The committee has developed the following set of findings and recommendations based on its review and synthesis of the information gathered during the course of this study. This set of findings and recommendations has been drawn from specific city profiles, which can be found in Chapter 4, and is meant to encompass the nature of both the urban sustainability principles and the committee’s urban sustainability roadmap. These findings and recommendations can guide academics, practitioners, policy makers, civil society, corporate leaders, and other stakeholders engaged in metropolitan regions to achieve greater sustainability and, by extension, greater global sustainability. The committee recognizes that local governments vary in their configurations, leadership structures, and offices; thus, for the purposes of this report, the following text addresses cities generally and sustainability coordinators in particular as the actors for these recommendations.
Global Constraints and Co-dependencies
Finding 1: The sustainable city exists within the larger contexts of the planet’s finite resources and the city’s linkages with other cities and regions, in addition to the region within which it exists.
Achieving urban sustainability requires recognizing interconnections among places and the associated impacts of actions. Each of the cities investigated for this report is located within or adjacent to regions upon which they depend for resources and, in turn, provide resources. Los Angeles obtains water several hundred miles away with almost two-thirds of its supply originating from outside of its region. Similarly, air pollutants originating in the City of Los Angeles impact cities and counties downwind such as Riverside and San Bernardino; thus, air quality issues in Los Angeles are best considered at the basin scale rather than only the city or county. Alternatively, other cities such as Cedar Rapids, located in landscapes rich in water and other resources, supply food staples to other regions and communities. In Vancouver, Canada, residents’ recognition of the value of Vancouver’s natural surroundings prompted actions by the city to protect these valuable assets, such as designating local wild spaces as parks and encouraging extractive industries to move elsewhere.
In order to put local sustainability plans into a global context, understanding must be developed about the extent to which local sustainability programs can contribute to—or might in fact impede—global solutions (see Day et al., 2014; Liu et al., 2015; UNEP, 2012). This will require deeper comprehension of the nature and functioning of linkages among cities and of the positive and negative impacts of interplace interactions on the places of origin and destination for the flows of goods, services, and information. Also required is a complete and honest accounting of the urban metabolism—stocks and flows of materials, energy, and information—of cities. Cities such as Los Angeles, where sustainability policy making has a local to national orientation; Cedar Rapids, where policies are oriented toward supporting sustainability beyond its environs; and Vancouver, where municipal planning has made the city a model for the practice in other metropolitan areas globally provide valuable examples of linking urban footprints beyond the confines of administrative or municipal boundaries.
Recommendation 1: Actions in support of sustainability in one geographic area should not be taken at the expense of the sustainability of another. Cities should implement local sustainability plans and decision making that have a larger scope than the confines of the city or region.
Importance of Incorporating Cross-scale Processes
Finding 2: Strategies implemented at a single scale or sector are often ineffective because they are not coupled to other relevant scales and sectors.
The biophysical, economic, and social processes that define urban sustainability take place at multiple geographic scales ranging from the housing unit to the globe. Sustainability planning actions targeted at one spatial scale are likely to have impacts at other scales; urban planners and policy makers need to identify the linkages among the different spatial scales relevant to particular sustainability processes and integrate planning and strategies across scales to ensure policy effectiveness.
Linkages among the worldwide network of cities, as well as linkages through the vertical cooperation among partners in specific places, are salient. These linkages can provide needed connections to translate local engagement into state or national actions. Sustainability actions are likely to be most effective when they integrate across different geographical and governance scales and across the social, environmental, and economic dimensions of sustainability. In Chattanooga, the genesis of sustainability planning came from “[inviting] the whole community to bring their ideas to the discussion about the future of [the city],” resulting in increased recognition of these important cross-scale processes (Lerner, 1998). For example, the climate action strategies aimed at greenhouse gas (GHG) emissions reduction included coal-to-gas conversion through partnerships at the regional level between the municipal power utility and the regional power utility, and at the local level, incentivized residents to invest in green electric power, achieving economic, environmental, and social benefits across all scales. In addition, municipal sustainability planners and urban leaders in Vancouver have been recognized for successfully integrating their activities across geographic scales (EIU, 2011). A number of initiatives under the city’s Greenest City Action Plan span spatial and administrative scales, from the block and community levels to district and regional levels.
