Faced with advanced climate change, a consistent environmental ethic requires a radical change in housing supply – more radical than what seems politically feasible. In FiFo Discussion Paper 23-1, Andreas Becker, Head of the Climate Monitoring Department at the German Weather Service, and Klaus Mackscheidt explore the need for adaptation, the options for flexible housing and for new construction only in the case of immigration. In their essay, they argue in favour of an ambitious policy of many small steps – knowing that the “big leaps” too often fail and result in (temporary) paralysis.