One day after Architects Declare cofounder Foster + Partners withdrew from the group over criticisms of its airport projects, Zaha Hadid Architects (ZHA) has pulled out as well. Like the former firm, ZHA was one of the original co-signers of an urgent May 2019 letter that declared the profession was in the middle of a climate crisis and couldn’t afford to maintain “business as usual.”

Recognizing that construction accounts for 40 percent of carbon dioxide emissions emitted annually, Architects Declare was intended to be an open-ended working group and commitment for firms to reduce emissions and embodied carbon in their projects and mitigate the ecological damage associated with them. At the time of writing, more than 1,000 U.K.-based firms have signed on to the pledge, and over 6,000 firms have signed on internationally.

Noble goals, but where Foster + Partners and the group parted ways was over their refusal to stop designing airports—while the buildings themselves can be built sustainably, Architects Declare argued that expanding air travel was untenable in meeting carbon budgets.

A week ago, Architects Declare issued an ultimatum to ZHA to either agree to its 11 principles or leave, after principal Patrik Schumacher argued that radical change was a recipe for failure on climate issues, especially if it dampened growth. The organization’s steering group then released a rebuttal, readable here on the Architects’ Journal, calling Schumacher’s comments scientifically incorrect and out of date, and saying that while members are supposed to be self-enforcing, this seemed like an attack on the foundational principles of Architects Declare.

Apart from that, ZHA, like Foster + Partners, has also been involved with a number of recent airport projects, including the 7.5-million-square-foot Beijing Daxing International Airport and Australia’s future largest airport.

Now, December 3, ZHA has chosen to leave Architects Declare. Below is the firm’s full statement on their withdrawal:

Climate change is a defining challenge of our generation and Zaha Hadid Architects (ZHA) is committed to developing solutions.

We embed sustainability into the design, procurement, construction and operations of the projects we are delivering, and we work hard to build integrated client/contractor/design team relationships that can maximise opportunities to improve systems which prioritize environmental issues and ensure cost-effective sustainability.

This collaborative relationship between the client, operator, design team and contractor, together with the development of an overall understanding of the sustainability agenda across the entire project team, is critical to delivering the most sustainable construction and operations of a building throughout its lifetime.

Recent ZHA projects have achieved exemplary accreditation. The KAPSARC research centre in Riyadh and the Generali Tower in Milan were awarded LEED Platinum. The Nürnberg Messe Convention Hall received its Platinum rating from the German Society for Sustainable Building (DGNB) and Leeza SOHO in Beijing obtained LEED Gold.

ZHA is now delivering architecture around the world targeting the highest sustainability certification, including projects in the Middle East, Europe and the Americas planning carbon neutral operations.

We continue this progress; marrying advances in sustainable design and operational systems with innovations in ecologically sound materials and construction practices. We do not look only at the disparate parts, but work to understand them as a whole to deliver effective solutions.

Regrettably we are withdrawing from Architects Declare. As a founding signatory, we agreed to continue and accelerate our work towards progressive change in our built environment. However today we need to recognise that we have a significant difference of opinion with the Architects Declare steering group on how positive change can be delivered.

For us how change is delivered requires discussion, cooperation and collaboration, and this must be debated without condemnation.

Architects Declare’s steering group has unilaterally decided on its own precise and absolute interpretation of the coalition’s commitments. By doing so, we believe they are setting the profession up for failure. Redefining these commitments without engagement undermines the coalition and trust.

We saw Architects Declare as a broad church to raise consciousness on the issues; enabling architectural practices of all sizes to build a coalition for change and help each other find solutions. We need to be progressive, but we see no advantage in positioning the profession to fail. In fact, it would be a historic mistake.