new airports.
"Expansion of aviation is simply incompatible with addressing the climate crisis," an ACAN spokesperson told Dezeen.
"There is an urgent need now for us to hold each other to account, particularly on issues so flagrant as the building of new luxury leisure airports in the midst of a climate emergency."
Practices must "live up to the pledges they have made"
ACAN told Dezeen that they are drafting an open letter to Foster + Partners asking them to drop the airport project.
"Foster + Partners are one of the UK's largest and most influential practices, well regarded at home and abroad," an ACAN spokesperson told Dezeen.
"Their actions and inactions will say a great deal about the role and agency of the architect in this climate emergency."
"We don’t feel that the spotlight should be on Architects Declare as an entirely voluntary, unfunded initiative on responding to this issue," it continued. "The onus should be on signatories to live up to the pledges they have made."
Foster + Partners has declined to comment.