How science-based strategy, city policy, and system-wide sobriety can reshape sustainability leadership
At Earth Action, we collaborate with experts who don’t just talk about systems change. They drive it. Denis Bochatay is one of them. An environmental engineer and co-founder of Bieler & Bochatay, Denis has spent over two decades working at the interface of science, infrastructure, and environmental policy.
Today, as Climate Project Manager for the City of Lausanne, he’s focused on translating global climate goals into practical action on the ground. This means integrating mitigation and adaptation into municipal policy. As an external expert with Earth Action, Denis brings that same systems mindset and pragmatism to corporate and institutional strategies.
We sat down with Denis to explore his take on today’s environmental priorities, the underestimated potential of sobriety, and the uncomfortable but necessary truths facing sustainability professionals and businesses alike.
Local action, global stakes
Denis’s current work centers on coordinating Lausanne’s climate strategy. That means embedding climate science into long-term decision-making across energy, mobility, buildings, and infrastructure.
“The work is challenging, not just because of the complexity, but because the city has real levers to act. I find purpose in using scientific data to inform and influence decisions. It’s what helps an organization truly move toward a sustainable future.”
But for Denis, climate work isn’t only about emissions or infrastructure. It’s about equity. As one of Switzerland’s largest cities, Lausanne has a duty to lead, he says.
“In a wealthy country, our responsibility is also about solidarity. By showing what’s possible here, we can help shift norms and expectations globally (especially for communities with fewer resources).”
Facing the facts: Efficiency, not illusions
Denis is clear-eyed about the obstacles. While many businesses and policymakers focus on new technologies to solve the climate crisis, he argues the real untapped potential lies elsewhere: in efficiency and sobriety.
“We’re racing ahead with new tech when often, solutions already exist. The problem is, they require us to reduce, not add. That’s a harder sell.”
Take emissions from wastewater treatment. Thanks to recent research by EAWAG, it’s now understood that nitrous oxide emissions from treatment plants are significantly underreported. In Lausanne, Denis notes, the city’s own plant is now recognized as the second largest territorial emitter of greenhouse gases.
“It’s never fun to uncover more emissions. But in this case, we can act. Technical solutions exist. It’s far easier to address than asking people to stop over-consuming.”
Are consumers still part of the solution?
For years, sustainability narratives have leaned heavily on consumer responsibility. Denis, though, is less convinced.
“The world has become too complex for individual consumers to judge. Even with my background, I sometimes can’t tell which product is best. We need policy. Decisions must be based on science, not disinformation.”
That doesn’t mean businesses are off the hook. But it does mean they must stop waiting for consumer demand and instead anticipate regulatory shifts, investor pressure, and systemic change.
Metrics that matter
As a former life cycle assessment (LCA) student and practitioner, Denis is well aware of the complexity of environmental indicators. But when asked what matters most for business decision-making today, he’s unambiguous:
“You have to measure GHG emissions. The climate crisis is the biggest driver of interconnected impacts. When fossil fuels are phased out, you’ll see reductions in transport, marine impacts, pollution. It’s all linked.”
Still, he cautions against falling into the trap of reporting without action.
“Measurement is just the start. What matters is using that data to decide differently.”
Advice for leaders and businesses
So, what should organizations do now, especially those struggling to reconcile long-term sustainability with short-term pressures?
Denis suggests three core principles:
- Focus on what already works
Don’t default to innovation when solutions exist in policy, efficiency, or design. - Think beyond products
Challenge whether a solution truly adds value or just adds waste (connected toothbrushes, he notes, are a perfect example). - Stay grounded in impact
Don’t chase visibility. Focus on actual environmental performance and let the credibility follow.
Closing the gap between science and strategy
At Earth Action, Denis contributes his operational insight and systemic perspective to projects involving environmental metrics, transition planning, and long-term strategy design. His work reflects our core values: aligning ambition with scientific integrity and turning complex challenges into structured, scalable responses.
“Climate strategy isn’t about having all the answers. It’s about asking better questions and being willing to act on what the data tells you.
From municipal buildings to corporate boardrooms, Denis Bochatay helps decision-makers do just that.
