The building sector is one of the biggest levers in the fight against the climate crisis. At the same time, it is under increasing pressure to transform: decarbonisation, the circular economy, ESG reporting and the EU taxonomy are fundamentally changing the requirements. The IBA Forum editorial team spoke to Michael Wiebelt, M.O.O.CON, about why existing buildings play a key role—and how companies who take a stance can reduce not only emissions but also costs and risks.