“As a species we have lived in wild nature for hundreds of thousands of years, and now suddenly most of us live in cities—the ultimate escape from nature,” says Kareiva. “If we do not learn to build, expand and design our cities with a respect for nature, we will have no nature left anywhere.”

Indeed, biocide is occurring at an alarming rate. Experts project that at least half of the world’s current animal species will be completely gone by the end of the century. Wild plant-life is also disappearing. Most biologists say that we are in the midst of an anthropogenic mass extinction that is at least partially caused by human encroachment on more and more areas of the planet. Numerous scientific studies confirm that this phenomenon needs to be addressed quickly.

this site :
http://www.worldchanging.com/
deals with many of these issues
cities will probably get denser with more allotments eco friendly designs etc.

Don't believe it. It's a Left wing conspiracy to make us communistic or socialistic. It's a hoax. Just close your eyes and relaaaax. And sleep; and deeper down... feels good to just sleeeeeeeep. And stay..... and forget about everything for now... just sleeeeeep. That's right, just sleeeeep.

zzzzzzzz.......

Turning the planet into a city would make as much sense as someone on thin ice proving they were tough by using a pogo stick.
If we started, the relics would be a great item on the 'Alien tourist circuit', and for alien archaeologists and documentary makers when they were explaining how it is possible to totally screw a planet. With a special disclaimer- 'Warning! Do not try this on your home planet.'
Humanity may not be able to explain directly, but there'll always be the DVD's that are likely to outlast the species.