Can cities ever be truly sustainable?
This time I sat down with Andreas Qvist Secher, an experienced sustainability expert and founder of Urban Upstream, to dive deep into what “urban sustainability” really means today. I had met Andreas a few years ago, but this was our first chance to record a proper conversation about his work — one that bridges the gap between city planning, climate strategy, and applied science.
From big consultancy to independent impact
After working with climate policy and City of Copenhagen and urban sustainability at a global firm Ramboll, Andreas lately launched his own consultancy exploring the question:
How can I make real impact — and on what level?
At Ramboll, his work had evolved toward research and applied science, where he could translate findings into practical actions. He also co-supervised industrial PhD projects, helping young researchers navigate between academia, public policy, and private-sector needs.
“For me, it was about figuring out how to turn science-based insights into new actions.”
That same curiosity drives Urban Upstream today. Andreas’s current work explores how urban planning can move from projecting to doing — how cities can turn data, science, and sustainability reports into actual transformation.
Defining what sustainability means today
When I asked Andreas to define sustainability, he smiled. It’s a term that’s easy to say but hard to pin down.
“In discourse theory, sustainability is what’s called an empty signifier — a word you can fill with whatever meaning you want.”
For him, the meaning of sustainability has changed dramatically over the last decade. What once meant energy efficiency or cycling infrastructure has expanded to include regeneration, planetary boundaries, and global responsibility. “Everybody agrees it’s a good thing, but it depends on the definition you put in it.”
He pointed to frameworks such as the doughnut economy and the concept of planetary boundaries, which connect local urban planning decisions to global impacts. “When we plan urban districts, all the upstream or embodied impacts — the materials, the imports, the way we shape cities — are actually some of the biggest we have,” he noted.
For Andreas, true urban sustainability isn’t just about reducing consumption; it’s about transforming cities to improve both environmental performance and quality of life. It’s about asking, “How do we live well within limits?”
The framework: update, upgrade, uphold
At Urban Upstream, Andreas developed a simple framework — update, upgrade, uphold — to guide cities toward that transformation.
1) update our ways of working - sustainability knowledge changes fast, so applied science and continuous learning are crucial. This means refreshing methods, questioning assumptions, and bringing new data into planning.
2) upgrade refers to improving existing systems rather than adding new ones. “Upgrading doesn’t mean doing more,” he said. “It means doing better with what we have.” For example, cities can rethink how they use existing buildings, streets, and infrastructure to serve changing social and environmental needs.
3) uphold emphasizes long-term commitment — maintaining the progress achieved and embedding it in policy and governance. “Sustainability is not a project with an end date. It’s something you have to uphold.”
This framework recognizes the complex network of stakeholders that shape cities — from investors and policymakers to engineers, designers, and citizens — all operating within layers of responsibility and influence.
Understanding urban metabolism
To grasp how cities consume and regenerate resources, Andreas draws on the idea of urban metabolism — treating cities as living organisms. “We’re building these big organisms every day, but we rarely look at their metabolism — what we’re putting in and what comes out.”
With urbanization accelerating globally, the scale is shocking: every week, the world builds the equivalent of Paris in new floor space. This relentless expansion, he argued, has enormous environmental consequences. “Business as usual will not live up to the Paris Agreement,”.
Urban metabolism helps link life-cycle thinking to urban design, combining technical analysis with social goals. The aim is not just efficient buildings, but cities that enable a “good life” without overconsumption.
Andreas also reminded me that most new construction is happening in the Global South, not Europe or North America. “We have an obligation to help each other — north and south, east and west. The environmental burden of new buildings is immense, and we need global collaboration.”
The “stop building” movement and planetary limits
This topic led naturally to the Stop Building movement — a growing debate in Denmark’s architectural scene advocated for among many by architects like Søren Nielsen and Nicolai Bo-Andersen. They argue that the Global North has built enough, and that we should now focus on retrofitting and reuse instead of new construction.