Recommendation 2: Urban leaders and planners should integrate sustainability policies and strategies across spatial and administrative scales, from block and neighborhood to city, region, state, and nation, to ensure the effectiveness of urban sustainability actions.
Cross-cutting Challenges, Solutions, and Co-benefits
Finding 3: Many urban sustainability challenges cut across more than one dimension of sustainability. Sustainability policies, designed to simultaneously address problems along different dimensions, can yield co-benefits for two or all three sustainability dimensions while considering tradeoffs.
As illustrated in the Chattanooga example of GHG emissions reduction strategies, policies and actions that support one dimension of sustainability can also enhance other dimensions. For example, increased safety in a neighborhood typically leads to increased commerce. These types of co-benefits can justify expenditures in one area because of the value or return on investment across multiple dimensions. However, if improvements are repeatedly confined to the same two dimensions, they may not have the longer-term durability needed. Environmental and economic performance can improve in spite of lingering social inequities, but ultimately those inequities need to be diminished to ensure long-term sustainability. Chattanooga’s air pollution reduction policies and innovative “gigabit city” concept promote sustainability across multiple dimensions and have led to substantive quality-of-life improvements and the attraction of young entrepreneurs from across the globe, yet serious social inequities remain (Hundt et al., 2009). In Philadelphia, the city’s water department has become a nationally recognized innovator in stormwater management through the use of Green Stormwater Infrastructure installations throughout the city, resulting in more green spaces and tree canopy cover and associated social benefits of recreation spaces (Kondo et al., 2015). The city has also, through a public-private partnership, acquired and greened around 5,000 vacant lots, the equivalent of over 200 acres of land, resulting in largely beneficial impacts across sustainability dimensions in entire neighborhoods.
Recommendation 3: Urban leaders and planners should implement sustainability policies and programs that identify and establish processes for promoting synergies among environmental, economic, and social policies that produce co-benefits across more than one dimension of sustainability.
Shared versus Unique Challenges
Finding 4: All cities share certain sustainability challenges though the severity of these shared challenges varies from place to place. Each city’s pathway to sustainability will likely include components common to other urban areas, components that are shared, and components unique to that city.
Commonalities and uniqueness are reflected in the cities covered in this report. For example, severe water challenges exist in many different forms; shortages and droughts have been keenly felt and partially addressed by Los Angeles, prompting water usage reductions, while Flint has experienced severe drinking water quality problems, when disconnection from a municipal water source and shift to a river source yielded corrosive water. In contrast, New York City generally has an abundant high-quality water supply, though short-duration droughts occur periodically. An excess of water during storm-related flooding and flash flooding has been experienced by many cities and is expected to continue in the face of anticipated extreme weather events and climate change. Additionally, practically all of the cities share vulnerabilities to climate change, but the degree and type of vulnerability varies greatly (e.g., drought for Los Angeles and sea-level rise for New York City).
Housing costs also highlight variability across cities. Insufficient affordable housing, a growing population, and high poverty rates contribute to the housing dilemma and homelessness crisis in Los Angeles. Vancouver, a city with a comparatively high median household income, has also faced issues of housing cost, as land and housing scarcity have driven up housing prices, making the city unaffordable for young families. The high cost of housing is less prominent in Pittsburgh and Grand Rapids.
Beyond these examples, such challenges and variations are shared across cities globally. Solutions and best practices in all three dimensions of sustainability can flow to U.S. cities from other examples nationally, as well as internationally—from other parts of the Global South and Global North beyond the United States, despite local variations on shared issues. In Los Angeles, New York City, and Vancouver, sustainability managers and planners in each city actively participate in regional to global networks of similarly minded planners, in order to draw upon relevant experiences and lessons (successful and otherwise). All three cities participate in C40, an elite international group of the most environmentally progressive cities. Vancouver is also a member of the Carbon Neutral Cities Alliance, a cohort of 17 international cities with the most aggressive environmental goals.
Recommendation 4: Urban leaders and planners should look to cities with similar economic, environmental, social, and political contexts to understand and adapt sustainability strategies that have proven to provide measurable impact.
