Friday, January 25, 2013

World Population Growth Slowing, and Yet We Still Worry

Jeff Wise:
The world’s seemingly relentless march toward overpopulation achieved a notable milestone in 2012: Somewhere on the planet, according to U.S. Census Bureau estimates, the 7 billionth living person came into existence. Lucky No. 7,000,000,000 probably celebrated his or her birthday sometime in March. . . .

A somewhat more arcane milestone, meanwhile, generated no media coverage at all: It took humankind 13 years to add its 7 billionth. That’s longer than the 12 years it took to add the 6 billionth—the first time in human history that interval had grown. (The 2 billionth, 3 billionth, 4 billionth, and 5 billionth took 123, 33, 14, and 13 years, respectively.) In other words, the rate of global population growth has slowed. And it’s expected to keep slowing. Indeed, according to experts’ best estimates, the total population of Earth will stop growing within the lifespan of people alive today.

And then it will fall.
I did not realize that the fall in birth rates was already causing the overall  growth rate to slow. I consider this very good news. Until we have the technology to support all of those people without further trashing the planet, we should keep our population down. Some people, though, find cause for worry in these numbers. Wise again:
In the long term—on the order of centuries—we could be looking at the literal extinction of humanity. That might sound like an outrageous claim, but it comes down to simple math. According to a 2008 IIASA report, if the world stabilizes at a total fertility rate of 1.5—where Europe is today—then by 2200 the global population will fall to half of what it is today. By 2300, it’ll barely scratch 1 billion.
Why are we anguishing now about falling populations in the year 2300? Who knows what life will be like then? How can we know that current trends will continue for 200 years? Could anyone 200 years ago have predicted the history of the modern era? Please. Of all the things to worry about, whether people will be having enough babies in the year 2300 seems to me to be one of the silliest.

3 comments:

Anonymous said...

Note that only the "rate" is coming down, not the real increase. The total number of people has grown at a steady linear rate for fifty years, consistently adding at least 70,000,000 people every year. If you always add seventy million to a cumulative total then of course the "rate" goes down, but it's not because the total decreases it's because the total keeps growing.

David said...

Why worry, indeed. By 2300, we'll be able to synthesize babies in our Mac 5,000,000.1s (option: add a Yahoo toolbar).

Anonymous, as a larger and larger portion of the population becomes elderly, I imagine the world death rate will eventually rise above 70,000,000/year, which will start the world population number to fall, even if your 70,000,000 new people/year figure remains constant.

Graham Lester said...

It's silly to assume that falling population rates will inevitably lead to extinction. The only way that could happen would be if billions of people made a rational decision that life was not gratifying enough to be worth passing on to the next generation. In short, we can only depopulate ourselves to extinction if we *want* to.