The Social and Sustainable Use of Space

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NTRODUCTION

Although urban localities occupy only a minute part of the Earth’s surface, there are huge social and environmental implications to where, why and how cities are built and land is incorporated into the urban make-up. This part begins with a broad overview of the relationships between urban growth and global environmental change. In Chapter 8, Sánchez argues that a better understanding of these interactions requires, above all, a more comprehensive vision of urban sustainability. He notes that fragmented approaches to urban planning have hampered effective solutions. Similarly, he points out that the perception that the negative consequences of global environmental change will occur in the long term, and thus do not require immediate attention, is also misleading. Local processes that affect or are being affected by regional and global biophysical processes also require actions (mitigation and adaptation) in the short term.

To help stimulate a broader approach, Sánchez offers a multidimensional conceptual scheme for the study of the interactions between urban areas and global environmental change (GEC). He shows how the biophysical system results from interactions between regional and global biophysical and chemical processes and local, regional and global socioeconomic and geopolitical development. He then examines in greater detail how urban areas interact with GEC through land cover and climate changes. This discussion depicts an alarming scenario of vulnerabilities, especially for developing countries and the poorer segments of the urban population, urging not only more effective integrated action but also a greater focus on equity issues.

Climate change is particularly critical for coastal areas, which tend to have more fragile ecosystems and yet be more urban than inland areas. Overall, low elevation coastal zones contain some 2 per cent of the world’s land and 10 per cent of its population. In Chapter 9, McGranahan, Balk and Anderson focus on urban settlements in such areas and the risks from fl ooding and storm damage that climate change poses for their growing populations. Though mitigation of climate change may be the best means of reducing such threats, urban settlement is highly path-dependent;

thus urban coastal settlements established in the past and present are likely to attract more urban coastal settlement in the future. Out-migration from some of the most

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threatened coastal regions may eventually be called for. Timely measures to prevent urban development in risky locations are also critical.

Dense littoral populations can also be a burden on coastal ecosystems, many of which are already under stress, and the loss of ecosystem services can make urban settlements more prone to disaster. Many of the risks from climate change could be reduced by more appropriate land-use patterns and regulation of residential and commercial activities. In many cases, there may be measures that can address present problems while also providing a means of adapting to climate change. These are an obvious place to start, even if such coincidences of interest are unlikely to be suffi cient to form the basis for all of the adaptive measures needed.

The geographical setting and ecological resources of urban locations affect the success of individual urban centres, and, in an increasingly urban world, the location of urban populations also has environmental signifi cance at larger scales, including globally. In Chapter 10, Balk, McGranahan and Anderson estimate the rates of urbanization and urban growth by ecological zone. They fi nd that, while continental, regional and country-level views are signifi cant to the understanding of environmental processes, ecological zones are more environmentally relevant. The latter take on special signifi cance in light of changing environmental conditions and the possibility that urbanization trajectories will come into confl ict with these environmental shifts.

While coastal zones are more urbanized than other zones, and home to the largest urban areas of most nations, other zones, such as inland water and dryland areas, are also important and vulnerable and are home to large numbers and growing shares of urban population. Future urbanization, in Africa and Asia in particular, is expected to be high in many of these other zones, as well, raising the bar for environmentally sustainable development under varying conditions of resource scarcity.

Chapter 11 looks at urban sustainability from the standpoint of one of the most talked-about features of modern city growth: urban sprawl. Hogan and Ojima review the debate from the perspective of the challenges that sprawl raises for the sustainability of expected urban growth in coming decades. Originating as an aspect of suburbanization in North America during the post-World War II years, sprawl became a volatile political issue by the end of the 20th century. Its appearance in Europe – where compact cities have a long tradition – and, especially in developing countries, is related to contemporary lifestyles and does not bode well for harmonizing environmental quality with population concentration.

Criticism of sprawl has been strong in terms of both social and environmental consequences. Sprawl is associated with longer daily travel times and less family time, a health burden that includes greater stress, pollution from increased traffi c, loss of green space, increased water use, and ecosystems compromised by fragmentation.