The Key Role of Science
Finding 5: Science-based solutions that are successful locally can provide useful information to other urban areas around the world.
Sharing among cities requires evidence, and science can aid in the sharing process through establishment of scientific generalizability. Consistent and objective science input is needed to distinguish programs with merely anecdotal credibility from those that have demonstrated impact and results.
Urban sustainability practitioners take two kinds of actions: those that are driven by science and make measurable progress toward sustainability goals, and those that are visible and intended to motivate the community. For example, urban farming has anecdotal credibility, but little solid evidence that it creates benefits; in fact, it may even have negative components, i.e., risks related to irrigation of food crops with urban wastewater and the use of fertilizers and pesticides (Stewart et al., 2013; van Veenhuizen, 2006). It does, however, have community development co-benefits (see Recommendation 3) that may justify urban farming programs.
Alternatively, the case of Grand Rapids demonstrates how actions driven by science can make concrete contributions to urban sustainability goals. The city’s first sustainability plan was developed using indicators and specific targets guided by research and data, and further expanded upon in the establishment of baselines for future outcomes assessment through data collection on sustainability measures (Liobimtseva, 2013; Western Michigan Environmental Action Council, 2013).
Recommendation 5: Urban leaders and planners should gather scientific input to the maximum extent available in the form of metrics on social, health, environmental, and economic dimensions of sustainability; data related to policies, programs, and implementation processes; and measures of community involvement.
Partnerships for Sustainability
Finding 6: Key pathways to urban sustainability include institutional and sectoral collaborations across stakeholder groups, sustained citizen engagement, effective leadership, and long-term commitment to the issue.
Public-private partnerships have been shown to be effective in generating and implementing changes that improve environmental, economic, and overall quality-of-life indicators. Of the cities investigated for this report, no durable sustainability initiatives were observed that did not include some form of partnering. The Long Beach Aquarium has an extensive list of local, state, and national partners on a variety of projects and endeavors, while Grand Rapids and Chattanooga receive broad-based community support, in both cases through the partnership of business leadership with local government and citizen engagement to facilitate comprehensive sustainability approaches, e.g., the Grand Rapids Area Community Sustainability Partnership and Chattanooga’s Vision 2000 (Hundt et al., 2009; Price, 2011). Universities, national laboratories, foundations, and other independent third-party institutions can act as conveners and mediators to move communities toward sustainability. In addition, successful cities have formed an inner-city sustainability council with representation of key city stakeholders, in addition to engaging with external stakeholders.
Recommendation 6: Cities should ensure broad stakeholder engagement in developing and implementing sustainability actions with all relevant constituencies, including nontraditional partners.
Durable and Dynamic Sustainability Planning
Finding 7: Cities that have developed a cohesive sustainability plan with dedicated funding and measurable objectives improve their chance of making substantial progress toward sustainability.
One of the initial mechanisms for sustainability is the production of a citywide sustainability plan used to coordinate interdepartmental actions (see Box 5-1). All nine of the cities included in this report have sustainability plans backed by some kind of funding mechanism and a process for revision and updating. However, the vast majority of urban areas do not have sustainability officers, written sustainability plans, or the dedicated funding and capacity to revise and update those plans periodically in light of changing environmental, social, and economic conditions. For instance, the Urban Sustainability Directors Network, a peer-to-peer network of local government professionals from cities across the United States and Canada, has over 135 members representing cities and counties. Other notable networks include the Mayors National Climate Action Agenda, a nationwide coalition of mayors of 28 cities on climate change, and C40, an elite international group of the most environmentally progressive cities. However, according to the U.S. Census Bureau, the United States has over 19,354 “incorporated places” (U.S. Census Bureau, 2012). Many sustainability elements, however, are contained within comprehensive, sector-specific, or subarea plans, such as those devoted to energy, climate, and transportation. Though they lack the breadth of sustainability plans, they contain and contribute important elements for sustainability planning.
To be successful, cities will need durable, long-standing sustainability leadership structures written prominently into their operating budgets and plans and, where possible, voted into perpetuity by their citizens.
