The @PopulationMedia Center is questioning some conclusions of the population analyst Joseph Chamie in my post on Japan’s great diaper shift. (The aging country’s adult diaper demand is almost outpacing the market for baby diapers.)

Here’s a note circulated by Joseph Bish of the Center:

I thought today might be an easy one, but was immediately confronted by a challenging post by Andy Revkin at his Dot Earth Blog. In it, Andy reflects on his experience in Japan this fall, and brings up some data indicating the population of Tokyo may peak by 2020 before moving into the notorious "diaper-dynamic" of Japan (wherein adult diapers are close to selling at the same number as infant diapers in the country). This compels him to reach out to Joe Chamie, who reinforces the notions set forth in a 2010 essay Chamie wrote titled "Global Population of 10 Billion by 2100? - Not So Fast." In sum, Chamie believes that:

1. fertility will come down from high levels more quickly than expected;
2. fertility will remain below replacement level in low fertility nations;
3. world population unlikely to reach 10 billion by century’s end.

There are several areas worth remarking on here. First, Chamie’s initial assertion is at least partially called into doubt by the recent upwardly revised UN Population Projections. For example, here is John Wilmoth, Director of the Population Division in the UN’s Department of Economic and Social Affairs. "In some cases, the actual level of fertility appears to have risen in recent years; in other cases, the previous estimate was too low."For the full UN press release click here (PDF). Also, please note the UN is projecting 10.85 billion by 2100 for the medium variant, not 10 billion as Chamie indicates at the end of theDot Earth post.

Next, Andy relays Chamie’s thoughts that family sizes in high fertility countries of Africa and Asia will continue to decline because of "increasing urbanization, smaller and costly housing, expanding higher education and career opportunities for women, high financial costs and time pressures for childrearing and changing attitudes and life styles." This is a very different “picture” than many of us are familiar with. (In that light, I have re-ran an essay by the President of Worldwatch Institute, Bob Engelman, which was published in Yale360 this summer.

Overall, its not clear to me if the Dot Earth blog goes into the naughty or nice category. But, at any rate, it is good food for thought. And, on that note — Merry Christmas. May we continue towards the ideal of Peace on Earth.