To live up to its climate change pledge under the Paris Agreement, the European Union must ensure that all 250 million existing buildings, as well as all new buildings in the EU, produce near-zero greenhouse gas emissions. In a new report, European national academies of science, through their association EASAC, call for far-reaching policy action. "Policies have long focused on creating energy-efficient buildings that require less heating and air conditioning or generate renewable energy on site. However, the energy used to operate buildings is only part of the story. We need to broaden the scope and look at emissions from building materials and methods - both for new buildings and for building refurbishment," says William Gillett, Director of EASAC's Energy Programme.