Understanding cities comprehensively as systems is a costly challenge and is typically not feasible for policy makers. Nevertheless, focusing on some key systemic characteristics of cities can give useful insights for policy to advance health and well-being outcomes. Moreover, if we take a coevolutionary systems view of cities, some conventional assumptions about the nature of urban development (e.g. the growth in private vehicle use with income) may not stand up. We illustrate this by examining the coevolution of urban transport and land use systems, and institutional change, giving examples of policy implications. At a high level, our concern derives from the need to better understand the dynamics of urban change, and its implications for health and well-being. At a practical level, we see opportunities to use stylised findings about urban systems to underpin policy experiments. While it is now not uncommon to view cities as systems, policy makers appear to have made little use so far of a systems approach to inform choice of policies with consequences for health and well-being. System insights can be applied to intelligently anticipate change - for example, as cities are subjected to increasing natural system reactions to climate change, they must find ways to mitigate and adapt to it. Secondly, systems insights around policy cobenefits are vital for better informing horizontal policy integration. Lastly, an implication of system complexity is that rather than seeking detailed, 'full' knowledge about urban issues and policies, cities would be well advised to engage in policy experimentation to address increasingly urgent health and climate change issues.
Extreme events, both natural and anthropogenic, increasingly affect cities in terms of economic losses and impacts on health and well-being. Most people now live in cities, and Asian cities, in particular, are experiencing growth on unprecedented scales. Meanwhile, the economic and health consequences of climate-related events are worsening, a trend projected to continue. Urbanization, climate change and other geophysical and social forces interact with urban systems in ways that give rise to complex and in many cases synergistic relationships. Such effects may be mediated by location, scale, density, or connectivity, and also involve feedbacks and cascading outcomes. In this context, traditional, siloed, reductionist approaches to understanding and dealing with extreme events are unlikely to be adequate. Systems approaches to mitigation, management and response for extreme events offer a more effective way forward. Well-managed urban systems can decrease risk and increase resilience in the face of such events.
The term "co-benefits" refers to positive outcomes accruing from a policy beyond the intended outcome, often or usually in other sectors. In the urban context, policies implemented in particular sectors (such as transport, energy or waste) often generate multiple co-benefits in other areas. Such benefits may be related to the reduction of local or global environmental impacts and also extend into the area of public health. A key to identifying and realising co-benefits is the adoption of systems approaches to understand inter-sectoral linkages and, in particular, the translation of this understanding to improved sector-specific and city governance. This paper reviews a range of policies which can yield health and climate co-benefits across different urban sectors and illustrates, through a series of cases, how taking a systems approach can lead to innovations in urban governance which aid the development of healthy and sustainable cities.
In the first paper in this Series we assessed theoretical and empirical evidence and concluded that the health of people living in slums is a function not only of poverty but of intimately shared physical and social environments. In this paper we extend the theory of so-called neighbourhood effects. Slums offer high returns on investment because beneficial effects are shared across many people in densely populated neighbourhoods. Neighbourhood effects also help explain how and why the benefits of interventions vary between slum and non-slum spaces and between slums. We build on this spatial concept of slums to argue that, in all low-income and-middle-income countries, census tracts should henceforth be designated slum or non-slum both to inform local policy and as the basis for research surveys that build on censuses. We argue that slum health should be promoted as a topic of enquiry alongside poverty and health.
Massive slums have become major features of cities in many low-income and middle-income countries. Here, in the first in a Series of two papers, we discuss why slums are unhealthy places with especially high risks of infection and injury. We show that children are especially vulnerable, and that the combination of malnutrition and recurrent diarrhoea leads to stunted growth and longer-term effects on cognitive development. We find that the scientific literature on slum health is underdeveloped in comparison to urban health, and poverty and health. This shortcoming is important because health is affected by factors arising from the shared physical and social environment, which have effects beyond those of poverty alone. In the second paper we will consider what can be done to improve health and make recommendations for the development of slum health as a field of study.