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A planetary outlook for urban health

As cities turn into urban systems, urban health risks become planetary.

To date, more than 900 people in China have died from the novel coronavirus (2019-nCoV).  This virus originated in Wuhan, Central China, spread to other parts of China, and several other countries.  The number of people infected worldwide has passed 30,000 – with the majority of cases and deaths occurring in China (Nature Briefing, February 10, 2020). This recent outbreak is a serious warning that with cities turning into urban systems the threat of urban health risks are becoming planetary.  Apart from the spread of diseases, also the environmental impacts of urbanisation, in particular pollution,  pose a growing threat to the health of people and the planet. Urban health risks are becoming planetary. Apart from the spread of diseases, also the environmental impacts of urbanization, in particular pollution, pose a threat to the health of people and the planet. Peter Daszak, the president of EcoHealth Alliance, a private research organization based in New York, explains that we made the virus by disrupting natural environments ecosystems:

Thereby “we shake viruses loose from their natural hosts. When that happens, they need a new host. Often, we are it.”

Urban health risks are becoming planetary.

In 2005, Galea and Vlahov (2005) reflected on the evidence, challenges and directions of urban health and pointed out that the advantage of living in cities can and for many is, turning into a penalty. Urban health is understood as the overall (mental, social, physical) health of people living in urban environments. The fact that despite increasing life expectancies the number of people living in urban slums and informal settlements is increasing, is only one indication of the urban health penalty Galea and Vlahov referred to.

In 2014, Cities Alliance (2014) called our attention to the shifting economic geography of cities and the disparities across many parts of the national and international systems of cities. Of particular interest and concern are cities with less than a million people in Africa and Latin America, for example. These “secondary cities” (Rondinelli, et al. 1983) are largely urban and, according to UN-Habitat, generally comprise of a population of between 100,000 and 500,000. As urban growth centers, they contribute significantly to the disparate health status of urban populations. Rapid urbanization without planning and organization, contribute to considerable environmental, social, health costs globally.

In 2016, the WHO and UN-Habitat published a global report on urban health which aimed at assessing the health conditions of cities. The results were varied and are not easily comparable. However, WHO’s (2014) Urban Health Index (UHI) provides some key findings:

  • Country-level wealth is not always a good predictor of urban health. Some upper-middle income countries had very low UHI values for their cities;
  • Megacities in low- and middle-income countries have worse conditions for health than smaller cities;
  • Conditions for health vary widely within the same geographic region and within cities;
  • Those cities in Africa which where effected by the 2014-2015 Ebola outbreak were among the cities with the lower UHI.

Limited progress has been made to address these concerns. Some of the most worrying trends in urban health include:

  • Increasing urban population numbers and increasing numbers of people living in slums. The World Cities Report (2016) finds that around a quarter of the world’s urban population lives in slums;
  • Increasing inequality; the bigger the city the larger its income inequality tends to be;
  • Increasing prevalence of non-communicable diseases; the urban environment is now one of the first causes of disease, injury and death (Sarkar and Webster 2017);
  • Ageing cities; the older population grows faster in cities than the overall population and faster than in rural areas (OECD 2019);
  • Climate change in cities; health of people in cities will be affected by rising sea levels, increasing precipitation, floods, more frequent and stronger storms and extreme heat and cold (UN Habitat 2019);
  • Growing demand (and scarcity) of water, food and energy for cities. Two-thirds of the global population (4.0 billion people) live under conditions of severe water scarcity at least 1 month of the year; 14 of the world’s 20 megacities are experiencing water scarcity or drought (Mekonnen and Hoekstra 2016).

Urban health problems are complex and interconnected. They are evidence of health being an emergent property of multiple interconnected social, technological and ecological systems of which cities comprise, and which people are part of. Most of those health challenges cannot be regarded as an illness which requires a treatment in isolation from other symptoms. The dilemma of the urban advantage is that the same improved conditions of connectivity and mobility, which foster growth and efficiency, also contribute to the urban health penalty. “Faster, closer, better” also means more light, noise, air pollution and it stresses people in their quest to find the best opportunities and make the most use of their urban advantage.

Although, the systems view of cities has largely been accepted in the health and urban sciences, urban health is still largely seen from an anthropocentric instead of an eco-centric perspective. Therefore, apart from finding scientific evidence which could help improve urban health, changing the dominant scientific outlook on urban health would make a big difference. The urban health problems we are facing today, are systemic and therefore require us to ask different kinds of questions. Today most urban health experts are still asking, “In which health conditions are people in changing urban environments?” and “How do urban environments impact human health?”, while we need to ask: “In which health condition are urban systems?”, “How do healthy urban systems function”, and “How do human and urban environmental health co-evolve?”.

Cities of the future are not just potential breeding grounds of infectious diseases, but rather they are the places where diseases can be detected, treated and stopped from spreading. Also when it comes to environmental impacts, cities are not just places of consumption and pollution but hubs from which creative and innovative solutions for transport, energy, education, the economy, housing or food systems origin. Such a shift from health in urban environments to healthy urban systems could change science and policy agendas, create co-benefits in connecting urban and planetary health and make an important impact not just for avoiding pandemics but also for achieving sustainable development on an urban planet.


Franz W. Gatzweiler is Executive Director of the Urban Health and Wellbeing programme. The Urban Health & Wellbeing programme proposes a new conceptual framework for considering the multi-factorial nature of both the determinants and the manifestations of health and wellbeing in urban populations.

Yonette F. Thomas is a globally acknowledged thought leader, urban health champion, and an advocate for valuing the health of women and girls as an economic imperative.  She is currently the Global Advisor for the Centre for Urban Health and Development within the Asian Institute of Poverty Alleviation (CUHD-AIPA).  She served as the inaugural Executive Director of the International Society for Urban Health (ISUH) for the past two and a half years.She is a founding board member of the ISUH and has served as a science advisor for urban health to the New York Academy of Medicine. She is a founding board member and former vice president of the Interdisciplinary Association for Population Health Science (IAPHS) and served on the Steering Committee of the National Hispanic Science Network on Drug Abuse for more than a decade. She formerly served as the Associate Vice President for Research Compliance at Howard University in Washington, DC.

This piece was first published on the Urban Health and Wellbeing programme website, and was updated on 10 February 2020 to include the latest data on novel coronavirus (2019-nCoV) mortality.

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