Seite - 412 - in Biodiversity and Health in the Face of Climate Change

412 Highlights • Cities are experiencing multiple impacts from global environmental change. • A systems perspective can lead to innovative designs of new urban infrastructure and the redesign of existing structures to address complex urban health challenges. • The integration of grey, green and blue infrastructure in urban planning through institutional innovation and structural reorganization of knowledge-action sys- tems may result in large health improvements and increase urban resilience. 18.1 Introduction Urban health and well-being is an outcome of urban complexity. In this chapter we argue that cities are complex adaptive social-ecological-technological systems, a perspective needed in order to untangle this complexity and define the types of problems we are confronted with (Alberti et  al. 2018). By framing complexity con- ceptually we suggest pathways for urban governance for urban health and well- being, pathways that address problems of great scientific and economic complexity and radical uncertainty, of which climate change is a prime example. One example of such a pathway is using multiple ecosystem services as a means to create resil- ience to climate change in cities and thus reduce negative impacts on  health and well-being, or so-called ‘nature-based solutions’ (NBSs) (Secretariat of the Convention on Biological Diversity 2009), such as the ‘Sponge City’ initiative for flood water treatment currently taking place in China and the green roof design thriving across many European cities. Whereas technology can be helpful for solv- ing complicated engineering problems by seeking solutions for optima and equilib- ria, complex or inexact problems require the recognition of deep uncertainty and non-linearity. 18.1.1 Urban Systems as  Complex Adaptive Systems A social-technological approach has, up until now, been the traditional way of ana- lyzing urban complexity (e.g. Geels 2011; Hodson and Marvin 2010), and in this context, many have struggled to define exactly what is meant by a city. Here we expand on an emerging framework of cities as complex social-ecological- technological systems, as cities include much more than a particular density of peo- ple or area covered by human-made structures (Bai et  al. 2016; Alberti et  al. 2018). Cities are places where social, ecological and technological systems connect and integrate; where various types of capital and infrastructures intersect in multi- dimensional spaces; and where connectivity, interaction, exchange and com- munication accelerate in time. Urban socio-ecological-technological systems are T. Elmqvist et al.