3% of the Earth's surface is urbanized.
Coastal environments have 65% of the world's urban population.
7% of urban dwellers live in the world's largest mega-cities.
Tokyo is the world's largest urbanized area, at 30,000 square kilometers.
These are just a handful of the findings of GRUMP -- the Global Urban Rural Mapping Project -- run out of Columbia University's Earth Institute. A four year project, GRUMP is one of the first efforts to combine satellite mapping data with population census information. This combination has led to new insights into the distribution of human population across ecosystems, as well as into changes in the pattern of rural/urban development.
GRUMP has an enormous amount of data for those of us interested in the growth of urban communities:
GRUMP Human Settlements is a global database of cities and towns of 1,000 persons or more, each represented as a point, and includes information on population sizes, longitude and latitude coordinates, and data sources. Populations were estimated for 1990, 1995 and 2000. The GRUMP Urban ExtentMask is the first systematic global-scale attempt to portray the boundaries of urban areas with defined populations of 5,000 and larger. The GRUMP Population Grid represents the distribution of human population across the globe, accounting for urban population concentration more precisely than previous efforts.
Best of all, the GRUMP data are available for free use. A web interface allows access to much of the information for casual browsing (which can easily eat up an afternoon), and more serious users can also download the data for each country in standard GIS formats. This is a tremendous contribution to the study of urbanization, and Columbia should be commended for making the data freely available.
I sometimes wonder is there is really a honest reason why we're not spread out more over the whole planet. Except for politics (power and control) there is afaik no reason why we should all be living in such small crowed spaces. Still, most politicians tends to be centralists and concentrationalists no mater if they are left, right of center.
The rules of politics favor (are bias to) centralization and concentration. It's considered easier to negotiate with one company which employs 5,000 workers, then to negotiate with 5,000 self employed citizens who all have 0-2 workers employed. It's easier to make rules that favour big companies then the make rules which favour many smaller ones. History shows that out of anarchy comes democracy which will, given enough time, always turn into a totalitarian dictatorship, the ultimate in concentration and centralisation.
Our effects on our environment is greatly amplified by our concentration and monoculture, more diversity and a more even distribution would most likely dilute our influence to such a extend that it would have only a mild effect and maybe no effect at all on our environment.
Actually, Gideon, dense cities tend to have a smaller overall environmental footprint than sprawl. This is in part due to the reduced need for driving (both personal vehicles and shipping food, goods, etc.), and in part due to efficiencies inherent to multi-unit structures (vs. single-family structures). Also, people tend to like to be around other people -- not everyone, of course, but many of us.
For an even more radical study of density as an ecological savior, check out the hypothetical arcologies of Paolo Solieri:
These are really radical ideas that turn people's instincts awry at first glance, and they might actually be totally insane, but his one active experiment, Arcosanti, is trudging along in Arizona with a fraction of the residents it might one day have, but still with a reassuringly enticing, sustainable vision, producing almost all its own food and water (in the desert no less) and remaining a very nice place to spend time.
ItŽs an amazing project indeed.
Its a common misconception that dense cities are more effiecent in enrgy use. The fact is thats soo wrong its downright criminal.
A city dweler will think gee I dont need as much energy because I dont drive as much and im not heating my place as much as so and so...
But... how much energy did your building take to build? How far away from your city did the food your eating have to come from? Just where on earth is your garbage going? Do you know its common for a large city to have a powerplant just to provide the power to pump its own sewage? Anouther to power the waterworks. Anouther powers any eltrical mass transit systems.. Do you know how much energy it took to pump the water in your building up to your floor? Do you know how many busses are being run in your city and how much fuel each bus consumes each year AND how much energy it took to both make it and maintain each one of them? Do you know how much enrgy leaches out of powerlines in dense areas because buildings are right next to them and interacting with thier magnetic fields? Do you know how many cars your police force uses and how much gas that takes? Do you know how much energy and fuel and materials it takes to maintain your streets, rail lines, parks, public areas and so on? Do you know how many street lights your city has? Do you know how much material it took to build your city and how much energy that took? Do you know how much energy an elevator uses? Look out the window at night and count the number of lights on... Do you know how much energy all the tv and radio stations in your city consume not to mention all the repeater stations they need. How fuel efficient is the average bus in your city? Grabage truck? How much energy does it take to make maintain and run a subway? How much energy did it take to make each car in a subway train? How much energy is used up to deal with the heat island effect dense populations produce? Do you even know where your air conditioner is much elss how old it is and how much energy it uses? Look out a window and try to add up how much everything you see cost to make... amazing isnt it? Just who the heck spent the money to make all that junk anyway and what the heck is much of it doing?