This includes extreme weather events, financial crises, for example in Malmö (Anderson, 2014; Isaksson and Heikkinen, 2018), and the COVID-19 pandemic (e.g., Milan), all of which have disrupted the status quo and accelerated innovation and implementation (e.g., Milan; see Box 13.3; Cross-Chapter Box COVID in Chapter 7).Considerable barriers exist that prevent system transitions from taking place in Europe, including institutional and behavioural lock-ins such as administrative routines, certain types of legislation and dominant paradigms of problem solving