It is important to note that the mere presence of a sustainability plan does not equate to sustainability, nor does it necessarily signify the successful transition of a city to a sustainability agenda. Also, the presence of a plan assumes the capacity for implementation, which is not the case in all urban areas. A sustainability plan should rather be viewed as a set of intentional actions selected by a city and a community, and as an essential first step in the process.
Recommendation 7: Every city should develop a cohesive sustainability plan that acknowledges the unique characteristics of the city and its connections to global processes while supporting mechanisms for periodic updates to take account of significant changes in prevailing environmental, social, and economic conditions. Sustainability plans should strive to have measureable characteristics that enable tracking and assessment of progress, minimally along environmental, social, and economic lines.
Improving Opportunities, Outcomes, and Quality of Life for All
Finding 8: Reducing inequalities promotes well-being along economic and environmental dimensions, as well as the social dimension of sustainability.
Vulnerable populations are disproportionately affected by extreme weather events and by human-made challenges such as historic and contemporary discrimination, and lack of access to jobs, housing, public goods, and services. Addressing these issues results in improved quality of life for all. The opportunity to improve quality of life broadly throughout a city by reducing inequality is a fundamental, but often overlooked, aspect of sustainability planning. Addressing these issues reinforces the linkages across sustainability dimensions and the co-benefits associated with a triple-bottom-line approach.
Much of the impact of inequality falls on the elderly and children. Underprivileged populations are often more vulnerable than others to natural and human-made disasters. As a result, reducing inequality can improve the resilience of communities to both natural and economic disasters. The committee recognizes that inequality will not be completely eliminated; nevertheless, a focus on reducing inequality is a worthy goal and can produce useful co-benefits.
As noted in Recommendation 3, social inequities are often exacerbated by changing environmental and economic conditions. In recognition of this, New York City’s plan, One New York, has combined equity with environment and resilience. This provides a broader definition of inequity, suggesting new ways for defining poverty and adding new meaning and purpose to services provided to low-income people, such as New York City’s affordable housing program. More broadly, Philadelphia, Los Angeles, and New York City all provide examples wherein sustainability planning combines equity, environmental, and resilience policies (City of Los Angeles, 2007; NYC Office of the Mayor, 2015a; Philadelphia Managing Director’s Office, 2015).
Recommendation 8: Sustainability plans and actions should include policies to reduce inequality. It is critical that community members from across the economic, social, and institutional spectrums be included in identifying, designing, and implementing urban sustainability actions.
The Importance of Benchmarks and Thresholds
Finding 9: An extensive review of indicators undertaken in this report found very few accepted standards and benchmarks for sustainability assessment among the indicators that were reviewed. Those with specific thresholds were primarily traditional air and water quality standards.
A large share of urban sustainability literature argues that metrics are valuable inasmuch as they help understand and reveal “the state or trend of certain environmental or societal conditions over a given area and a specified period of time” (EPA, 2014a). Accurate data are essential to building sustainability indicators with threshold targets and outcomes. No longer can urban areas depend on hunches or low-level impact actions to make progress toward sustainability. Cities should avoid choosing metrics based on the ease with which a city can make progress in a particular area. Most practitioners do not need another rating system and existing standard indicators should be adopted to the maximum extent possible and as appropriate for the particular characteristics of the urban area (Wilbanks and Fernandez, 2012).
There are many rating systems, but none is commonly accepted, and these systems must continue to evolve in order to be more useful to practitioners. Existing metrics are not common, cannot be shared, and have been developed at different scales. Many existing metrics have weak scientific underpinnings and additional research is needed to assess the relevance and applicability of these indicators. Reaching scientific consensus on indicators is a grand challenge of urban sustainability and worthy of attention. Every indicator must then be connected to both an implementation and an impact statement to garner more support, and engage the public in the process.
Most urban areas lack climate change information at a scale and in a format that is relevant to their region and useful to urban policy makers and community stakeholders. Of the city sustainability plans investigated for this report, few contained regional climate information, suggesting that this information either does not exist or is not easily discoverable and usable. Similarly, most urban areas do not have established and funded mechanisms for updating and revising sustainability plans to reflect changes in climate-related conditions.
