Interview with Prof. Dr. Thomas Schröpfer about his new book Dense + Green Cities: Architecture as Urban Ecosystem

Thomas Schröpfer’s new book ‘Dense and Green Cities: Architecture as Urban Ecosystem’ propagates two different forms of systems thinking: First is understanding architecture as an urban ecosystem. Second, it recognises the role of green and blue networks, that seamlessly transition our natural environment into our built one.

He is professor of architecture and sustainable design at the Singapore University of Technology and Design (SUTD) since 2011. Before SUTD, he was a professor at Harvard University’s Graduate School of Design. Thomas Schröpfer holds Doctoral and Master’s degrees with Distinction from Harvard University. Since 2015, he is a member of the Core Research Team of the Singapore-ETH Centre Future Cities Laboratory (FCL).

He is the author of numerous publications on architecture and design including Dense+Green Cities: Architecture as Urban Ecosystem (2020), Dense+Green: Innovative Building Types for Sustainable Urban Architecture (2016), Ecological Urban Architecture (2012) and Material Design: Informing Architecture by Materiality (2011).

Professor Schröpfer is the recipient of prestigious awards and recognitions including The European Centre for Architecture Art Design and Urban Studies International Architecture Award; the German Design Award; the Asia Education Leadership Award; and the President*s Design Award, Singapore’s highest honour accorded to designers and designs across all disciplines.

In this conversation with Design City, he talks about his new book and his opinions on sustainable cities development.

Thomas Schröpfer | Front cover.

What factors led to the publication of this book?

The earlier Dense+Green book investigates dense and green strategies at the building scale. One of the research outcomes was the insight that buildings work best in terms of green’ services when they are part of larger urban blue and green systems. In the new book, the research emphasis therefore shifted to the urban scale. I ‘Dense+Green Cities’ shows how buildings can become vertical extensions of urban systems that exist on the ground level. The book investigates how buildings can complement these larger urban blue and green systems by extending them in the vertical dimension.

With increasing urbanisation, how can we leverage ecological infrastructure to help make our cities more resilient?

In my opinion, we need to develop a systems thinking approach to planning and design. The book argues that we should not think of the built environment as collections of individual buildings. Excellent examples for a more integrated approach are the ‘The Interlace’ and ‘Punggol Waterway Terraces I’, both recent large-scale residential developments in Singapore. Both of these projects show that when buildings become part of larger urban blue and green systems, they can e.g. benefit from and contribute to urban biodiversity. As such, they can offer high density that is at the same time sustainable and resilient. As urban planners, designers and architects, we should think of cities as a much more complex and organic entities.

What are the long term paybacks of dense and green buildings?

Our research has shown that facades with greenery typically have significantly lower surface temperatures in the tropical climate than facades without. We illustrate this in the book through thermal images we took of our case studies. This effect of greenery often translates into energy savings in the tropics, where it’s all about keeping the interior spaces cool. The reverse is true in other climates, where e.g. during cold weather facades with greenery can help to maintain the temperature within the buildings through offering additional insulation.
In the larger urban environment, the impact of greenery can also be significant, e.g. it can help to mitigate urban heat island effects.

Were there any unexpected outcomes that came out of the research?

We studied Oasia Hotel Downtown in Singapore, a building that pushes the idea of vertical greening in a spectacular way. Large volumes in this highrise are filled with sky gardens, roof gardens, and the façade is entirely covered with greenery. One would assume that a project like this would make a big difference in terms of local biodiversity. However, the impact on local biodiversity was smaller than what we had expected. This could be due to the fact that Oasia Hotel Downtown does not directly connect to larger urban green and blue networks.
Another somewhat unexpected finding was that the ROI of dense and green buildings was positive. All the buildings we studied benefited from the fact that they featured green components. People were willing to pay higher rents, higher hotel room fees etc. to use them. Therefore it seems clear that economically, dense and green buildings do make sense as well.

Thomas Schröpfer | Exploded isometric, green space.
Patrick Bingham Hall | Ariel view Punggol Waterway Terraces.
Thomas Schröpfer | Exploded isometric, surface temperature.

The discussion around biodiversity in cities is relatively new. How do cities benefit from the presence of biodiversity?

Green and blue systems in the city provide many benefits to people living in the city. One of them is undoubtedly higher levels of biodiversity. This can lead to better resilience and healthier environments for the people living in cities.

Singapore has ambitions of becoming ‘city in nature’ by 2030. Is there a limit to this city-nature interface?

There is a difference between ‘city in a garden’ and ‘city in nature.’ Singapore's 'nature' is in fact highly managed. Interestingly, the official planning paradigm here has recently been changed to ‘city in nature.’ This is an exciting way forward not just for Singapore but potential also for many other cities worldwide.

Has COVID-19 changed the conversation around density and made it necessary to approach it with a fresh perspective? 

Singapore has come through the pandemic fairly well, also due to the fact that it provides a dense and green urban environment in many locations. Buildings which provide shared public and common spaces on multiple levels worked well during the pandemic as they allowed people to be close to nature without the need to travel very far. I believe that density can be designed well or poorly, and ultimately it is a test for planners and designers to get it right. One of the book’s main arguments is that with an increasing urbanisation worldwide, we have to make sure that the resulting density is liveable and that cities are built in a way that they are resilient.

What role can architects and designers play in making the built environment more resilient?

While they have their role, this is a task that cannot just be left to architects and designers. There need to be policies and incentives in place for as many stakeholders as possible so that they have reasons to promote resilient urban environments. Therefore, we have to provide a framework for people to pursue this agenda. Otherwise, it’s not going to happen. We need to demonstrate e.g. to developers that building a dense and green project makes economic sense. We need to demonstrate that a dense and green building attracts more clients than a conventional one, that it can generate higher rents etc., in other words that it makes sense economically. Generally speaking, we have to address the needs of the various stakeholders that are involved.

Thomas Schröpfer | Exploded isometric, surface temperature.

Are there any adverse effects of dense and green buildings? Do dense and green typologies lead to gentrification in cities, and how can we avoid such situations?

In Singapore, WOHA has worked on private residential developments like ‘Newton Suites,’ as well public ones such as ‘Skyville@Dawson.’ Many of the design strategies are the same in both projects. So by no means, at least in the Singapore context, are dense and green approaches limited to high-end developments. Another example of a large public residential project would be ‘Punggol Waterway Terraces I’. We have included many good examples for private as well as public developments in the book.  

Singapore aims to achieve 30% of its food production within its national boundaries. Can dense and green typologies play a role in achieving this goal?

Improving Singapore food security to that extend will require high-tech solutions. Buildings that produce food in large quantities are not necessarily the dense and green buildings we discuss in the book. However, projects like the ‘Khoo Teck Puat Hospital’ include interesting social aspects of urban farming. One of the rooftops of that development features a community garden that is used by the larger neighbourhood, not just by the hospital. Such community involvement comes with many positive social, health etc. impacts.

What’s next for you?

The Singapore-ETH Centre Future Cities Laboratory has just started its new phase called ‘Future Cities Laboratory Global.’ We will continue our work on dense and green cities and shift the focus even more to the urban scale.


Book Details 

Thomas Schröpfer. Dense+Green Cities: Architecture as Urban Ecosystem. 2020. 23 x 30 cm, pages. Birkhäuser. ISBN  978-3-0356-1531-9. DOI