In the time it takes you to read this sentence – five seconds or so – the world's human population will have grown by another 10 to 15 people.
About 20 babies will have been born, but between five and 10 people will also have died, pushing the global total to somewhere around the 7 054 047 031 mark – give or take a million or so.
Biologically speaking, Homo sapiens is one of the most successful species to have populated Earth since the first multicellular life forms emerged about 1 billion years ago.
But on World Population Day on Wednesday, environmentalists warn that there is little cause for celebration.
"We need to remember that it's our environmental impact, our total burden of resource use and waste output that threatens our survival," says Wessa chief operations officer Mike Ward.
In biological terms, the human population has grown extremely quickly and that growth accelerated until the 1960s, when various factors – notably the Pill – started reducing the rate of increase. But the numbers are still alarming: of the estimated 110 billion modern people who have ever lived, more than 6 percent are alive today. It's not possible to be perfectly accurate, but scientists have calculated how the human population has grown: from 1 million in about 10 000BC, to 500 million somewhere in the 16th or early 17th centuries, to 1 billion in the early decades of the 19th century.
By 1930 it was 2 billion and the third billion was reached in 1960, followed by the 4th, 5th and 6th billions in 1975, 1989 and 1999. The UN calculated that the 7-billionth person was born on October 31.
Future projections are for the growth rate to continue to slow, with the global population reaching 8 billion in 2025 and – perhaps – topping out at somewhere between 9.8 billion and 10.5 billion (depending on what source you look at) in the middle half of this century.
Ward says human environmental impact is the product of three factors: overall population; individual consumption; and technology, which determines how many resources are used and how much waste is produced.
The World Food Programme pointed put last year that no one knew who the 7-billionth person was – "but we do know there's a one in seven chance that person will be born hungry. Nearly 1 billion people in the world go to bed hungry each night".
john.yeld@inl.co.za
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