Empowering cities globally: Four levers for transformative urban adaptation with nature-based solutions.

The latest report of the Intergovernmental Panel on Climate Change showed that upcoming decades are likely to be accompanied with an increase in climate impacts in urban areas, thereby stressing the need for empowering cities to help them address the challenges ahead by closing the urban adaptation gap. The lock-in systems in which cities are often trapped create resistance to change and leads to missed opportunities to cocreate better futures. Putting nature at the center of urban adaptation agenda is a promising vision that nature-based solutions can help realize if city leaders are adequately supported in accessing the knowledge and resources they need to take action. Despite their proven potential, important barriers to the planning, implementation, and management of nature-based solutions (NbS) for urban climate adaptation persist and need to be urgently addressed. We highlight key barriers related to knowledge gaps and dissemination, policy incentives, and financial autonomy faced by city leaders trying to integrate NbS into policy and planning. In this perspective, we propose four levers of transformative adaptation which build on examples from Europe, the United States, Africa, and Latin America and which have proven successful in supporting cities adopting nature-based adaptation actions, including to 1) produce, assess and share knowledge; 2) adopt incentive-based policies and regulations; 3) facilitate access to multiple sources of funding; and 4) create reflexive monitoring mechanisms. If these steps are taken with the goal of addressing vulnerabilities on the ground, they can unleash the potential of NbS to engage on a path of transformative adaptation.