The authors discuss the methodological diffi culties of measuring sprawl; review related polemics on compact versus dispersed cities; and emphasize the importance of the morphology of urban growth. Form, as well as size, is held to be a crucial component of urban sustainability. The authors conclude that not all forms of dispersed urbanization can be considered sprawl and that other forms of dispersion are still insuffi ciently understood.

Overall, it seems clear from these different contributions that, although most interest has so far been focused on the ecological footprint of cities in terms of their production and consumption patterns, preparing for a sustainable urban transition will require much greater attention to where and how cities grow and how they are

THESOCIAL AND SUSTAINABLEUSE OFSPACE 147 administered. A new vision, inspired by both global concerns and local perspectives such as those outlined in this part, will have to emerge and, in turn, spawn better informed and more participative regional responses to the challenges of rapid urban expansion.

8

Urban Sustainability and Global Environmental Change:

Refl ections for an Urban Agenda

Roberto Sánchez-Rodríguez

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NTRODUCTION

The destiny of today’s societies is increasingly tied to the evolution of their urban areas. Fostering balanced growth in dynamic urban areas is undoubtedly challenging.

Various contradictory needs and actions affect the daily functioning of cities and determine the types of urban space created, as well as their environmental impacts.

Rapidly growing cities in poor countries are the most affected by the diffi culties of achieving sustainable urban growth. Unemployment and underemployment, environmental degradation, defi ciencies in urban services and housing, deterioration of existing infrastructure, lack of guaranteed access to the natural resources vital to urban life, and an alarming increase in violence are but a few of the problems they face.

All of these issues are aggravated by the rapid growth of populations and urban spaces, as well as by imbalances in urban structure and accumulated defi cits in the construction, expansion and operation of public services. Economic and fi nancial crises further exacerbate these problems. The overall result has been the formation of fragmented and segregated urban spaces that increase social exclusion and defi ciencies in the functioning of urban areas while also aggravating environmental problems (Lopes de Souza, 2001; Pirez, 2002; Moser and McIlwaine, 2005).

During the last 15 years, urban sustainability efforts have sought to balance three critical functions of urban areas: as engines of economic growth, as loci of

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improved social wellbeing and as agents of environmental change. For the most part, however, urban sustainability continues to be more a normative ideal than an operational reality. Most approaches emphasize the economic aspects (urban areas as centres of wealth production), giving limited attention to environmental protection and social wellbeing.

A more effective approach to urban sustainability should recognize, and somehow deal with, the complexity of the dynamic interactions among socioeconomic, geopolitical and environmental processes at local, regional and global levels.

Current approaches to sustainable development that tend to consider urban issues in a fragmented manner should be replaced with multidimensional perspectives capable of generating an integrated perspective of complex and dynamic urban realities (Pelling, 2003).

Fragmented approaches are frequently the result of the technical exercise of planning, of simplifying complex urban realities in order to facilitate the design and implementation of actions aimed at the resolution of immediate problems, such as in public services, housing, transportation, urban economy and environmental pollution. This fragmented vision overlooks the wide range of multidimensional social, economic, political, cultural and biophysical interactions behind each urban problem. Issues of natural resource supply, ecological services and environmental pollution cannot be considered in isolation from their broader social, economic and cultural contexts (Bryant and Wilson, 1998; Gibbs and Jonas, 2000).

This chapter seeks to contribute to an integrated multidimensional vision of urban sustainability and to a better understanding of the interactions between urbanization and global environmental change (GEC). A central argument made here is that urban sustainability in the 21st century requires looking beyond the local scale in order to foster a dynamic perspective of the interactions between the local, regional and global biophysical and social processes that are generated by, and that affect, urban areas.