They joined my podcast some months ago, so you can listen to our conversation here:
Andreas also cited research by Lise Hvid Horup, a PhD student he co-supervised, who examined how much new construction fits within planetary boundaries. “Her research showed that, at most, we can allow 20 percent new build,” he explained. “That means 80 percent of what we currently plan should not be built if we want to stay within environmental limits.” This finding raises difficult ethical and political questions: Who decides what gets built? How are budgets allocated? And what kind of progress do we value?
Andreas agrees that building less and retrofitting more are crucial but insists this shift must go hand-in-hand with new ways of thinking about urban life. “It’s not just about retrofitting. That also comes with a cost. It’s about changing our mindset — how we live in cities that consume so many resources and emit so much CO₂.” He believes municipalities, citizens, and the building industry must collaborate on a shared vision that balances local needs with global responsibility.
Balancing local needs and global responsibility
For Andreas, this tension between the local and the global sits at the heart of sustainability. “That’s the beautiful thing about it. There are so many dimensions — but also so many frictions.” He distinguishes between ‘need-to’ and ‘nice-to’ functions: some things cities truly require, others are simply desirable. Sustainable planning must recognize that difference while keeping an eye on the long-term legacy. “We have to think about what we’re putting in front of future generations. Once, legacy meant education or philosophy — now it must also mean leaving behind a livable planet.”He believes that planners and designers should reintroduce the idea of legacy thinking into the sustainability conversation. “We can’t just focus on the next two or four years. We need to think in a future context — what kind of world are we leaving behind?”
The role of certification in urban transformation
Given his years of involvement with the Danish Green Building Council (DK-GBC), I asked Andreas about the role of certification systems such as DGNB. Can they actually drive transformation, or are they simply a marketing tool — “a sticker on the wall”?
Andreas admitted he shared that skepticism when he first faced certification schemes more than a decade ago. But over time, he’s come to see their potential to structure dialogue and create a shared language around sustainability. “Certification gave me a way to talk about the different dimensions of sustainability,” he said. “It helps identify local potentials and dilemmas — if used correctly.”
The DGNB Urban District framework, originally developed in Germany, assesses projects across the environmental, social, and economic pillars of sustainability. “It’s not the certification itself that matters, but how you handle it and how you engage the stakeholders involved.”
“Sustainability isn’t a checklist — it’s a mindset shift.”
From new builds to transformation
Andreas is particularly encouraged by recent changes in certification practice. In Germany, DGNB is piloting new guidelines for existing urban districts, focusing on transformation and optimization rather than just certifying new developments. “There’s no such thing as a final product in urbanism. Cities are constantly transforming — and certification needs to reflect that reality.”
This shift mirrors the global conversation about adaptive reuse and regenerative urbanism. Certification can act as a bridge between research and practice, translating scientific insight into parameters that policymakers, developers, and architects can work with.
“If developed the right way, certification can transform new research insights into measurable actions. It creates the evidence-based groundwork that helps push the sustainability agenda.”
He recalled that lifecycle assessment and CO₂ accounting only entered Danish building legislation because certification schemes first made them measurable. “Ten years ago, we wouldn’t be where we are today without that,”. For him, the real power of certification lies in its ability to test and refine — to push practice toward the next “state of the art,” then test again.
From knowledge to action
At the end, I asked Andreas how to make sure that knowledge from research actually reaches projects — especially when clients say sustainable solutions are “too expensive”? He admitted that this is one of the biggest challenges. “Ten months in, my main focus has been on research partnerships,” he said. “Bringing together existing knowledge and figuring out how to apply it across the industry.”He hasn’t yet faced direct pushback, but he understands the dilemma. “There are always two dimensions — cost and context. Everything we do in the built environment today has a negative impact unless we truly operate within a regenerative framework. And that’s very tough.”
He believes the key is focusing effort where it makes the most difference. “We always have to look at what are the local benefits versus the global impact,” he said. “Sometimes that means choosing projects or approaches that deliver greater overall value, even if they’re not the easiest.”
To conclude: sustainability isn’t about perfection — it’s about progress through informed choices.
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