The issue of sustainable urban development has concentrated the minds of governments and research organizations around the world. Cities have been seen as the cause of environmental degradation and resource depletion, casting an ecological footprint across the globe, far beyond their immediate regions. More often than not, cities are seen as problematic with congestion, pollution, poor housing, collapsing infrastructure, crime and poverty. Yet it is cities that drive economies, and it is within them that innovation occurs and the majority of global output is produced.
Over the past five years the world has seen a 2.5% growth in urban population, but that [31](1. scatters 2. stands 3. varies) between the more developed regions (0.7%) and the less developed regions (3.3%). In 1999, 47%, or 28 billion, of the world’s population lived in cities, and this is set to increase [32](1. by 2. to 3. with) around 70 million people each year. The expectation is that by 2030 nearly 5 billion (61%) of the world’s 8.1 billion people will live in cities. Of the urban population, for every one person now living in cities in developed countries, there are two in the cities of the developing world. Within 30 years this proportion is predicted to rise to 1:4, indicating that 90% of the growth in urbanization will be in developing countries.
In these countries the expansion of urbanization is [33](1. controlling 2. growing 3. occurring) on an unimaginable scale. Very large cities the megacities with populations of over 10 million people are becoming commonplace. New York and Tokyo were the only megacities in 1960, but by 1999 there were. In another 15 years projections suggest there will be at [34](1. largest 2. least 3. most) 26 such cities, 22 of which will be in developing countries, and 18 of these in Asia. However, the most aggressive growth [35](1. Appears 2. Continues 3. Corresponds) to be in the cities of between 1 and 10 million. In 1990, we had 270 million cities; by 2015, various predictions show that there may be between 358 and 516 of these cities.
It is questionable whether these statistics themselves necessarily represent a problem. It is true that the [36](1 . better 2. more . very) size of the cities and the high proportion of the world’s population living within them will inevitably intensify problems, which will include the intensive use of resources such as land, water and energy, the overstretching of infrastructure, poor sanitation and health, and social and economic inequalities. The more serious problem, however, is concerned with [37](1. affluent 2. broad 3. simple) lifestyles and wasteful use of land, both in developed and developing countries, which result [38](1. as 2. in 3. to) a disproportionate use of resources and urban forms that are often unsustainable. For example, commercial enterprises outside cities such as the ubiquitous shopping mall are likely to cause most waste, pollution and harmful emissions. Also the lifestyles of those living in low-density suburban areas on the periphery will be responsible [39](1. by 2. for 3. to) the consumption of more resources than those with similar incomes living in cities.
Cities may have problems, but they are not necessarily a problem in themselves. According to some urban planners in England, it is the ‘failure of effective governance within cities that explains the poor environmental performance of so many cities rather than a [40](1.active 2. exceptional 3. inherent) characteristic of cities in general.’ The manipulation of urban form, and the provision of better forms of governance, may go some way to overcome city problems. [41](1. Because of 2. Despite. Instead of) many problems, the fastest growing cities in developing countries have benefits for those living there. They can provide ‘enhanced opportunity for millions of people’ and ‘refuges from a stifling, restrictive rural life’ that may no longer be economically sustainable. The sheer vitality and numbers of people and ideas tend to change attitudes and lifestyles, and lead to higher [42](1. aspirations 2. levels 3. means) to improve standards of living. How, then, does this tendency relate to sustainable development and sustainable urban form?
There is a strong [43](1. barrier 2. force 3. link) between urban form and sustainable development, but it is not simple and straightforward. It has been suggested that a sustainable city must be of a form and scale appropriate to walking, cycling and efficient public transport, and with a compactness that encourages social interaction. Some other proponents have suggested forms with large concentrated centers, those with decentralized but compact settlements linked by public transport systems, or those with a set of self-sufficient communities based on development strategies [44](1. for 2. On 3. To) dispersion.
In existing cities, the concept of compactness arises through processes that intensify development and bring in more people to revitalize them. The ideas behind the compact city are an important strand in the attempt to find sustainable urban forms, with the belief that compactness will result in reductions in travel [45](1. demands 2. distances 3. opportunities) and thus vehicle emissions, and that the high densities can create greater viability for service provision, public transport, waste disposal, healthcare and education.
The vision of the compact city has been dominated by the model of the densely developed core of many historic European cities. These are a great attraction not just to architects, planners and urban designers, [46] (1. and 2. but 3. or) to countless tourists who flock to see them. They are seen, often by those from outside, as ideal places to live and experience the vitality and variety of urban life. The danger is that it is a romantic vision, one which assumes a golden age that can be recaptured through urban form, leading to a sustainable and benign civility. Perhaps it is not [47](1. believable 2. interesting 3. Surprising) that the strongest advocate for the compact city has been the European Community.
However, the compact city policies proposed so far have been based more in theory than in practice, and the arguments are contentious. The theory is to an extent based on the assumption that restrictions on land use will help to concentrate development and lessen the need to travel, thus [48](1. generating 2. increasing 3. reducing) vehicle emissions. The promotion of the use of public transport, walking and cycling is often cited as a solution. Further reductions of harmful emissions might also result from more energy efficient land use planning, combined power and heating schemes, and energy efficient buildings. It is also argued that higher densities may help to make the provision of amenities and facilities economically viable, [49](1.blocking 2. enhancing 3. reducing) social sustainability.
But on the down side, the compact city may become overcrowded and suffer a loss of urban quality, with less open space, more congestion and pollution, and may simply not represent the sort of environment in which the majority of people would wish to live if they had the [50](1.choice 2. interest 3. right).
Thus, the compact city may have both positive and negative aspects as one style of sustainable urban forms. Furthermore, the idea itself is not simple or rigidly defined. It permits diverse urban forms in its realization. In order for us to have a better understanding of the potentials of the compact city, we need to accumulate knowledge based on both theory and practice.
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