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Population… • The population of the world has doubled since 1967. Even with an anticipated leveling in the later half of the century, the United Nations (UN) predicts 10 billion humans will inhabit Earth by 2100. UN projections also predict that 80 percent of the population will be living in cities – some with very large numbers. • In 2008, for the first time, over half of the human population lived in cities. This shift isthe result of a transformation that began 10 thousand years ago when hunter-gatherers began to abandon their nomadic lifestyle in favor of farming the land. Some claim that this agriculture supported the establishment of the first known cities in Mesopotamia. Towns and cities grew in number and size, spreading around the globe; however, until recent times most people lived a rural existence as farmers or fisherman.
EXPLOSION! • In the 18th and 19th Centuries, advances in agricultural technology and the Industrial Revolution shifted the population toward cities. In recent decades, heavy migration from rural areas and an exploding global population dramatically accelerated this trend, swelling developing-world cities across Asia, Africa, and South America. Ten of the world’s largest cities, the so-called megacities of over 10 million, are located in Asia. India alone has two of the biggest cities in the world, Mumbai and Delhi, both with populations of over 20 million. Cities of such numbers are considered metacities. In addition, India has 25 of the world’s top 100 fastest growing cities.
City Challenges…. • Developed and developing-world megacities face essentially different challenges. High-income industrial cities deal more with green agenda issues like greenhouse gas and recycling, while developing-world cities struggle with brown agenda issues - the immediate, health-related problems such as the lack of safe water, poor sanitation, and inadequate waste management. Water-borne diseases are major killers of slum dwellers, especially children. • Worldwide, an estimated one billion people live in slums, many of them located in developing- world megacities with already overtaxed infrastructures caused by overwhelming migration. Globalization has mostly benefited major cities and manufacturing centers, making them a lure for the rural poor. Many of the immigrants are agricultural workers displaced by technology and international trade. Massive slums and shantytowns, also called informal housing, surround major cities across South America, Africa, and Asia.
Without Solutions! • Many of the residents endure squalor, crime, and disease in hopes of a better economic future. Efforts to discourage rural migration to cities or to relocate slum dwellers have proven ineffective. Experts say a better strategy is to provide the slum dwellers with ways to improve their own conditions while governments are helping with infrastructure improvements and basic services such as clean water, improved sanitation, and protection from crime. These improvements will not happen overnight since developing-world megacities commonly lack the administrative and physical infrastructure to meet the needs of their escalating populations. Worst off are the squatters living in vast shantytowns without legal rights to any city services.
Climate Changes • A recent UN report found that climate change is increasing the flooding of coastal areas where many of the world’s megacities are located. This flooding could be caused by increased rainfall, severe weather events such as cyclones, or increases in sea level. New York City, Mumbai, Tokyo, Lagos, Dhaka, Rio de Janeiro, and Cairo would be threatened by projected sea level increases. In the past, the projections have been low, resulting in more damage than expected. The 16 million residents of Dhaka, Bangladesh live in a flood plain and could be engulfed by even modest sea level increase.
Environmental Disasters • While poorly planned and managed megacities are environmental disasters, urban planners and environmental groups view properly designed and constructed cities as green alternatives to urban (suburban) sprawl. Los Angeles could be considered an early example of a sprawling, car-dependent city that treads heavily on the environment. A New Urbanism movement promoting compacted living and a more sustainable urban environment is influencing urban planning across the developed world. While most notable in Europe, this movement as a concept competes with the United States, a car-based nation that has promoted cheap gas and the suburban ideal since the end of World War II.
Green Urbanism • New Urbanism, sometimes called Green Urbanism, draws on the compact city model where work, play, and shopping are all within easy reach for local residents. Walkable, mixed-use neighborhoods and efficient public transportation are emphasized. Newly-emerging smart city strategies use innovative techniques, with the goals of a greener environment and a decreased carbon footprint. These efficient technologies include computer-networked grids of sensors placed throughout the city to monitor and manage energy use, traffic, and pollution. • Developed-world residents in high density cities such as New York may have a more modest carbon footprint because they live in smaller spaces than their suburban counterparts. Residents choose to walk or use more efficient public transportation and use less energy for heating and cooling; however, higher density cities may improve the global environment at the expense of worsened local conditions. This phenomenon has been named the paradox of intensification since while per capita car use is reduced, the overall concentration of car use rises. To address this paradox, compact cities are being designed, public transportation enhanced, and smart grid technologies implemented to improve the flow of traffic and minimize pollution-causing traffic jams.
High-Density Cities • The best environmental argument for compact, high-density cities is the need to preserve critical biodiversity. According to experts, this can only happen if large, continued greenspaces with intact ecosystems are preserved. The Canadian government is alarmed about the country’s inability to stem an increasing loss of species and claim that urban sprawl and industrial development are major contributors. Ironically, Canada has far more intact greenspace than most developed countries. • If the global population is expected to increase by 3 billion people by mid-century, perhaps we had better design ways to take up less space. Some environmentalists are embracing the high-density, high-rise cities that once horrified them.
SKYSCRAPERS! • Is there such a thing as too big? The law of accelerated productivity states that if the size of a city doubles, the result will be 15 percent more output per inhabitant and increased productivity. In addition, the economies of scale mean that it is more efficient (less cost per person) to provide infrastructure (roads, sewers, power, etc.) for city dwellers. These conditions favor growth. At a certain point, however, an over-utilized infrastructure causes dis-economies of scale. Productivity and quality of life suffer and the city declines if it cannot respond to demand. These “dis-economies” are thought to be contributors to the current growth trends that favor less-than-mega cities. Emerging economies with sufficient resources, like China and Brazil, are investing heavily in infrastructure improvements for their megacities.
Technology • Urban migration is a major factor in the welcomed decline of the world population growth rate. Since large families are not the asset they once were in an agricultural society, women living in urban environments are exhibiting a consistent pattern of having fewer children. • Technology is giving the world new capabilities for better understanding and forecasting the weather and seismic events that are especially threatening to megacities. A host of new technologies, including Information and Communication Technology (ICT), will be beneficial and economical tools for managing megacities. They show outstanding promise for improving the lives and economic opportunities for residents. A UN program, for example, is supplying broadband to the favellas of Rio de Janeiro to foster entrepreneurship.
Urbanization! • One thing upon which experts agree is that the trend of urbanization displays no signs of slowing. The optimum size and design of our cities remain to be determined, but some challenges are clear. How might we address the massive structural problems caused by unplanned, explosive growth in megacities without adequate resources? How might we prepare for mass dislocations of the urban poor threatened by rising sea levels? What are the best strategies for improving the lives of one billion and counting slum dwellers? If high-density living is essential for environmental sustainability, how might we make cities more livable?
