The age of man

By Economist.com

The sum of human experience is growing as the world gets older and lives longer

THE world's population surpassed 7 billion in 2011, only 13 years after marking the previous billion-person milestone. In that short time, the aggregate age of everyone alive rose by 46 billion to over 220 billion years lived. In 2011, the average person was just under 32, four years older than in 1950, when a mere 2.5 billion souls lived on Earth. Since then, thanks to economic growth and improvements in living standards, average life expectancy at birth has leaped by 20 years, to 68. The UN's population projections show a continuation of this trend. By the end of this century the average person will be a little over 42 and newborns can expect to live to 81. The world's population will have stabilised at just over 10 billion and those people will have accumulated 430 billion years of human experience between them. Given the challenges the planet may be facing by then, it is to be hoped such experience brings them wisdom as well.