Planet earth weighs six billion trillion* (6 times 10 to the twenty-first power) tons. If you wrote it out it would be 6 then twenty-one zeroes followed by the the word "tons." Dividing that by the present world population (6 billion plus) the result is a trillion (one followed by twelve zeroes) tons of earth resources for every man, woman and child. Even if the population increased a thousand-fold there would still be a billion tons per individual. (cf. Handbook on Population, p.43)
*Also called a "sextillion." See: University of Washington News Release
On Oct. 12, 1999 (the day the U.N. welcomed the 6 billionth child) the counter showed 6,018,000,000.
see: How much does the Planet Earth weigh?
Overpopulation: Asking the Right Question