Earth’s Future COMMENTARY 10.1002/2014EF000258 Special Section: Urbanization, carbon cycle, and climate change Key Points: • We need integrated, coproduced approaches to urbanization, urban areas, and carbon • Urbanization uncertainties are of similar magnitude to carbon uncertainties • Lock-ins in urbanization, cities, and carbon constrain low-carbon transitions
Corresponding author: P. Romero-Lankao,
[email protected]
Citation: Romero-Lankao, P. et al. (2014), A critical knowledge pathway to low-carbon, sustainable futures: Integrated understanding of urbanization, urban areas, and carbon, Earth’s Future, 2, doi:10.1002/2014EF000258.
Received 22 MAY 2014 Accepted 19 AUG 2014 Accepted article online 29 AUG 2014
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ROMERO-LANKAO ET AL.
A critical knowledge pathway to low-carbon, sustainable futures: Integrated understanding of urbanization, urban areas, and carbon Patricia Romero-Lankao1, Kevin R. Gurney2, Karen C. Seto3, Mikhail Chester4, Riley M. Duren5, Sara Hughes6, Lucy R. Hutyra7, Peter Marcotullio8, Lawrence Baker9, Nancy B. Grimm2, Christopher Kennedy10, Elisabeth Larson11, Stephanie Pincetl12, Dan Runfola13, Landy Sanchez14, Gyami Shrestha15, Johannes Feddema16, Andrea Sarzynski17, Joshua Sperling1, and Eleanor Stokes3 1 Urban
Futures, National Center for Atmospheric Research, Boulder, Colorado, USA , 2 School of Life Sciences/Global Institute of Sustainability, Arizona State University, Tempe, Arizona, USA , 3 Yale School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, USA , 4 School of Civil, Environmental, and Sustainable Engineering, Arizona State University, Phoenix, Arizona, USA, 5 Jet Propulsion Laboratory, NASA, Pasadena, California, USA, 6 Department of Political Science, University of Toronto Mississauga, Toronto, Canada, 7 Department of Earth and Environment, Boston University, Boston, Massachusetts, USA, 8 Department of Geography, Hunter College, City University of New York, New York, New York, USA, 9 Department of Bioproducts and Biosystems Engineering, University of Minnesota, St. Paul, Minnesota, USA, 10 Department of Civil Engineering, University of Toronto, Toronto, Ontario, Canada, 11 AAAS, Science Policy Fellow, Terrestrial Ecology Program, Earth Sciences Division, NASA, Washington, District of Columbia, USA, 12 Institute of the Environment and Sustainability, University of California, Los Angeles, California, USA, 13 AidData, Institute for the Theory and Practice of International Relations, The College of William and Mary, Williamsburg, Virginia, USA, 14 Centro de Estudios Demográficos, Urbanos y Ambientales, El Colegio de Mexico, Mexico City, Mexico, 15 U.S. Carbon Cycle Science Program, U.S. Global Change Research Program, UCAR, Washington, District of Columbia, USA, 16 Department of Geography, University of Kansas, Lawrence, Kansas, USA, 17 George School of Public Policy and Administration, University of Delaware, Newark, Delaware, USA
Abstract Independent lines of research on urbanization, urban areas, and carbon have advanced our understanding of some of the processes through which energy and land uses affect carbon. This synthesis integrates some of these diverse viewpoints as a first step toward a coproduced, integrated framework for understanding urbanization, urban areas, and their relationships to carbon. It suggests the need for approaches that complement and combine the plethora of existing insights into interdisciplinary explorations of how different urbanization processes, and socio-ecological and technological components of urban areas, affect the spatial and temporal patterns of carbon emissions, differentially over time and within and across cities. It also calls for a more holistic approach to examining the carbon implications of urbanization and urban areas, based not only on demographics or income but also on other interconnected features of urban development pathways such as urban form, economic function, economic-growth policies, and other governance arrangements. It points to a wide array of uncertainties around the urbanization processes, their interactions with urban socio-institutional and built environment systems, and how these impact the exchange of carbon flows within and outside urban areas. We must also understand in turn how carbon feedbacks, including carbon impacts and potential impacts of climate change, can affect urbanization processes. Finally, the paper explores options, barriers, and limits to transitioning cities to low-carbon trajectories, and suggests the development of an end-to-end, coproduced and integrated scientific understanding that can more effectively inform the navigation of transitional journeys and the avoidance of obstacles along the way. 1. Why Urbanization, Urban Areas, and Carbon? In recent years, the relationships between urbanization, urban areas, and the carbon cycle have generated increased interest in research and policy circles for a variety of reasons. We have urbanized our planet to an unprecedented level. The concentrations of infrastructure, economic and social activities, and populations in cities create growing demands for fossil fuels and carbon-intensive materials to build and power domestic services, commercial buildings, industrial processes, telecommunications systems, water © 2014 The Authors.
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provision, waste production, travel, and a seemingly endless array of other uses. By 2050, the global urban population is expected to increase from 3.6 billion to over 6 billion, mainly in low- and middle-income countries [United Nations Department of Economic and Social Affairs, 2010]. With urban extent forecast to triple between 2000 and 2030, more urban land expansion will occur during the first three decades of the 21st century than in all of human history [Seto et al., 2012a]. This projected growth in urban land use creates an increased urgency to develop an integrated understanding of urbanization and urban areas in the global carbon cycle. This urgency is highlighted by the fact that even though urban areas occupy
