The global center of gravity is increasingly shifting to cities. Urban areas hold just over half of the world’s population,1The World Bank. Urban population (% of total). Retrieved October 12 2018 from: https://data.worldbank.org/indicator/SP.URB.TOTL.IN.ZS. generate roughly 80 percent of global GDP, 2The World Bank. Urban Development Overview. Washington, D.C.: The World Bank. Retrieved October 12 2018 from: http://www.worldbank.org/en/topic/urbandevelopment/overview. and drive 70 percent of global energy-related carbon dioxide emissions.3International Energy Agency (IEA). (2016). Energy Technology Perspectives 2016: Towards Sustainable Urban Energy Systems. Paris, France: IEA. Retrieved from: https://www.iea.org/publications/freepublications/publication/EnergyTechnologyPerspectives2016_ExecutiveSummary_EnglishVersion.pdf. 3.9 billion people currently live in cities, a number expected to climb to 6.4 billion — two-thirds of the world’s population — by 2050.4United Nations (UN). (2014). World Urbanization Prospects. New York, NY: United Nations.
The stakes of cities’ decisions over the following decades are exceptionally high. Many of the Global South cities projected to grow the most have the fewest per capita financial resources.5Bear, V.A., Mahendra, A., & Westphal, M.I. (2016). “Towards a More Equal City: Framing the Challenges and Opportunities.” Working Paper. Washington, DC: World Resources Institute. Retrieved from: http://www.wri.org/sites/default/files/WRR_Framing_Paper_Final_Nov4.pdf. City leaders in these areas often face a difficult balancing act between addressing the urgent and growing need for essential services, and making longer-term decisions and investments that will shape the urban environment — and its residents — for years to come.6Bear, V.A., Mahendra, A., & Westphal, M.I. In more developed cities, officials must grapple with previous land-use and infrastructure decisions that have led to unsustainable levels of resource consumption and set up costly paths for continued development.7Bear, V.A., Mahendra, A., & Westphal, M.I. 8Hower, M. (27 April 2016). The 5 Toughest Challenges Cities Face. GreenBiz. Retrieved from: https://www.greenbiz.com/article/5-toughest-challenges-tomorrows-cities-face.9Ferrão, P., & Fernández, J.E. (2013). Sustainable Urban Metabolism. Cambridge, MA: MIT Press. Around the world, shared challenges such as air pollution and climate change place millions at risk.
Cities also hold unique opportunities to foster equitable and sustainable growth. Denser, more connected, and more coordinated cities could save $17 trillion USD by 2050.10Gouldson, A., et al. (2015). Accelerating Low-Carbon Development in the World’s Cities. Compact urban areas could increase residents’ access to jobs, services and amenities, while reducing infrastructure costs.11The Global Commission on the Economy and Climate (GCEC). (2014). New Climate Economy Technical Note. City policies and practices can help mitigate climate change and build resilience to its impacts.12Newman P. (2006). The environmental impact of cities. Environment and Urbanization, 18(2), 275–295. DOI: 10.1177/0956247806069599. 13The Global Commission on the Economy and Climate (GCEC). (2018). Unlocking the Inclusive Growth Story of the 21st Century: Accelerating Climate Action in Urgent Times. Washington, D.C.: The New Climate Economy.
