“The elephant in the climate room”

When Philipp Misselwitz talks about the future of construction, he's virtually unstoppable. "I'm a desperate optimist," says the head of the "Bauhaus Earth" organisation, which researches how sustainable construction can protect the environment instead of damaging it. In an interview with What Next, the professor at the Technical University of Berlin discusses why the number of buildings worldwide will double, why so many myths about wood and other materials persist so stubbornly and why using cutting-edge technology has to take into account the overall ecological balance.

The vision Bauhaus Earth has is that the construction sector should not only do less harm; it could even become a healing force for nature.

Above all, we must understand construction holistically, across its entire life cycle: from the cultivation and extraction of building materials to the act of building itself, to how we can flexibly use buildings over time, and the question of what happens if something eventually has to be demolished. If we succeed in this, we will have enough levers to pull.

We need a materials transition. Until now, mineral and fossil materials like steel and cement have dominated. It won't be possible to do without them entirely in the future, but there are many bio- and geo-based alternatives – from wood to clay and earth, to fungi or agricultural waste products like straw. These are abundant in nature – and in many cases, they can regrow. This can cover a large part of future demand.

Current prices are distorted because the negative effects of using concrete are not factored in. We need a level playing field, where all cost factors are considered. We are far from that. However, the choice of building materials alone is not enough for the construction industry to drive a real turnaround in the fight against climate change.

We can reach a point where the construction industry can counter climate change, protecting the planet instead of damaging it.

We need to use materials more efficiently and less wastefully, and here too, this applies along the entire value chain, from the very beginning. A forest, for example, is a complex ecosystem, and only those who truly understand it can plant trees in a way that benefits the planet, encourages biodiversity and prevents forest fires. Material usage can also be optimised during construction itself. And last but not least, when it comes to converting or deconstructing buildings. This is a major topic in Germany and Europe, and the economy is only just starting to adapt to it. There is now a whole array of start-ups that are working intensively on how to build a circular economy in the construction sector.

Myths and prejudices persist very stubbornly. For example, many still believe that wood poses a high fire risk.

In a best-case scenario, cities will become carbon sinks because – instead of emitting it in industrial processes – we will store CO₂ in durable, nature-based building products. At the same time, we will reforest new areas that, in turn, remove CO₂from the atmosphere. If everything aligns, we can reach a point where the construction industry can actually counter climate change, protecting the planet instead of damaging it.

It can help at all stages of the value chain. AI can help to better understand the complexity of nature, develop waste-free building products, use them optimally and ultimately protect the planet. However, we must always keep the overall ecological balance in mind: if today's state-of-the-art building technology reduces heating and cooling costs but consumes a lot of energy during its production and perhaps becomes obsolete and needs to be replaced after only a few years, then nothing would be gained in terms of tackling climate change.

Things are moving, but not fast enough and not broadly enough. There are pioneers in all areas, among developers and investors as well as among construction companies and material suppliers. We need to communicate these examples better and make them so well known that they become driving forces. Scalability is still lacking.

The situation is incredibly serious. But we must not allow ourselves to be paralysed or become numb to it.

In the 20th century, buildings made of steel, glass and concrete became a symbol of modernity and prosperity for many people. A certain social perception of materials emerged: those who are poor build with what is readily available, such as wood and clay; those who can afford it build with concrete – even if these buildings often bring new disadvantages like mould.

Indeed, myths and prejudices persist very stubbornly. For example, many still believe that wood poses a high fire risk. However, it has long been scientifically proven that wooden buildings are easier for firefighters to extinguish than steel ones, because steel bends after only a short time. So we need to educate more in this area.

We need more research in the field of sustainable construction. As long as concrete and steel are the predominant materials for companies, they will invest most in them. That’s why foundations and government funding programmes are also needed. At Bauhaus Earth, for example, we have explored how construction excavation waste, previously a costly disposal problem, can be pressed into load-bearing earth-clay bricks that have an excellent ecological balance without cement additives and are air-dried. This approach immediately proved scalable and is already in high demand.

Currently, the discussion has shifted back to building quickly and simply to address housing shortages in large cities. However, an important step now would be to use the funding from the Infrastructure and Climate Transformation Funds to help regenerative construction methods to a breakthrough – and not artificially keep outdated methods alive. We must take bold action. Now. Because later, it will be much more expensive.

Awareness of the need to tackle climate change is most developed in the old, industrialised countries, which is not surprising. Many poorer countries, for example, in the Sub-Saharan zone, consume much less CO₂ per capita than we do and feel less responsible for fighting the consequences.

We can best change this by conveying the economic benefits that sustainable construction brings. This can be achieved, for example, by using local building materials such as clay, palm leaves, coconut shells or straw, instead of importing expensive reinforced concrete. In other words: we must turn the climate narrative into a development narrative. Time is short since the majority of the expected billion-strong influx into cities will take place in these regions.

Yes, everywhere – from Bhutan to projects in Burkina Faso and Rwanda. Or take Indonesia: in Bali, intensive work is currently underway to use bamboo, which we would usually associate with basic beach bars, for highly complex construction projects. Bamboo is superior to wood in many respects: it grows faster, stores more carbon, and can be processed easily on an industrial scale.

Presuming one understands and uses the material correctly: yes, absolutely. Every material has special qualities, as well as weaknesses. Therefore, there will certainly also be hybrid construction methods involving concrete. And, of course, buildings made of clay or wood will look different and have different forms than those made of concrete; there will be a new aesthetic in architecture.

This page was published in October 2025.