One specifi c goal of this chapter is to help change the perception that, since the negative consequences of GEC will occur in the long term (25, 50 or 100 years from now), they do not require immediate attention. Such a view fails to recognize that the local processes that are affecting and being affected by regional and global biophysical processes also require actions (mitigation and adaptation) in the short term to reduce their negative consequences. Since such actions are linked both directly and indirectly to current urban and environmental problems, investments in solving them could help to mitigate or adapt to the negative consequences of GEC – if their design took into consideration their interactions with regional and global processes. The good news is that many of those actions do not require additional costs to the programmes currently focusing on planning for the urban future.

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The negative effects that urban areas have on the global environment have drawn considerable attention, especially in regard to the effects of greenhouse gas emissions and the so-called ‘heat island effect’ on climate change (IPCC, 2001). A series of international, regional and local initiatives have prioritized the reduction of greenhouse gas emissions in urban areas. However, the biophysical and chemical processes associated with GEC also have negative but less-recognized impacts on urban areas.

Figure 8.1 presents a graphic representation of a conceptual scheme for the study of the interactions between urban areas and global environmental changes.

The scheme is based on two premises. The first is that urban systems result from alterations made to the landscape as a result of social processes expressed in physical space by the built environment. The impacts of the urban system on the biophysical system, or those of the biophysical system on urban space, will be different, depending on the type of space created (for example a well-serviced area as opposed to a slum area). The type of built landscape and the social groups occupying it have different capacities to cope with, adapt to and resist the impacts of GEC or to generate those impacts. This distinction is important when addressing equity issues in urban sustainable development. Moreover, the biophysical system is, in reality, the result of interactions between regional and global biophysical and chemical processes and local, regional and global socioeconomic and geopolitical ones. For instance, alterations to the water or carbon cycle – responsible for climate change and other aspects of GEC – are the result of such interactions.

The second premise is the recognition of a bidirectional relationship between urban areas and biophysical systems, as shown by the short light-grey arrows in Figure 8.1. One side depicts the manner in which the urban system impacts on the biophysical system. Greenhouse gas emissions of urban origin – from transportation, industry and services – and heat emissions, including heat islands, are clearly responsible for this impact. Other factors, such as changes in land use and land cover directly or indirectly caused by the urban system, also impact on the biophysical system but receive less attention. The demand for construction materials, food, energy, water and other natural resources cause changes in land use and land cover. For example, the high urban demand for wood and food has caused deforestation and the associated increases in CO₂ emissions, while the demand for water produces alterations in the water cycle of large areas. The other short light-grey arrow illustrates how the biophysical system impacts on the urban area.

Natural disasters are one of the most visible results, but there are other impacts on urban form and function (the urban economy and social activities) and on health that are relevant to daily urban life and future urban sustainability.

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Figure 8.1 also presents a second bidirectional fl ow (the dark-grey arrows) between the urban system and the biophysical system. It illustrates the dynamic nature of these non-linear processes. Society, like nature, often has unexpected responses to sudden shocks. Cities are complex systems where unexpected reactions to extreme events are part of a wide array of feedback loops that result from such interactions with GEC. This second group of impacts occurs as a consequence of the fi rst.

For example, increases in temperature (heat waves) can cause a large increase in energy use in many urban areas, thus elevating the emission of greenhouse gases and the impact on the biophysical system. Extreme climatic events, such as fl oods or droughts, can intensify migration to urban areas, resulting in changes to land use and land cover. These changes, in turn, cause a new series of impacts on the biophysical system and subsequently on urban areas.

The interactions between GEC and urban areas can be classifi ed into two main broad areas: land-use and land-cover change, and climate change. These are examined briefl y in the following sections.

Figure 8.1 The interactions between urban areas and global environmental change:

A conceptual framework

Source: Sánchez-Rodríguez et al (2005).

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Cities are increasingly the sites of most economic growth, a fact that has been accentuated by globalization. This concentration of economic activity is associated with rising incomes and consumption patterns. Both of these consequences tend to increase pressure on natural resources at the regional and global levels. Although urban production and consumption processes may originate in an urban area, their impacts are usually not confi ned within the city’s boundaries. Urban dynamics have the potential to affect social, cultural, economic and ecological processes in lands that are both near and distant from the urban core (Eaton et al, 2007).