As cities take on increasing leadership in charting a trajectory that navigates these challenges, the goals of fostering inclusive, equitable development and successful environmental management are deeply intertwined. Environmental burdens and risks — such as air pollution, heat waves, extreme weather events, and the risk of floods and droughts — can sharpen inequality,14Samuel, K. (5 October 2018). What Happens When Climate Adaptation Meets Social Isolation? Medium. Retrieved from: https://medium.com/@kimsamuelcanada/what-happens-when-climate-adaptation-meets-social-isolation-e31d586a9c6515The Global Commission on the Economy and Climate (GCEC). (2018). Unlocking the Inclusive Growth Story of the 21st Century: Accelerating Climate Action in Urgent Times. Washington, D.C.: The New Climate Economy. 16Revi, A., Satterthwaite, D.E., Aragón-Durand, F., Corfee-Morlot, J., Kiunsi, R.B.R., Pelling, M, Roberts, D.C., & Solecki, W. (2014). Chapter 8: Urban areas. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, pp 535-612. while access to environmental benefits, such as green space and public transit, can help mitigate it. Building public transit to connect underserved communities to the city center helped Medellin, Colombia transform from the world’s murder capital to into a safer and more inclusive city.17Bear, V.A., Mahendra, A., & Westphal, M.I. (2016). “Towards a More Equal City: Framing the Challenges and Opportunities.” Working Paper. Washington, DC: World Resources Institute. Retrieved from: http://www.wri.org/sites/default/files/WRR_Framing_Paper_Final_Nov4.pdf.18Madrid, J. (13 March 2012). Medellin’s Amazing Metro System: Colombia Uses Public Transport To Drive Societal Change. ThinkProgress. Retrieved from: https://thinkprogress.org/medellins-amazing-metro-system-colombia-uses-public-transport-to-drive-societal-change-1a4186f6c3c6/. Programs fostering social cohesion can lessen the impacts of urban heat waves and build resilience to extreme weather events and natural disasters. 19Samuel, K. (5 October 2018). What Happens When Climate Adaptation Meets Social Isolation? Medium. Retrieved from: https://medium.com/@kimsamuelcanada/what-happens-when-climate-adaptation-meets-social-isolation-e31d586a9c65. 20Townshend, I., Awosoga, O., Kulig, J., & Fan, H. (2015). Social cohesion and resilience across communities that have experienced a disaster. Natural Hazards, 76(2), 913-938.21Aldrich, D. P., & Meyer, M. A. (2015). Social capital and community resilience. American Behavioral Scientist, 59(2), 254-269.
Data will be imperative to enabling cities to address these integrated challenges. At the moment, frameworks that compare cities’ progress and challenges — and assess how this performance varies across different neighborhoods — remain scarce. The UESI provides a resource that tracks neighborhood-level access to environmental goods and exposure to environmental harms to help city managers and urban residents understand how the environmental quality of life varies across different locations and socioeconomic demographics. This report also provides a starting point and proof of concept for understanding how the application of large-scale and unconventional datasets — from satellite data to OpenStreetMap — can create a comprehensive, detailed, and timely dataset of urban performance. Over time, the UESI aims to provide a flexible and adaptable framework and data source that new cities can adapt for their own analysis and management purposes.
We find overall that cities are not meeting the charge of sustainable and inclusive environmental policies. Although there are some cities that perform well on the UESI’s environmental indicators, nearly all are burdening poorer populations with the consequences of uneven air pollution distribution, access to tree cover, public transit, and exposure to urban heat. We see that income still plays a strong role in determining environmental performance in many cities, with cities tending to cluster on the UESI results with other cities of a similar economic development status. Higher levels of income, however, do not determine equitable outcomes, as the UESI results show wealthy and poor cities alike are placing the greatest environmental inequalities on poorer populations. For instance, urban heat island intensity places a greater burden on poorer populations in Atlanta, Los Angeles, and Mexico City. Johannesburg‘s high levels of income inequality are compounded by inequitable distributions of urban heat island, urban tree cover, and distance to public transit, which disproportionately burden lower income earners.
Data gaps still remain: vital socioeconomic data proved especially difficult to collect and standardize across different urban contexts, while tools like OpenStreetMap are prone to gaps in volunteers’ data collection. Data alone, however, is not a panacea — cities’ ability to investigate and respond to data signals depends on technical knowledge, financial resources, and political will. The continued growth of mobile phones and information communication technology and the innovation in new modes of data collection have the potential to help ground and inform cities’ growing role in fostering sustainable development. We hope this tool provides a starting point and sparks a discussion about how role of data in support urban sustainability to create a more robust dataset of urban triumphs and challenges, and to mobilize support for efforts to chart safe, inclusive future.