Nine billion or bust!

The peak of world population growth is in sight. Is Gaia breathing a sigh of relief?

Published December 12, 2006 6:52PM (EST)

The best current guess is that the world's population will peak at 9.2 billion around the year 2075. The bulk of that growth is expected to occur before 2050. To put that into a little perspective, my 12-year-old daughter's life is likely to encompass the most critical stretch in humanity's history on this planet -- that period in which we find out whether the earth can sustainably support our maximum population.

Here's a related datum. 30 years ago, only 4 percent of the population of the world's developing countries consumed an average of 2700 kilocalories worth of food per day. Today that number is up to 51 percent, and by 2050, it may hit 90 percent. In terms of addressing the problem of world hunger, this will be an extraordinary, unprecedented triumph. The prospects are less rosy when viewed in the context of the pressures exerted on the world's ecosystems. Because even as population stabilizes, per capita consumption will continue to rise.

These figures are drawn from the first chapter of "World agriculture: towards 2030/2050: Interim Report" from the Food and Agriculture Organization of the United Nations. (Thanks to Biopact for the link.) The seven-page overview is useful reading for anyone trying to get a sense of the Big Picture. The challenges faced by humanity in the 21st century are mighty indeed: climate change, peak oil, war and terrorism and who knows what devil's concoction of bird flu and species extinction and environmental degradation. But we shouldn't lose sight of the backdrop against which our efforts to meet these challenges are taking place. The proportion of the world's population that is malnourished or starving is dropping, and the overall population is set to stabilize in a matter of decades, which means that if current trends continue, the absolute number of malnourished people in the world will also start to decline.

Yesterday's reader discussion of the tensions between the world views expressed by technological optimists of the Norman Borlaug stripe, who believe an unending "green revolution" will keep allowing humanity to escape the consequences of its own proliferation, and those who believe that sustainability requires a comprehensive change in how humans live on this planet, inevitably led to the invocation of the ultimate prophet of doom, Thomas Malthus. Some believe we are already well past the breaking point of how many humans the planet can support. Others believe that further technological innovations will only prolong the inevitable reckoning. It's an argument that's been raging for at least 200 years, and the addition of another three billion or so humans to the total already living on the planet in the next fifty or sixty years is going to keep the debate hopping quite nicely.

But what I draw from the U.N.'s report is that this is a question that may well have an answer. As population and per capita consumption stabilize by the middle of this century, my daughter will have a pretty good idea of whether Malthus was right, or finally, absolutely, indubitably wrong.

Of course, whether proved right or wrong, adequate resources for the survival of humanity does not automatically imply that those resources will be adequately distributed. Let's give the U.N. the last word.

The slowdown in world population growth and the attainment of a peak of total population shortly after the middle of this century will certainly contribute to easing the rate at which pressures are mounting on resources and the broader environment from the expansion and intensification of agriculture. However, getting from here to there still involves quantum jumps in the production of several commodities. Moreover, the mounting pressures will be increasingly concentrated in countries with persisting low food consumption levels, high population growth rates and often poor agricultural resource endowments. The result could well be enhanced risk of persistent food insecurity for a long time to come in a number of countries in the midst of a world with adequate food supplies and the potential to produce more.

By Andrew Leonard

Andrew Leonard is a staff writer at Salon. On Twitter, @koxinga21.

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