Monday, April 18, 2005

All 10 million Europeans: demographic collapse.

All 10 million Europeans: demographic collapse.


The last two generations grew up with the idea of the "population explosion". For a century the world has lived with constant upward revision of population forecasts: the only question was if the growth would be fast, or very fast. And the last generation faced the question: how many billions can this planet support? So it is a culture shock, when new projections of global population include scenarios of dramatic population decline - without any meteorite impacts, new epidemics, or famines. Or when a UN report suggests that Europe needs 700 million immigrants to maintain its age structure... Is the future population nightmare not rural Bangladesh, but rural Estonia? Updated March 2005.

The myth of population growth was strong until recently. A few years ago, the website of the Latvian centre for demography research included this image of the population boom, a 1997 painting by A. Bauskenieks called Demographic Explosion.

Fear of growing population was a cultural norm in the west until the 1990's, but the popular images of an inevitably crowded future have largely disappeared. Studies of future population, such as the IIASA World Population Program, familiarised scenarios of global population decline. Their 1996 "low-fertility high-mortality scenario" gave a projected world population in 2100, of just 3937 millions - one-third less than at present. The latest (2004) projections by the UN ESA Population Division include a scenario with just 2300 million in the year 2300. Of course there are uncertainties in population forecasts. In the World Population Prospects 2004 Revision, there is a difference of 4 billion between the low-fertility scenario and the constant-fertility scenario. In the ESA scenarios, there is a gap of no less than 34 billion people, between the lowest and the highest scenarios for 2300. The further into the future, the greater the uncertainties and margins - and demographers continue to warn of the huge population growth in the next 50 years: see World Population: Major Trends

However, there is a reason to believe that long-term decline is the realistic scenario. You may remember (from school geography) the four phases of the demographic transition. For most of history, birth rates and death rates were high, at around 40 per 1000. Global population grew, but slowly and erratically: the first phase. In the last three centuries, beginning in Europe, death rates fell sharply. At first, birth rates remained high, and population grew: the second phase. With increasing welfare, birth rates also began to fall, and population growth slowed down: the third phase. Finally, in the usual theory, birth and death rates would stabilise at around 10 per 1000. The process took about 250 to 300 years in Europe, but some regions in Africa and Asia entered the second phase only a generation ago.

But is this the end of the story? What happens if birth rates fall permanently below death rates? It seems that eastern European countries entered a fifth phase of the demographic transition - and there is no evidence that this will ever be reversed. This declining phase is now included in some versions of demographic transition theory. For the EU countries, the Eurostat study projected a fertility rate stable at 1,95. The fertility rate is, approximately, the number of children per woman: a rate of 2.1 is necessary for a stable population. An EU fertility rate of 1.95 is permanently under replacement level - and that is the high-fertility scenario.

Most countries have not entered a fifth phase yet. However the Eurostat projections show a pattern, where rich countries, one after the other, go into population decline. And low fertility is no longer specifically European, and no longer limited to rich industrial countries. According to World Population Prospects: The 2004 Revision, 43 developed and 23 developing countries have below-replacement fertility rates, and they contains 44% of the world's population. Sub-replacement fertility now affects countries such as Armenia, Cyprus, Georgia, Kazakhstan, Singapore, Sri Lanka and Thailand.

It is no longer possible to say simply, that the end of the demographic transition is a stable population. Perhaps a shrinking population is "normal" - as growth was once considered to be "normal". Perhaps a shrinking population is characteristic of any planets with an advanced technology. If so, then Latvia and Estonia have also answered a theoretical question of SETI (Search for Extra-Terrestrial Intelligence). The famous question, used by those who do not believe in extra-terrestrials: if there are billions of advanced civilisations, why are they not here to visit us? Look at the table of Latvian population, project it 10, 000 years into the future, and you have an answer: there are not enough aliens to build a spacecraft. All those huge galactic federations in science-fiction films, with billions of billions of alien inhabitants, may simply reflect mistaken demographic theory.

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