Recommendation 9: Cities should adopt comprehensive sustainability metrics that are firmly underpinned by research. These metrics should be connected to implementation, impact, and cost analyses to ensure efficiency, impact, and stakeholder engagement.
The Urgency in Sustainability
Finding 10: While the committee has uncovered numerous successful examples of urban sustainability in a variety of cities, the pace and scope of these actions do not appear to be sufficient to meet urgent global challenges, such as climate change impacts, geophysical events, energy scarcity, increasing population inequalities, health threats, and the increasingly negative consequences of these conditions.
This is a call to action. All three dimensions of sustainability hold serious challenges for urban, regional, and global sustainability. The ongoing long-term drought in Los Angeles and the associated scarcity of both water and energy supplies (due to the energy requirements to transport long-distance water supplies) are prime examples of the challenge of global environmental constraints. Social and economic issues abound across regions and cities. High rates of poverty, housing affordability, unemployment among young and older workers, outmigration of the middle class, the decline of traditional manufacturing industries, and decreased federal spending highlight the challenges facing urban areas. These challenges are exemplified in extreme disparities in socioeconomic status in Philadelphia, outmigration due to deindustrialization in Flint, the loss of the middle class in Pittsburgh due to the decline of the steel industry, as well as single industry collapses in Flint (the auto industry) and Chattanooga (manufacturing) (Bonham and Smith, 2008; Graham, 2015; Greenhouse, 2014).
There are also opportunities to make progress. There is currently a window of opportunity in the form of infrastructure replacement needs throughout the United States, and the integration of risk management and adaptation concepts into suitably designed approaches to addressing these infrastructure problems can yield significant progress toward sustainability.
Recommendation 10: Urban leaders and planners should be cognizant of the rapid pace of factors working against sustainability and should prioritize sustainability initiatives with an appropriate sense of urgency to yield significant progress toward urban sustainability.
An increasing percentage of the world’s population and economic activities are concentrated in urban areas; therefore, cities are central to any discussion of sustainable development. While urban areas can be centers for social and economic mobility, they can also be places associated with significant inequality, debility, and environmental degradation: a large proportion of the world’s population with unmet needs lives in urban areas. Those needs must be met while bearing in mind global constraints. There is no single approach to urban sustainability. However, it is valuable to assess practices being implemented in specific urban and metropolitan regions to determine whether and how they might be adapted and applied in other urban areas. Simultaneous action across multiple dimensions can accelerate the pace and depth of on-the-ground transformations. America’s urban population is expected to increase by 15 percent by 2030. Much-needed investments in our existing infrastructure, in addition to the need to build more urban space for a growing urban population, indicate an urgent need to design and plan for new, as well as existing, cities.
This study provides a paradigm (the urban sustainability roadmap) that incorporates the social, economic, and environmental systems existing in urban areas that are critical in the transition to sustainable metropolitan regions. This roadmap can serve as a starting point for discussion among academics, practitioners, policy makers, civil society, and other stakeholders on how metropolitan areas can transition to sustainability. There are a large number of metrics and indicator systems spanning a variety of spatial scales, and these can be useful when tailored to particular cities and when geared toward four key principles: the planet has biophysical limits, human and natural systems are tightly intertwined and come together in cities, urban inequality undermines sustainability efforts, and cities are highly interconnected. Research and development on the flows between people and places, network characterization, urban metabolism, types of data, and decision-making processes that link across scales can yield further advancements toward sustainability. Similarly, there is a great need for cross-sectoral and multiscale policies and for science-driven approaches, as well as scientifically grounded indicators and metrics for assessment and benchmarking.
What the city profiles collectively show is that there are opportunities for meaningful change that improve the lives, economy, and environment of all types of cities. Constructing a vision is crucial, as is public buy-in and community engagement. We have seen numerous and varied change across all the city profiles—polluted cities transform themselves into green, vibrant places, and cities with failing industries can diversify their economies. Furthermore, managing tradeoffs among the three dimensions of sustainability while aiming to maximize total net benefits relative to costs is an integral part of the sustainability process. While there is no single way to becoming more sustainable, many strategies and successful examples exist that provide valuable lessons from which cities can learn.