Can a City Be Sustainable? (State of the World)

The Worldwatch Institute

• Publisher: Island Press
• Year: 2016
• ISBN:
  9781610917568
• Topic: Architecture
• Subtopic: Architecture générale

Cities are the world's future. Today, more than half of the global population—3.7 billion people—are urban dwellers, and that number is expected to double by 2050. There is no question that cities are growing; the only debate is over how they will grow. Will we invest in the physical and social infrastructure necessary for livable, equitable, and sustainable cities?In the latest edition of State of the World, the flagship publication of the Worldwatch Institute, experts from around the globe examine the core principles of sustainable urbanism and profile cities that are putting them into practice. State of the World first puts our current moment in context, tracing cities in the arc of human history. It also examines the basic structural elements of every city: materials and fuels; people and economics; and biodiversity.In part two, professionals working on some of the world's most inventive urban sustainability projects share their first-hand experience. Success stories come from places as diverse as Ahmedabad, India; Freiburg, Germany; and Shanghai, China. In many cases, local people are acting to improve their cities, even when national efforts are stalled.Parts three and four examine cross-cutting issues that affect the success of all cities. Topics range from the nitty-gritty of handling waste and developing public transportation to civic participation and navigating dysfunctional government.Throughout, readers discover the most pressing challenges facing communities and the most promising solutions currently being developed. The result is a snapshot of cities today and a vision for global urban sustainability tomorrow.

The Urban Climate Challenge

CHAPTER 6

Cities and Greenhouse Gas Emissions: The Scope of the Challenge

Tom Prugh and Michael Renner

Since at least 2008, cities have hosted half or more of the earth’s human beings, a share that continues to grow. Cities also account for more than 80 percent of global gross domestic product (GDP) and about 70 percent of global energy consumption and greenhouse gas emissions. If present trends continue, urban populations are expected to increase to 6 billion by 2045, at which point two-thirds of all people will live in urban environments. These figures suggest that while cities tend to be associated with higher per capita wealth than rural communities, they also account for higher per capita greenhouse gas emissions. In any comprehensive attempt to address climate change, therefore, cities and their inhabitants must play a vigorous and leading role.¹

It is no surprise that cities collectively account for a large share of greenhouse gas emissions, because they concentrate economic activity. However, cities vary widely in their per capita emissions (see Table 6–1), depending upon a wide array of variables that may or may not be under their control. These include climate (which affects heating and/or cooling requirements); location (which helps determine climate and whether a city is a gateway for people and goods via ports and airports); primary sources of energy consumed (hydroelectric power and/or other renewables, coal, nuclear; these often are not under city control); urban form (transport energy use and greenhouse gas emissions are inversely correlated with settlement density, for example); technology (such as the use of methane capture in landfills); and the age, characteristics, and condition of the building stock. Economic factors, such as the wealth and income of residents and the level of economic activity, also play a major role, as does economic structure: urban areas with extensive manufacturing industries have a very different footprint than cities where service activities predominate.²

Tom Prugh and Michael Renner are senior researchers at the Worldwatch Institute and codirectors of the State of the World 2016 project.

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Table 6–1. Greenhouse Gas Emission Baselines for Selected Cities and Years

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Note: Data are not always directly comparable due to differing years and methodologies; they are meant only to give a general sense of relative emissions. Data without a year were provided by ICLEI–Local Governments for Sustainability, with no year specified.

Source: See endnote 2.

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Much is known in broad terms about the major drivers of urban greenhouse gas emissions that can be shaped or influenced by public policy. These include building energy use, transport, the forms of urban development, waste handling and disposal, and deforestation. According to one recent analysis of 274 cities with a total population of 775 million and drawn from all regions and city sizes, four factors—economic activity, transport, geography, and urban form—account for 37 percent of the variability in urban direct energy use and 88 percent of the variability in urban transport energy use.³

To some extent, the driver categories overlap and influence one another. For instance, modes of transportation and settlement patterns shape each other over time; favoring automobiles and the roads they require tends to encourage sprawl, while more-compact patterns obviate automobile use for many city residents and also enable more-efficient public transport. In addition, generally speaking, all of these factors and the greenhouse gas emissions associated with them can be said to be direct or indirect functions of lifestyle.

The major common thread running through the categories is energy use: how much and of what kind. Many cities have little control over their energy supplies (although there is a recent trend toward remunicipalization; see Chapter 16). However, nearly all cities have numerous options and room to maneuver on the demand side of the energy equation. It is largely because of their ability to influence or control so many decisions—about building efficiency, transport modes, development patterns, and even, to some extent, the consumption practices of city dwellers—that cities are among the key actors in the effort to constrain global energy use and greenhouse gas emissions.

