Planet Korea

In 1970, per capita income in South Korea was a mere $248 and the birth rate was an average of 4.5 children per woman.

Today South Korea has a per capita income of around $17,000 and the latest data from South Korean health surveys shows that South Korea may now have the lowest birth rate in the world, with a TFR of just 1.2.

It's worth noting that Korea was once one of the countries written off as unsalvageable and a place where mass starvation was likely. In 1948, William Vogt made such pronouncements for a host of countries around the world (including Japan!) and his "lifeboat" and triage rhetoric was later picked up by Paul Ehrlich, Garrett Hardin and Bill Paddock -- and is still being used by some today.

While the world is far from out of the woods as far as population growth is concerned, the demographic history of Korea is a powerful beacon of hope for the rest of the world.

South Korea's fertility rate in 1970 was significantly higher than that of the developing world today (with or without China) and almost as high as that of Africa's today. The United Nation's Long-Range World Population Projection suggests that world population growth is mostly likely to continue for at least another 150 years, with world population expected to rise from 6.2 billion (today) to around 10 billion in 2150.

Continued human population growth, coupled with rising resource consumption in many parts of the world, continues to a very, very serious environmental issue. That said, the demographic history of Korea offers some hope. If the world's total fertility rate were to fall to 1.7 (higher than the current average fertility rate of the developed word), and if it stayed there for a long time, world population in 2075 would be about what it is now, and world population would actually fall to about 3.2 billion by 2150 or so.

If world fertility rates dropped to Korea's currently low rate of 1.2, however, and if it stayed there, world population would begin to fall rapidly after 2050. In the unlikely scenario that world fertility rates fell to Korean rates and stayed there for 150 years, world population would fall to significantly less than 2 billion people -- or about the population of the world in 1900.

In fact, birth rates are expected to continue to fall in the developing world.

That said, there is little reason to think world fertility will drop much below replacement levels, and stay there for decade after decade, unless that demographic scenario proves very beneficial to humans. In fact such a scenario may prove beneficial -- small families and rising personal wealth seem to go hand in hand the world over.