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	December 30, 2003

RUNNING OUT OF ROOM, RUNNING OUT OF TIME When I was researching the article One Billion Americans?, I got thinking about the implications of the wildly conservative Census Bureau projections of US population, and the embarrassing drastic upward revisions that have been made to them, for global population projections. What made the US projections so wrong (US population peaking at 295 million was predicted as recently as fifteen years ago) was the compound error of underestimating the extent of immigration and overestimating the rate at which immigrants adjust their family size to the average of their new country, or the global average. It's an understandable error -- there's lots of evidence that population growth rates in the developing world are falling quickly. But that's not because third world countries are evolving to two-child-or-less families as infant mortality drops. Rather, it's because those countries are simply unable to sustain more children, so parents are reluctantly, temporarily reducing family size as a result. Give them the option to emigrate to a developed country, and cultural preference, religious dictates, and improved health care will jump their family size (and life expectancy) back up again. And as inevitable ecological and humanitarian catastrophes arise in the 21st century in dozens of third world countries, compounded by the scourges of new diseases, horrendous shortages of clean water, and desertification and crop flooding due to global warming, the pressure to increase immigration quotas by orders of magnitude will be fierce. Back in 1990 when the pundits were predicting US population would peak at 295 million (it passed that level last year and is now expected to peak at between 550 million and 1.2 billion, if it peaks at all), they were saying global population would peak at around 9-11 billion in 2100. But for that to happen with a US population of, say, 900 million instead of 300 million, would mean average third world family size would be much smaller than average US family size. The UN projections, for example, assume annual average growth rate for Africa, Asia and Latin America of 0.5% in the latter half of this century, compared to a current growth rate in those areas (even including China with its already-low birth rate) of 2.1%, and compared to a current US growth rate of 0.9%, which is trending back up to a projected 1.3% rate for most of the current century, thanks to immigration. So the 9-11 billion global peak population just doesn't add up. While it doesn't make sense to get Malthusian and project population will grow indefinitely at current rates (1.3%, i.e. a doubling every 50 years to 24 billion by 2100), it's equally illogical and irresponsible to suggest that the whole world will start immediately radically reducing its fertility rate to achieve in just two generations the low fertility rate that Europe took one hundred generations to reach. If you assume that the levels of immigration now projected by the US Census Bureau will prevail throughout the developed world, that first- and second-generation citizens of developed countries will continue to have considerably larger-than-replacement level families in their new adopted countries, that the prevailing pro-fertility population dogmas of organized world religions will not suddenly be changed, that population pressure in the third world will be eased somewhat by immigration and that modest drops in family size in those countries will be largely offset by longer life expectancy, as has been observably the case in almost every third world country except China, then instead of the 9-11 billion peak the UN is currently talking about, you end up with population soaring past 14 billion in 2100, with no end in sight (left chart above). The curved red line shows the carrying capacity of Earth, assuming a modest annual increase in productivity from the current 30 billion acres (productive-capacity adjusted), assuming average footprint per capita continues to increase by a modest 1% per year, and assuming no land on the planet is reserved for wilderness or natural space for the rest of Earth's creatures. It shows in 2000 that the world could sustain 5 billion humans at the then-prevailing level of consumption. That's a billion humans less than actually inhabited the planet then, possible only by depriving much of the world of a subsistence level of resources, and by taking more from the Earth (in non-renewable resources) than we replaced, essentially stealing the excess from future generations. At the expected global level of per-capita consumption in 2100 (still well below today's North American consumption levels), carrying capacity drops to 2 billion humans. That number is substantiated by a recent Cornell study that says the choice in 2100 is between 2 billion people living a comfortable but not lavish life (achieved by a drastic population reduction) or 12 billion "struggling in misery". And if you want to allow 50% of the planet's surface for other life forms, you need to achieve double that reduction (green line), to one billion people, the level both Jim Merkel and Bill McKibben think we should strive for. That's only achievable, short of coercion, by an average one child family worldwide for the next century. The right chart shows that the increasing average footprint, driven both by North American excess and the surging resource use of China's billion plus people, will drive the aggregate human footprint up even more sharply than aggregate population, from 37 billion acres today (20% more than Earth's carrying capacity) to 210 billion acres in 2100 (six times Earth's carrying capacity). Now remember, these assumptions are much closer to the wildly optimistic assumptions of population levelling that the UN and other global agencies optimistically hope for, than to the Malthusian no-change projections that would see nearly double these numbers. Nevertheless, train wreck ahead. We simply have no choice. We must immediately and aggressively reduce our family sizes worldwide, and we must immediately and aggressively reduce per-capita resource consumption, waste and footprint. That means we must confront religions that don't actively encourage birth control and small families, and show those religions to be socially irresponsible. That means, too, we need to introduce ecological taxation measures to make excessive resource consumption and waste prohibitively expensive, and reward those who tread lightly on the Earth. 11:26:29 AM  trackback []  comment []

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