If our species had started with just two people at the time of the earliest agricultural practices some 10,000 years ago, and increased by 1 percent per year, today humanity would be a solid ball of flesh many thousand light years in diameter, and expanding with a radial velocity that, neglecting relativity, would be many times faster than the speed of light." - Gabor ZovanyiThat didn't seem possible - until I did a rough approximation. An increase of 1% per year, according to the rule of 72 (which may be accurate for such a small number), would mean a doubling every 72 years. Lets be conservative and translate 1% annual growth to the population doubling every 100 years [and thus avoid the nitpicking argument that two people can't increase by 1%].
10,000 years would allow for 100 doublings, which according to a QI comment... "You should end up with a figure of roughly 3.27 x 10^43. Which is quite a lot." It is, of course, another variant of the ancient puzzle of placing doubling grains of rice on a chessboard.
I often weary of every politician, businessman, sports coach, guidance counselor etc. mindlessly repeating a mantra that something has to get bigger to be better. Buildings have to taller, cars faster, bandwidth wider, budgets increased, growth is inevitable and necessary to progress.
There are limits to growth.
*One of the forums at QI led me to the source of the quote: "his quote comes from the book The No-Growth Imperative by Gabor Zovanyi. In which he cites (141, p198) this example as taken from a calculation done by P C Putman taken from The Economic History of World Population by Carlo M. Cipolla."