Our planet is home for 7.6 billion as of December 31st, 2017. I vividly remember Monday October 31, 2011 which saw the birth of the 7 billionth person somewhere in the world. Who this person is will remain a mystery (the date is an estimate), but we can be certain of the growing demands that humans increasingly make from our planet. Some people say that the rate of growth is decreasing: this is like slightly lifting your foot off the gas pedal (en-gb: accelerator), but continuing to accelerate. As, within six years we added 600 million more human life.
Time magazine says this about the numbers: “Demographers say it took until 1804 for the world to reach its first billion people, and a century more until it hit 2 billion in 1927. The twentieth century, though, saw things begin to cascade: 3 billion in 1959; 4 billion in 1974; 5 billion in 1987; 6 billion in 1998.
The U.N. estimates the world’s population will reach 8 billion by 2025, 10 billion by 2083 and by the end of this century it would be 11.6 billion. But the numbers could vary widely, depending on everything from life expectancy to access to birth control to infant mortality rates.”
At 10 months human pregnancy is not a easy event. However, I’m very sympathetic towards Asian elephants, whose gestation periods are 645 days, right up there with whales at 500-600 days. And I’m envious of hamsters and mice who incubate their little ones for around two to three weeks. Cats and dogs are pregnant for about seven weeks, twice that of rabbits. It’s clear that gestation periods are roughly linked to body size. Humans have evolved big brains for thinking and relatively narrow pelvises for running, and this makes human births much more difficult for mother and passenger than for most other animals.