World population is expected to hit 7 billion on October 31st

One of the best books of 2010: Jonathan Franzen’s Freedom . I wasn’t alone. It earned rave reviews and reached a mass audience. Even Oprah even brought it to her book club. I only mention this because the protagonist is concerned with a challenging topic that doesn’t get enough attention: Population growth.



“One of the characters in the book has a bee in his bonnet about world overpopulation, and he points out, rightly, that pretty much every serious problem we have in the world is, if not caused by too many people, certainly aggravated by it,” Franzen said. “And he’s frustrated in the book because it’s become kind of a taboo thing, nobody will talk about it, it’s the elephant in the room.”

The room just got smaller and the book more timely. The United Nations announced yesterday the world’s population will reach an historic 7 billion people on Oct. 31, 2011. In 1804, the world population hit 1 billion and it took 123 years to add the next billion. However, it took less than a century for the next four billion. That means we went from 2 billion people in 1927 to 6 billion people in 1999. The U.N.’s Population Division also projected that the world will reach just over 10 billion by 2100.

How do we balance growth? How do we accomadate human lives with the planet’s limits?

According to Elizabeth Leahy Madsen at Grist , “the U.N.’s projections — presented in the 2010 revision of World Population Prospects — offer only a few scenarios and are based on potential changes in policies, services, and behaviors. They do not account for all the realities we see on the ground, where in some countries, women are not getting the family-planning services they want. The decisions and policies we make today will ultimately determine whether our numbers climb to anywhere from 8 billion to 11 billion by mid-century.”

U.N. population projections — will we follow the high, medium, or low path?

Where and why is this growth happening?

From Gris t: The U.N. projections show some striking changes in countries’ projected populations for 2050. Forty countries’ populations are projected to at least double in the next 40 years, including Afghanistan, Iraq, and Yemen. Nigeria’s population for 2050 is projected to jump by 150 percent, from 158 million to 390 million.

Many of these increases in projected population, especially those in sub-Saharan Africa, are due to persistently high fertility rates. The projections assume that the average number of children per woman will begin falling in such countries, but this is often a rosy assumption. For example, Nigeria’s fertility rate for 2010-2015 was previously projected to be 4.8 children per woman, but has now been revised to 5.4. This difference contributes to a much larger total population by 2050.

Still, the assumptions built into the projections for many high-fertility countries would require major increases in the use of family planning. Nigeria’s fertility rate, measured [PDF] at almost six children per woman in 2008, is projected to fall to slightly over three children by 2050. This is highly unlikely if current trends continue, because only 10 percent of married women in Nigeria use effective contraception, while 20 percent want to avoid pregnancy but aren’t using family-planning services. Until their health-care needs and rights are fulfilled, the demographic future the U.N. has projected for Africa’s largest nation seems too optimistic.

U.N. population projections — will we follow the high, medium, or low path? The projections may also be optimistic for countries at the opposite extreme, with very low fertility rates. Fertility rates in Japan, Korea, and Russia have declined significantly since the late 1980s. Their rates are now 1.4 children or less, which would lead to significant population decline. The U.N. projects that their rates will rise by at least 30 percent by 2050, but that may be based on faulty assumptions. Some researchers believe these very low fertility rates are linked to gender inequities and difficulty balancing work and family. If societies don’t become more woman-friendly and family-friendly, these fertility rates may not rise. As it turns out, a lack of opportunities for women may be the driving force behind both very high and very low fertility rates.

The surprising assumptions underlying some countries’ fertility rates reflect one of the key features of the population projections. In the past, the projections were constructed using a technique that, in the U.N. medium fertility projection, assumed all countries would move toward a universal fertility rate of 1.85 children per woman. High and low fertility projections only varied from the medium by 0.5 children per woman in either direction.

If anything, this growth indicates better policies for family planning - but as we know, we seem to be headed the other way.