Motives for City-Level Action

Urbanites increasingly realize that climate change poses tremendous challenges and, in more than a few cases, may even threaten cities’ continued habitability. If climate change is allowed to proceed unchecked, urban life will be conditioned by sea-level rise, storms, flooding, droughts, and heat waves. These phenomena will claim growing material and financial resources in response to disasters or due to mitigation efforts, while undermining urban economies, destroying jobs, and imposing rising health costs. Beyond the direct climate consequences for cities are the effects on the inflow of food and other natural resources on which cities depend. Climate impacts are added, and often linked, to many other, longstanding sustainability concerns, such as the threat of air and water pollution or hazardous waste flows. These affect not just the health of the urban population, but also cities’ livability and attractiveness to businesses and to visitors.

Cities also are discovering that other drivers and concerns may justify and stimulate action toward sustainability, including economic development and innovation through various “greening” measures. Creating and securing local jobs is a key concern of any city administration. Traffic congestion increases the costs of business, wastes fuel, and pollutes the air, while measures to reduce traffic and to shift from cars and trucks to public transit have multiple benefits. Concerns about the security of energy supplies—including worries about volatile prices (and the risk of growing energy poverty)—may lead mayors and city councils to procure locally produced renewable energy supplies and require more energy-efficient buildings. Cities suffering from deindustrialization or dramatic changes in their economic base may seek to revitalize former industrial areas through efforts that can be focused on sustainability measures. Well-designed policies can address both socioeconomic and environmental problems, increasing the cohesion between these goals and reducing conflicts and contradictions.

Elevators to a futuristic-looking RandstadRail light rail station in The Hague, The Netherlands.

Michael Renner

Spurred by these motivations and by the disappointingly slow progress toward addressing climate change at the national and international levels (notwithstanding the climate agreement reached in late 2015 in Paris), for some years now, cities have increasingly recognized their role in contributing to the global burden of greenhouse gas emissions and accepted their responsibility for reducing it. More and more cities around the world are taking action to address the climate crisis and other environmental challenges, in the hope and expectation that action will be swifter and more meaningful at the local level.

Growing numbers of cities have pledged themselves to climate commitments as well as to broader sustainability goals and are banding together with like-minded counterparts in peer-to-peer networks to facilitate and reinforce movement toward sustainability. The C40 Cities Climate Leadership Group (which, as of 2015, had expanded to over 80 cities) is a prominent network that has pledged to take action to reduce greenhouse gas emissions. Other noteworthy initiatives and groupings are pursuing eco-mobility, renewable energy, green buildings, zero waste, and the like. The Compact of Mayors, launched at the 2014 United Nations Climate Summit, is the largest coalition of city leaders addressing climate change. ICLEI–Local Governments for Sustainability has a long track record of working with more than 1,000 cities around the world as well as with international agencies such as UN-Habitat. Other organizations with narrower geographical focuses, such as STAR Communities and the Urban Sustainability Directors Network (both in North America), work to support and assist cities toward their sustainability goals.

These initiatives for collaboration and mutual support have begun to bear fruit in the form of encouraging steps toward concrete action. C40’s Global Aggregation of City Climate Commitments details how 228 cities (with a combined population of 439 million people) have set climate reduction goals or targets that would, if achieved, lead to significant reductions in annual emissions compared with a business-as-usual scenario. To date, the reductions are stated in terms of emissions “savings” from business-as-usual scenarios that assume ongoing growth in population and economic activity, rather than in terms of their effect on atmospheric greenhouse gas concentrations. It appears that these reductions alone would not actually reduce the global rate of emissions but only slow the rate of continued increase; moreover, most of the commitments are set for 2020 or 2050. However tentative and conditional, these commitments nevertheless are vital as public acknowledgments of the climate challenge and the urgent need to address it. They constitute crucial underpinnings for countries’ Intended Nationally Determined Contributions (INDCs)—the national greenhouse gas reduction pledges embodied in the Paris Agreement.

Cities’ Powers to Act

Although cities across the world face many similar challenges, their particular circumstances, needs, and capacity to act—which are typically a product of their historically grown structures and their political cultures—can vary enormously. The shares of cities’ greenhouse gas emissions attributable to each sector, for example, differ widely from one city to another, and each of the major drivers of urban greenhouse gas emissions has its own suite of shaping forces and policy options. Plans tailored to each city’s circumstances, while sharing certain broad features, therefore will be highly individualistic.⁴

Depending on an urban area’s specific economic base and profile, the most effective focus for emissions reductions and other pro-sustainability changes may be in the industrial sector, in transportation, or perhaps in the built environment. Cities with pollution-intensive industries, such as refineries or heavy manufacturing, face a much greater challenge than those that are more service-oriented. (Such factors need to be accounted for in setting fair reduction targets for individual cities and nations, for the simple reason that, in a g...