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1、THE ENVIRONMENTAL CRISIS AND SUSTAINABLE DEVELOPMENT 1 INTRODUCTION The subject matter of this book is the planning and design of ecologically sustainable cities. It is concerned with the process of structuring public space in the city at a time when the global environment appears increasingly fragi
2、le. Any discussion of city planning and urban design, which does not address environmental issues, has little meaning at a time of increasing population pressures on a declining natural resource base, widespread ecological destruction, increasing pollution, ozone layer depletion and climate change.
3、The long-term survival of the planet as a vehicle for sustained human occupation in anything other than a degraded lifestyle is in some doubt: in these circumstances any discussion of the aesthetics of city planning in a pure or abstract form unrelated to environmental concerns could be described as
4、 superficial. Architecture and its sister art, urban design, are said to consist of Commodotie, Firmness and Delight (Wotton, 1969). One aspect of Commodotie in any urban development is sustainability that is, a development which is non- damaging to the environment and which contributes to the citys
5、 ability to sustain its social and economic structures. The pursuit of sustainable city structures presupposes also the development of a built environment of quality: one that Delights. Environmental quality in the city is, in part, determined by aesthetic values. This book aims to explore the probl
6、em of defining quality, the poetry of civic design, but seen against a backcloth of the current concerns about the environment and the imperative of achieving ecologically sound development. The theme of this book is the Green Dimensions of urban design: the second half of its title was chosen with
7、care. Nothing, as far as we know, in the physical universe is permanent; nothing lasts forever. All things have a beginning and an end, including vast cultures, their great empires and cities. Sustainable development is a concept with 1 strict temporal limits: sustainable urban form a mere chimera,
8、a mirage that disappears over the horizon on approach. A degree of sustainability is all that can be achieved in any set of circumstances. It seems appropriate, therefore, to limit a study of sustainability to its dimensions: those factors that, from time to time, appear relevant. Some forms of deve
9、lopment will probably be more sustainable and long-lasting than others. There is no authorative research on sustainable urban forms, only informed speculation about the path to be taken. This is a further reason for the tentative title of the book. It would appear that the Post Modern agenda of the
10、New Urbanists is compatible with much of the theory of sustainable development, particularly those theories of sustainable development of the paler green hue. The current preoccupations of many urban designers are with the vitality and identity of urban areas, the quality of urbanity and the compact
11、 city, urban forms of human scale, which are less dependent upon the use of finite resources while respecting and conserving the natural environment. While there is a general consensus on the features of a sustainable development agenda amongst many working in the field of urban design, nevertheless
12、 there are differences in emphasis, (Carmona et al., 2003). Over a decade ago, Calthorpe (1993) in the USA outlined his principles for the Transit-Oriented-Development: an agenda that many in this country could still accept as a general guide. In summary, the principles of Transit-Orientated Develop
13、ment are: (1) Organize growth on a regional level so that it is compact and transit-supportive. (2) Locate commercial, housing, jobs, parks, and civic uses within walking distance of transit stops. (3) Design pedestrian-friendly street networks which directly connect local destinations. (4) Housing
14、should be a mix of densities, tenure and cost. (5) Sensitive habitat, riparian zones, and high-quality open space should be preserved. (6) Public spaces should be the focus of building orientation and neighbourhood activity. (7) Encourage infill and redevelopment along transit corridors within exist
15、ing neighbourhoods. This then, is the basic urban design agenda, compatible with sustainable development ideas, but is it sufficient for achieving that aim? THE ENVIRONMENTAL MOVEMENT It has been suggested that the publication of Silent Spring by Rachel Carson in 1962 was the start of the modern env
16、ironmental movement (Dobson, 1991). However, the roots of environmentalism may be much deeper. Farmer (1996) has traced the development of Green Sensibility in architecture back to folk buildings and the cult of the cottage through the nineteenth century in the writings of Ruskin, the work of the Ar
17、ts and Crafts movement to the twentieth century and the organic ideas in Modern Architecture. The planning profession could also cite its list of planners with green credentials. Amongst these father figures of the planning world would be Geddes (1949), Howard and the Garden City U R B A ND E S I G
18、N :G R E E ND I M E N S I O N S 2 Movement (1965), and Mumford (1938) with his analysis of the Rise and Fall of Megalopolis. No doubt other disciplines could legitimately cite their own lists of people with deep concerns for the environment, many of them working long before the term sustainable deve
