How falling fertility rates are turning Britain into the old country

Last updated at 13:20 21 January 2008

Britain is getting older faster, according to scientists.

By the middle of the century, the average Briton will be 48.4 years old, against 39.1 years old now.

But by 2100, the rate of increase will have slowed, with the average age rising to 53.5 years.

Professor Wolfgang Lutz and colleagues at the International Institute for Applied Systems Analysis at Laxenburg, Austria, studied population forecasts and fertility rates in 13 major regions of the planet.

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Elderly woman

They found that by the middle of the century there is an 82 per cent chance that a third of the population in Britain will be over 60 thanks to people living longer coupled with falling fertility rates, compared with 98 per cent in Japan/Oceania and close to zero per cent for sub-Saharan Africa.

Professor Lutz, whose findings are published online by Nature, said the future paths of population ageing result from specific combinations of declining fertility and increasing life expectancies in different parts of the world.

The "speed of ageing is likely to increase over the coming decades and to decelerate in most regions by mid century", he added.

The study found the overall average of the world's population will increase from 26.6 years in 2000 to 31.1 in 2050 and then to just 32.9 in 2100, slightly less than what it was in China in 2005, owing to large differences in the regional patterns of ageing.

The researchers say the probability that world population growth will end in this century is 88 per cent, somewhat higher than previously believed. After mid century, lower rates of population growth are likely to coincide with slower rates of ageing.

Professor Lutz said: "Population ageing has many dimensions that will affect individuals and societies alike.

"In addition to changes in its level, the speed of ageing matters because, generally, the difficulties of adaptation to demographic change increase with the speed of change.

"In this respect, the world as a whole and the low fertility countries in particular face the challenge of an accelerating speed of ageing over the coming decades with the prospect of a slower speed of ageing at a higher level towards the second half of the century."