The megacity of near-future Tokyo, from the movie Ghost in the Shell.

Tech Level: 10
Cyberpunk Sprawl
Tech Level: 12
Continent City
Tech Level: 14
World City
Tech Level: 16

By the year 2030, it is estimated that two-thirds of the world's population will live in an urban environment. This will in fact be the end product of a process that has been ongoing for more than the last half-century--the explosive growth of the size and scope of the world's cities.

Even though modern cities are not megastructures by the strict definition of the word, the need for ever-more careful planning, fully coordinated large-scale construction, and long-range integration of new technologies as these urban centers grow will slowly transform them from haphazard collections of commercial and residential zones into complex, unified structures on a grand scale.

This article assumes the cities on the surface of a life-bearing planet, mostly a future version of Earth. However, megacities can also be located in artificial environments, such as underground on the Moon or Mars, and on megastructures such as O'Neill colonies. Many of what is discussed for planet-bound cities can also be applied to these situations as well.

Tech Level: 10
The current twenty largest megacities. Source: National Geographic

A Megacity is currently defined as any urban center that has a population exceeding ten million inhabitants. This includes not only what's within the city's borders proper, but all its closely associated suburbs and urban development zones. These are often described as the city's 'greater' area in popular usage, such as the Greater New York Area or Greater Tokyo Metropolitan Area or similar. As of this writing, there are between 22 and 25 megacities worldwide, depending on the source, and this number is sure to grow substantially in the decades ahead.

As urban centers become ever larger, the challenge of the upkeep of their infrastructure as well as maintaining a decent standard of living for its many millions of inhabitants presents a number of technological and logistic hurdles. Prudent long-range planning and a recognition of projected growth would seem to be the major key to both, but in many of these megacities such efforts often fall short. As a result, megacities are often hodge-podges not only of different cultural and economic neighborhoods, but also of uneven zones of decay and urban renewal.

These zones are not always the same from Megacity to megacity. One Megacity may have a decaying downtown but a thriving rim of suburbs; Another may be seeing a large investment in their central commercial sections while the outlying townships are gripped by overpopulation and decay. Still another may invest most of its building budget in its ports or highway offramps, and let the rest rot.

Waste disposal is often a major issue in these modern megalopolises. The larger the city, the more sewers and sewage treatment plants and landfills are needed to handle the mountains of waste and garbage the city will produce everyday. Today, this is a serious issue with no easy answer; some megacities, especially in the developing world, are beginning to be choked by their own waste. As urban centers keep getting larger, new methods for dealing with this problem will have to be developed.

Also, even though it struck a merely "large" city, the Hurricane Katrina disaster in New Orleans in 2005 shows just how vulnerable modern metropolises can be to unexpected disasters. Megacities, being so much larger and with much higher populations, would be far more vulnerable to an unexpected disaster such as Katrina, especially if they have large percentages of poor inhabitants without the means to evacuate easily. Imagine if the Indian Ocean Tsunami of 2006 had hit a megacity area such as New York or Hong Kong with no warning.

Tech Level: 12
In the movie Akira, the new corporate mega-towers of Neo-Tokyo loom over the half-ruined Sprawl of the old city

The next step up from today's megacities are the urban 'Sprawls' so beloved of Cyberpunk fiction. The term was first coined by William Gibson in his seminal novel Neuromancer, but similar such super-megacities have been seen in a variety of Cyberpunk fiction, including films like Bladerunner and even comics such as Judge Dredd.

Sprawls assume that the trend toward ever larger megacities continues and even accelerates in the next few decades. Urban growth reaches a point where megacities relatively nearby to each other begin to merge, so that you could drive from one city center to the other without ever leaving a developed urban environment. For example, Los Angeles, San Francisco, and San Diego would all expand to the point where they become one single megalopolis sprawling for hundreds of miles along the southern California coast. On the east coast of the US, another megalopolis would stretch from Boston to Washington DC and subsume the existing megacities of New York and Philadelphia, resulting in a Sprawl that would be home to over a hundred million inhabitants.

One of the major features of the Cyberpunk version of such a super-city is the prominence of new urban technologies such as arcologies, mega-skyscrapers, and three-dimensional transportation systems such as elevated roadways or ubiquitous use of flying vehicles. But the Cyberpunk Sprawl also envisions the very unequal distribution of these new enabling technologies, where they are reserved only for the very rich and their allies. The majority of the Sprawl is inhabited by the disenfranchised and the poor, while those with means basically hide behind the gleaming walls of the corporate-showcase arcologies and gated communities.

However, it is also assumed that some necessities, such as food, power, clothing and the like, undergo a dramatic downturn in price and uptick in general availability, making life in the Sprawl at least tolerable for the average citizen. These benefits are generally attributed to new technologies creating consumer goods in ever greater quantity, driving the prices down just through sheer volume. In a cyberpunk city, for example, most high-performance computers are cheaper than lunch at a diner. There is some precedence for this trend, as all one has to do is look at how Wal-Mart and its contemporaries have made a number of consumer products dirt-cheap just through its broad distribution and ready availability. Whether this trend will continue into the future remains to be seen.

The production and distribution of food to the masses of a Sprawl also utilizes many new technologies in order to keep up with demand by the megacity's tens of millions of inhabitants. Fully-automated factory farms, undersea cultivation, industrial plankton vats, and the extreme high prevalence of artificial, pre-processed foods have all been mentioned in various sources. With mere contemporary technology and techniques, the Sprawl would by all rights should be stripping the surrounding farmland bare for hundreds of miles in all directions just in its sheer ravenous demand.

