Tuesday, November 01, 2011

The Population Surge is Stopping

Population surge difficult to halt and almost impossible to reverse was published yesterday in the Irish times. It is also availible in blog form here. The article makes some interesting and arguable claims about human environmental damage to the planet. These are based however on claims about human population that do not match the evidence or the UN's demographic predictions.

Today, just like every day for the last 50 years, around half a million babies will be born.

This is not true the figures from the UN are here. In detailed indicators look in births and in select country look in world.
Between 1960-1965 302136 babies were born each day. Between 1985 and 1990 375909 babies and between 2005 and 2001 367320 babies. The 500000 figure is not just wrong but drastically wrong.

The geometric nature of population growth makes it extraordinarily difficult to arrest, and almost impossible to reverse. The last population doubling took only 40 years. Even if global population growth rate drops to just one per cent, today’s seven billion would swell to an unimaginable 14 billion in 70 years.

The growth rate is being arrested. As I have said before in "We have reached Peak Baby" the number of children each woman has has been falling for decades.

"1968 women got 1.87 adult daughters. Ehrlich called it population bomb. Now women get 1.07 daughters, 92% of way to population balance done." Says Hans Rosling. In 43 years we have gone from 1.87 adult daughters to 1.07 a decline of .8 and we only need a decline of .07 more to reach long term balance of the numbers of women. Rural agrarian Bangladesh has reached stasis in adult female population levels for example.Look at the gapminder video here for yourself the number of children per women is declining

Though surprisingly accurate population estimates get better over time. For example the 2050 estimate has been recently honed in

U.N. Raises “Low” Population Projection for 2050
The "low-variant" scenario of population growth now foresees 117 million more people on the planet in 2050 than it did two years ago.
While the "median-variant" scenario, often seen as "most likely," remains almost the same as before - predicting a world with 9.2 billion people by mid-century
The high projection, however, foresees some 10.5 billion people - a 295 million person decrease from the previous high projection. The medium projection is 9.2 billion people,

It says something that an decline in the high estimate an over 2.5 times bigger than the increase in the low estimate is not the headline.

There are still countries that have very high birth rates per woman. Senegal for example had 7.5 babies per woman in 1968 4.8 babies and in 2010. But these countries are developing at a speed that is likely to see these birthrates drop rapidly. "Senegal has lower borrowing costs than Ireland." and a GDP growth rate of 4.2%. As these countries that still have a high birthrate develop their birthrate will drop rapidly the way ours and other developed countries did.

The article is in the Irish Times gives the wrong figure for the number of births per day and "unimaginable 14 billion" scare figure. The demographic evidence and historical trends indicate the population will not go to this level. Current UN estimates are for the high population prediction do not match this figure for 2081. There were never that many babies born per day and the birthrate has been falling so fast that we will not reach the 14 billion in 2081 figure.

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