Goldfarb mentions Andrew Revkin’s decision not to publish “private” — though publicly available — emails which cast the purveyors of climate change in a bad light. Just in case you were inclined to give Revkin the benefit of the doubt, here’s another small data-point on him. Revkin’s blog is called Dot.Earth. Here’s his explanation of it:
By 2050 or so, the world population is expected to reach nine billion, essentially adding two Chinas to the number of people alive today. Those billions will be seeking food, water and other resources on a planet where, scientists say, humans are already shaping climate and the web of life. In Dot Earth, reporter Andrew C. Revkin examines efforts to balance human affairs with the planet’s limits. Conceived in part with support from a John Simon Guggenheim Fellowship, Dot Earth tracks relevant news from suburbia to Siberia. The blog is an interactive exploration of trends and ideas with readers and experts.
How does Revkin know that the world’s population will peak at 9 billion? That figure comes from the United Nations Population Division which does really good, serious work on demography. Revkin is using their annual population survey, the most recent edition of which is from 2008. In it, the U.N. projects population forward based on a number of factors, particularly changing mortality and fertility rates. They use a range of assumptions and give multiple projections based on different variables. For the 2008 edition, for instance, they give three variant projections for world population in 2050: * 7.959 billion (low variant) * 9.150 billion (median variant) * 10.461 billion (high variant) * 11.030 billion (constant–that is, if all current conditions remain unchanged) But here’s the important part: The subject which has dominated most demography discussions for the last several years isn’t population growth, but population decline. Fertility rates are falling all around the world. Only one or two countries have positive fertility-rate growth. Fertility rates have fallen below replacement levels in almost all industrialized nations but the rate of decline is actually fastest in developing nations. The noteworthy part of the U.N.’s population report isn’t that peak number in 2050 — it’s that after 2050, the U.N. sees world population shrinking. By 2048, the U.N. projects that 76 percent of the world will have a fertility rate below replacement level (that’s 2.1 children born per woman). Only 22 percent of the world will have a fertility rate as high as 3.0. All of which means that around 2050, we’ll be hitting the high-watermark for world population. At that moment, the demographic momentum built up since the 1950s will have petered out and — because the average age will have increased markedly — people who haven’t replaced themselves will begin dying off in large numbers. Thus, when the U.N. did a long-range population study in 2003, they projected that after peaking at 9.2 billion, the world would spend the next century shedding bodies, drifting back down to 8.3 billion by 2175. There are too many caveats to list here — demography is barely science, let alone destiny. But do understand that the discussion in demography circles isn’t “How do we cope with two extra China’s?” Rather, it’s “How do we manage one of those extra China’s disappearing?” And that’s because throughout history, only bad things have happened when population declined. As Mark Steyn puts it, “There is no precedent in human history for economic growth on declining human capital.”
