It is possible to fit 6 billion people into the Isle of Wright with room to spare. In fact, you could fit 27 billion people into a cube one mile by one mile by one mile.

Only catch is, each person would have 12 cubic feet, or six feet by two feet by one foot. Now imagine that you're at the bottom of the cube.

What is overlooked time and time again in the "you can fit x people into ____" argument is that just because you can fit a population into an area doesn't mean that area can support it. The most common example is Texas, at least in America. But what about arable land?
"If you divided the world's 6 billion humans into Texas's 261,914 square miles, each person could claim .028 acres of land. It is obvious, however, that the land in Texas, (or even the land in North America for that matter), would not be able to sustain these people. Resource experts say a minimum of 0.17 acres of arable land is needed to sustain a person on a largely vegetarian diet without the intense use of fertilizers and pest controls.

An estimated 253 million people currently live in countries with scarce arable land--which have on average no more than 0.17 acres available per person -- and this population is expected to at least triple by 2025 if current trends continue. Only 11 percent of the Earth consists of arable land, and that area is rapidly diminishing due to erosion, salinization and a decline in the practice of fallowing land."

http://www.zpg.org/Reports_Publications/Reports/report83.html
As for space, let's say people will be transplanted to Mars by 2030. The world population will be 8.1 billion by then (http://www.census.gov/ipc/www/worldpop.html). In order to maintain current population levels, we would have to devise methods to transplant 2 billion people within thirty years. At a round trip of two years to get to Mars at the optimal revolution of the planets around the sun, with 50,000 people making the trip each time, you would need to make 40,000 trips before you could transplant 2 billion people, over the course of 80,000 years, at which point you might see H.G. Wells and his time machine where London once was.

What's my point? Look for answers close to home. Keeping your head in the clouds can be fun, but not always productive. Rather than trying to find solutions to the effects of overpopulation, one should try to find solutions to the causes of overpopulation.


For those interested, let's say we started sending people now and wanted to make sure we were at 6 billion people in 2030; the number of trips that could be made is 15, at 133 million people per trip. The maximum number of people to send at today's capability per ship is about ten. That's 13 million ships being sent every two years, plus enough food and water to feed people for the ten to twenty years it would take to allow for food to be grown on Mars. Put the cost of sending each ship at 20 billion dollars (http://www.miami.com/mld/miami/news/world/3607347.htm), not counting the cost of constructing habitats on Mars, and not counting the cost of constantly sending supplies (and even then 20 billion dollars is very modest). That's 260,000,000,000,000,000 dollars (two-hundred sixty quadrillion dollars) every two years, at a total cost of 3,900,000,000,000,000,000 (three-quintillion nine-hundred quadrillion dollars) over the course of thirty years. If every person in the United States (287 million as of this year) were to pay an equal amount towards this, the cost over thirty years would be 13 and a half billion dollars, each.