19、lopment was coined. While it is not the intention to downgrade these fine scholarly traditions, nevertheless, for the purpose of this study, and for convenience, the beginnings of the modern environmental movement will be placed in the 1960s. The mood of environmentalism quickened with Rachel Carson
20、s analysis of the inevitable damage caused by large-scale and indiscriminate use of chemical pesticides, fungicides and herbicides. Carsons influence was widespread, affecting pressure groups such as Friends of the Earth, in addition to the stimulus she gave to the development of green politics and
21、philosophy. From the USA, Ian McHarg, the Scottish e migre , published his seminal work Design with Nature in 1969, seven years after Carsons warning cry. McHargs ecological thesis spans the disciplines of landscape, architecture and planning: he is one of the founding fathers of sustainable develop
22、ment. McHarg argued that human development should be planned in a manner that took full account of nature and natural processes. Design with Nature in addition to articulating a philosophical position also provided a technique for landscape analysis and design using overlays, a technique which now f
23、orms the basis of GIS, Geographic Information Systems, an important tool for current planning and design. While McHarg was writing in the 1960s, the thrust of his argument still applies today in the twenty- first century. It is their (the merchants) ethos, with our consent, that sustains the slumlor
24、d and the land rapist, the polluters of rivers and atmosphere. In the name of profit they pre-empt the seashore and sterilise the landscape, fell the great forests, fill protective marshes, build cynically in the flood plain. It is the claim of convenience or its illusion that drives the expressway
25、through neighbourhoods, homes and priceless parks, a taximeter of indifferent greed. Small is Beautiful by Schumacher (1974) is another milestone in the analysis of the causes of environmental problems and in the development of green principles. One cause of environmental problems according to Schum
26、acher is the notion that we can continue to produce and consume at ever-increasing rates in a finite planet. Schumacher warned that the planet which is our stock of capital is being threatened by overproduction: in effect, the human race is consuming its capital at an alarming rate, endangering the
27、tolerance margins of nature, and so threatening the life support systems that nurture humankind. A further landmark in green analysis was The Tragedy of the Commons (Hardin, 1977). Hardin argued that if everyone maximized his or her own gain from commonly held property, whether land, sea or air (the
28、 commons), the result would be the destruction of those commons. Where populations are comparatively small the commons are not under great threat. With rising world populations, the commons now under threat include the air we breathe, the ozone layer that protects us from the suns rays, and the ecol
29、ogical systems that deal with the waste we cause. How far The Limits to Growth (Meadows et al., 1972) for the Club of Romes Project on The Predicament of Mankind progressed the aims of the environmental movement is problematical. It attempted to plot the T H EE N V I R O N M E N T A LC R I S I SA N
30、DS U S T A I N A B L ED E V E L O P M E N T 3 depletion of resources and to warn of the danger of exponential growth, to the ultimate destruction of a global environment fit for human occupation. The book has been described as mechanistic and non-scientific. It has also been criticized for overstati
31、ng the case, therefore damaging the environmental or green cause. To some extent these criticisms have been addressed in Beyond the Limits (Meadows et al., 1992). The Limits to Growth did attempt, however, to study some aspects of the global environment holistically, concentrating on linkages and ad
32、opting a systems approach to environmental analysis, all being common features of a green method. THE SKEPTICAL ENVIRONMENTALIST The publication by Lomborg, in Danish, of his book, Verdens Sande Tilstand (1998) later translated into English as The Skeptical Environmentalist (2001) was a further land
33、mark in the environmental debate. According to Lomborgs assessment, conditions on earth are generally improving for human welfare: furthermore, future prospects are not nearly as gloomy as environmental scientists predict. Those working in the field of sustainable development cannot ignore Lomborgs
34、thought-provoking analysis, even though most reputable environmental scientists have rebutted his complacent view of the global environment (see Bongaarts, Holdren, Lovejoy and Schneidr in Scientific American, January, 2002). Like Meadows in his Limits to Growth, Lomborg may have overstated his case
35、. Unfortunately, his thesis has given credence to the views of those advocating an environmental free for all, particularly those to the right of American politics (see Bush bending science to his political needs; Guardian, 19th February, 2004). POPULATION An important contributory factor affecting
36、the deterioration of the environment is population growth. According to Bongaarts (2002), Lomborgs assertion that the number of people on this planet is not the problem, is simply wrong. The population of the planet was approximately 0.5 billion in the mid-seventeenth century. It was then growing at
37、 approximately 0.3 per cent per annum, which represented a doubling of population every 250 years. By the beginning of the twentieth century, the population was 1.6 billion but growing at 0.5 per cent per annum, which corresponds to a doubling time of 140 years. In 1970, the global population was 3.