Neighborhoods in any city go through cycles where they decay, revitalize, decay, and revitalize again from decade to decade. Super cities such as a Sprawl will also feel this effect, but on a much larger scale. Entire townships may go through the cycle from decade to decade, affecting tens of millions of citizens. The arcologies that had once been gleaming corporate showcases may become slums twenty years later. Slum areas may be revitalized by corporate and government investment, and undergo renovation that soon turns it into a commercial or industrial center.

Waste management continues to be a major issue. Many cyberpunk sources that address the problem refer to major recycling businesses--run by greedy and corrupt corporations, of course--as well as freelance economies that sometimes spring up around old landfills. Downtrodden members of the Sprawl would mine the deep, compacted refuse piles like old time prospectors, looking for valuable materials that they could sell to the recycler centers. This is done on a limited scale today in certain cities, but one can imagine that in the massive landfills a Sprawl would generate that this could actually make some garbage "prospectors" rich.

Tech Level: 14

Technically, there is no limit to how large cities can grow, as long as basic needs of its population can be met and its infrastructure can be maintained. The next step up from a Cyberpunk Sprawl would be urban centers that stretch across entire continents, from one coast to another. There may still be large swaths of wilderness or farmland, but compared to the size of the city itself they at best could be considered parkland.

Cities on such a scale would need many new technologies to keep them viable. They would for example generate enormous amounts of waste and garbage, to the point that it could bury the remaining arable land and even surrounding oceans, dooming the city if not managed prudently. Recycling of every material capable of such would be a necessity, as would renewable and non-polluting sources of energy, such as solar, geothermal, and wind. A city of such a size would take every opportunity conserve its resources without generating potentially hazardous mountains of waste that could choke it and the surrounding ecosystem to death.

Feeding such a huge megalopolis would also be very problematic. Its possible only one such continent city could exist, and the rest of the planet's landmass could be converted into farmland to support it. For multiple continent cities, however, alternative means of food production would be necessary, many of which were already outlined above for Sprawls.

Continent-sized cities need not necessarily fill up an entire continent. They may have other configurations and geometries that would add up to a continent-sized urban area. For example, in the computer game Septerra Core, a city stretched entirely around the equator of a world-shell (a hollow artificial planet), making it the equivalent of a continent-city.

Tech Level: 16
The planet Coruscant, home to a world-city in the Star Wars universe. Image (c) Lucasfilm.

This is a city that has completely taken over the surface of a planet, covering over its entire landmass, and in some cases large swaths of its undersea regions and polar icecaps as well. The two best known examples of world-cities in science fiction are Trantor from Isaac Asimov's Foundation series and Coruscant from the Star Wars film series, both capitals of galaxy-wide empires. Another fantastically-advanced example can be found in Larry Niven's novel Ringworld in the form of the Puppeteer Homeworld. Asimov's Trantor held 45 billion inhabitants, Coruscant some 176 billion. The Puppeteer's Homeworld held an estimated one trillion alien citizens.

While there would be room for housing so many inhabitants in a world-city, depending on how much total volume the city structures occupy, the true limiting factor to the population for any such structure would be logistic and environmental concerns.

Food and fresh water would be one of the major necessities, and providing it on a daily basis for tens of billions of inhabitants can be quite a daunting challenge. Trantor had a fleet of thousands of starships whose sole purpose was to import daily foodstuffs to the massive world-city. Even so, Trantor still supplemented these with a thriving industry dedicated to vat-growing yeast and algae on a massive scale. Waste and water recycling had to be draconian in its efficiency, or even Trantor's open seas would become clogged by the mountains of human waste that could accumulate. How Coruscant or the Puppeteer Homeworld dealt with these problems is left vague, though the Puppeteers possessed both matter conversion and cheap teleportation technology, which could greatly facilitate recycling even for its massive population.

Dealing with environmental issues of a planet-sized city would be mind-boggling to say the least. Coruscant, for instance, does not have the open seas of Trantor, so one has to wonder how the oxygen-nitrogen atmosphere remains breathable without algae and other open plants to recycle the air. The planet's industry would have to engage in active atmospheric filtering and recycling on a massive scale just to avoid the billions of inhabitants from choking on their own exhaled carbon dioxide. Weather control may be used more for global circulation to prevent asphyxiation of entire regions than anything else.

Which brings us to a major new environmental issue all such world-cities will eventually have to deal with--heat pollution.

Billions of inhabitants and their attendant high-technology activities and industries create a lot of heat. As their numbers soar into the tens of billions and the hundreds of billions and beyond, this amount of heat rises substantially as well. This is NOT the same type of global warming problem we face today, which is caused by the accumulation of greenhouse gasses, though some of the same effects are present. Rather, this is a direct accumulation of heat energy itself through the activity of billions upon billions of inhabitants.

Trantor had open seas and intact polar ice regions to act as heat-sinks, and they built heat-radiator vanes at the poles reaching to the edge of space to dissipate some of the accumulated heat. The Puppeteers dealt with the problem by moving their world into interstellar space, away from any parent star, to let the excess heat bleed off into the void.

The general character and look of world-cities vary from source to source as well. Trantor's world-city was almost entirely domed or built underground, with weather-control technology in place to mitigate the worst of the storms that could still arise. Coruscant was a larger, open-air affair that covered the entire surface of the planet with many gleaming towers and skyscrapers, and was built many layers deep over thousands of years. The Puppeteer Homeworld was rife with arcologies and large tracts of parkland, saturated by teleporters called "stepping discs" that made the whole planet easily accessible from any one point. This combined with the Puppeteers' alien herd mentality helped to mitigate the crushing claustrophobia that could come with such a high population density.


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The Foundation Series by Isaac Asimov

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Article added 5/24/07