Steel and concrete are the most widely-used construction materials around the world, but producing and using them in construction produces high levels of carbon emissions. So how can we build the cities of the future in a more climate-friendly way? In this, using organic materials or recycling and reusing materials are promising approaches. This was the outcome of an international event held by Connective Cities in Potsdam from 13 to 15 November 2023 in partnership with the City of Potsdam as State Capital of Brandenburg, Bauhaus Erde and the Potsdam Institute for Climate Impact Research (PIK).
Around 40 participants from Bhutan, Germany, Indonesia, Nepal, South Africa and Tanzania gave presentations on how they are bringing about the transition to climate-friendly construction in real-life projects. For example, Shanti Ratna Shakya, who is mayor of Banepa in Nepal, described how 70% of the material used to reconstruct the old town was reused. The mayor of Lörrach, Monika Neuhöfer-Avdić reported on plans in her municipality to create Germany’s first wooden-construction climate friendly commercial area.
As is the standard model for Connective Cities dialogue events, the participants from municipal government, business and civil society gave presentations to one another and shared their expertise. They explored specific local project ideas on how to progress climate-friendly construction.
The event in Potsdam concluded with a visit to examples of good practice, such as the wood-built Inselmäuse nursery school and the construction site of a pavilion which is being built with organic and recycled materials, along with a planned multi-function sports hall that is following a hybrid approach.
Prof. Jürgen Kropp from Bauhaus Erde and PIK showed how climate change is affecting cities around the world and causing issues such as increased numbers of hot days. Climate-friendly construction methods using wood and recycled materials could help reduce heat build-up and also reduce carbon emissions from the construction industry, according to Prof. Kropp.
Dr Susanne Winter, who manages the Forests programme for the World Wide Fund for Nature in Germany was joined by Pete Heuer, the chair of Potsdam City Council, to warn against the over-consumption of regrowable raw materials and call for wood used in sustainable construction to come from sustainably managed forests. In this, they argued, we need to find a sustainable balance between protecting and exploiting forests.
In a talk on changing preferences for construction materials in the Hindu Kush region, Erica Udas from the International Centre for Integrated Mountain Development (IDIMOS) in Nepal spoke about the “terrorism of concrete and steel”, particularly in reconstruction following the major earthquake which hit Nepal in 2015. She described how these were displacing traditional sustainable construction methods and generating a large carbon footprint.
Around the world there are innovative ideas for climate-friendly construction, as the projects presented to the event showed.
Banepa in Nepal is rebuilding its historic old town using traditional methods and recycled materials, which calls for well-trained specialists.
The House of Statistics is a model project in the centre of Berlin which is taking a cooperative and community-oriented approach to regeneration into a space for administration, art, culture, social projects, education and affordable housing.
The kingdom of Bhutan is aiming to make careers in construction attractive to young people through innovative sustainable wood construction projects.
The Popo Danes architecture firm in Denpasar in Indonesia is creating modern projects that show how combining traditional and modern technologies can lead to sustainable innovation.
The city of Heidelberg is developing a new urban district on a former military base, with plans to re-use as much as possible of the existing building materials.
Working in partnership with the Potsdam Sustainability Campus, the city of Cape Town is developing a district in which sustainability is the priority for buildings, mobility, environment, businesses and services. For this to succeed, however, it will require a change in mindset for many of those involved.
As part of building a new district on the site of what was previously a military barracks in Munich, the city government aims to use as much existing material as possible.
In Potsdam, experts from planning, builders, manufacturing, technology, politics and administration have developed a memorandum for wooden construction as a basis to simplify the planning and delivery of wooden building projects.
The general tone of the conference was that bringing about a sustainability transformation in the construction industry was not easy, but there were many promising approaches. The first step is to ensure that organic raw materials are available in adequate quantities, such as wood from sustainably managed forests. In many places, participants agreed, this would mean breaking down outdated ways of thinking. Representatives from Asian countries reported that people prefer steel and concrete as modern construction materials and ignore the benefits of materials such as wood. In Germany building codes are planned to make it easier to re-use materials.
Participants also stressed that making the construction industry more sustainable would require forging new alliances and thinking outside the box. Industry, politicians and administrators would need a new business model to make use of regrowable and recyclable materials in construction, based on robust data and analysis. A future scenario of this kind could be developed by sharing examples of good practice and innovative ideas. However, the general public will also need to be convinced of the benefits of more sustainable construction, in addition to introducing new or updating existing legal and policy guidelines.