38、6 billion, with a growth rate of 2.1 per cent per annum. Not only was the population growing exponentially but the rate of growth was increasing. From 1971 to 2000 the population grew to about 6 billion, but the growth rate fell to 1.5 per cent per annum. This change in population growth rate is a s
39、ignificant improvement and means a reduction in the rate at which total world population grows. The population growth rate is expected to fall further to about 0.8 per cent per annum by 2030. Despite this fall in population growth rate, the absolute growth will remain nearly as high as levels in the
40、 last decades of the twentieth century, simply because the population base rate keeps expanding: the global population is expected to be about U R B A ND E S I G N :G R E E ND I M E N S I O N S 4 8 billion by 2030 and to reach about 10 billion by 2050. These global figures mask details of unpreceden
41、ted demographic change, which are highly significant for the impact they may have on the environment. The worlds poorest nations of Africa, Asia and Latin America have rapidly growing and young populations, while in the wealthy nations of Europe, North America and Japan, population growth is zero or
42、 in some cases negative. By 2030, over 85 per cent of the worlds population will live in these poorer nations of the developing world. Three- quarters of global population growth occurs in the urban centres of these poorer nations, and half of this increase is by natural growth within cities. This u
43、rban growth in, and rural-urban migration to, the cities of the poor South is occurring in a context of far higher absolute population growth, at extremely low income levels, very little institutional and financial capacity, and few opportunities to expand into new frontiers, foreign or domestic. Wh
44、ile urban poverty exists and is indeed growing in all cities of the world, it characterizes aspects of the rapidly growing cities of the developing countries. There, urban poverty disproportionately affects women and children; fuels ethnic and racial tensions; and condemns large sections, and someti
45、mes the majority of urban dwellers to a downward spiral of marginalization, social and economic exclusion and unhealthy living environments (United Nations, Habitat, 2001). Over 1 billion people live in absolute poverty, living on less than $1 per day. A total of 420 million people live in countries
46、 that no longer have enough cropland on which to grow their own food, and 500 million people live in regions prone to chronic drought: by 2025, this number is likely to be 2.4 to 3.5 billion people. Clearly, population pressures will induce migratory movements throughout the world, so that in Europe
47、 including Britain we can expect to see a continuing influx of economic migrants: some but not all in this country would see this immigration of young economically active people as essential to sustain our aging population (Observer, 25 January, 2004). Such population movements will not be without c
48、onflict. Poverty and environmental degradation are closely interrelated. While poverty results in environmental stress, the major cause of environmental deterioration is an unsustainable pattern of consumption and production, particularly in the industrialised countries, which aggravates poverty and
49、 imbalances (UN, 1992b). The cause of the problem does not lie in the poor South, but in the over-consumption in the rich North: over-consumption being a euphemism for the much shorter and more accurate word greed, as used by McHarg. Nevertheless, a reduction in population growth rates through education and family planning is of great importance in establishing a sustainable future for humankind: alone, however, it is insufficient. It is worth noting that one child born in Europe or the USA will use the same resou