To fulfi l their needs, urban systems have ‘zones of infl uence’ well beyond the immediate urban area. Cities depend on vast resources for the supply of critical ecological services, from the supply of inputs (for example food, energy, water and building materials) to the provision of ecological services (for example wildlife corridors, microclimate and buffer areas to protect against fl ooding). Outlying areas also suffer the same negative consequences as urban areas (for example pollution, urbanization pressures and land-use changes, and degradation of natural resources).

‘Peri-urban areas’ satisfy many of these needs and also provide essential services to both the urban and outlying areas.¹ In the most general sense, the development of peri-urban areas involves a complex adjustment of social and ecological systems as they become absorbed into the sphere of the urban economy. Land-use and land-cover changes are associated with the provision of these ecological services and natural resources (Tratalos et al, 2007). Thus GEC and globalization affect the pool of natural resources and ecosystem services upon which urban systems rely (the bidirectional arrows in Figure 8.1).

The rapid rate of change in rural and peri-urban areas demands greater attention in order to understand how urban–rural land-use dynamics will be affected by different levels of GEC and the social responses to them. Globalization is not only a driving force in the growth of cities; at the same time, it facilitates the extension of a city’s area of infl uence over larger geographical areas and even across national boundaries. Studies on urban metabolism have documented fl uxes of energy, water, food and construction materials. However, little attention has been paid to the locus of those resources or to the environmental and socioeconomic consequences of urban growth at the local, regional and global levels, including the changes in the landscape.²

An additional concern for the future is that the rapid transformation of the rural and peri-urban areas providing such services could change them to urban or other land uses without due consideration of their critical role for the long-term sustainability of the city or for the Earth’s ecosystem. The extensive transformation of wetlands or forests near urban areas, for instance, has signifi cant consequences at the local level (on microclimate, the hydrological cycle, habitats and biodiversity, and so on) and affects basic biophysical processes at the regional and global levels

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(carbon and hydrological cycles and biodiversity). Ultimately, such alterations impact on GEC.

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The transformation of human societies has always been intimately related to climate.

The development and collapse of civilizations have strong links with environmental management and, in particular, with climate management (Diamond, 2005).

For centuries, technological advances have gradually transformed the capacity for adaptation to adverse climate conditions, particularly evidenced in the form and location of human settlements (housing and urban space). Changes have been particularly dramatic in the last century: the adoption of technology such as air-conditioning and central heating has facilitated the prioritization of aesthetics over more functional aspects in architecture and urban design and adaptation to climate.

Changing cultural patterns, infl uenced by the growth of capitalist consumer societies, and by their rapid spread throughout the ‘global society’, have further induced the abandonment of traditional knowledge on how to adapt to local climate conditions. These new patterns are based on signifi cant energy costs (for example air-conditioning or new materials) and new architectural and urban forms.

Climate change and climate variability often aggravate the defi ciencies of poor adaptation to climatic conditions and increase dependence on artifi cial coping mechanisms.

Direct climate impacts, however, are not the only component of GEC that shape the form and growth of the built environment. Indirect changes can also have an effect. Sea-level rise in coastal areas has an impact on the shape and form of urban areas, as well as on their vulnerability to inundation. Better knowledge and understanding of these interactions would provide useful information to national and local decision-makers about the way that biophysical processes shape the construction, form and function of the built environment. Such knowledge would be useful in infl uencing growth and sustainable development policies for urban areas in both rich and poor countries, and also assist them in adapting to the potential negative consequences of climate change.

The effect of an increase in the temperature of an urban area in comparison to its surroundings is a particularly important component in the relationship between urban areas and climate (Rosenzweig et al, 2005). The size of the urban centre and its type of urbanization and land use are some of the factors that determine the urban heat island (UHI) effect. As population centres grow in size, from village to town to city, they tend to have a corresponding increase in average temperature – between 2 and 6°C hotter than the surrounding countryside – thereby increasing the demand for air-conditioning. Moreover, as a result of UHIs, monthly rainfall is greater in upwind parts of the urban area compared to areas downwind.