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Thursday, August 21, 2008

"Are Malthus's Predicted Food Shortages Coming True?"

Jeff Sachs asks, "Have we beaten Malthus?":

Are Malthus's Predicted 1798 Food Shortages Coming True?, by Jeffrey D. Sachs, Scientific American: In 1798 Thomas Robert Malthus famously predicted that short-term gains in living standards would inevitably be undermined as human population growth outstripped food production, and thereby drive living standards back toward subsistence. We were, he argued, condemned by the tendency of population to grow geometrically while food production would increase only arithmetically.

For 200 years, economists have contended that Malthus overlooked technological advancement, which would allow human beings to keep ahead of the population curve. ...

Another factor undermining Malthus’s argument, it would seem, is ... demographic transition... Malthus did not reckon with the advance of public health, family planning, and modern contraception, which together with urbanization and other trends, would result in a dramatic decline in fertility rates to low levels... Perhaps the human population would avoid the tendency towards geometric growth altogether.

These critiques of Malthusian pessimism have long seemed irresistible. Indeed, when I trained in economics, Malthusian reasoning was a target of mockery, held up by my professors as an example of a naïve forecast gone wildly wrong. ...

Yet the Malthusian specter is not truly banished—indeed far from it. Our increase in know-how has not only been about getting more outputs for the same inputs, but also about our ability to mine the Earth for more inputs. The first Industrial Revolution began with the use of fossil fuel, specifically coal... Humanity harnessed geological deposits of ... coal, oil, and gas... We learned to dig deeper for minerals, fish the oceans with larger nets, divert rivers with greater dams and canals,... and cut down forests with more powerful land-clearing equipment. ... Much of what we call “income,” in the true sense of adding value from economic activity, is actually depletion instead, or the running down of natural capital.

And although family planning and contraception have indeed secured a low fertility rate in most parts of the world, the overall fertility rate remains at 2.6, far above replacement. ... According to the medium-fertility forecast of the United Nations Population Division we are on course for 9.2 billion people by mid-century.

If we indeed run out of inexpensive oil and fall short of food, deplete our fossil groundwater and destroy remaining rainforests, and gut the oceans and fill the atmosphere with greenhouse gases that tip the earth’s climate into a runaway hothouse with rising ocean levels, we might yet confirm the Malthusian curse. Yet none of this is inevitable...

In the coming decades we will have to convert to solar power and safe nuclear power... Know-how will have to be applied to long-mileage automobiles, water-efficient farming, and green buildings... We will need to re-think modern diets and urban design to achieve healthier lifestyles that also cut down on energy-intensive consumption patterns. And we will have to help Africa and other regions to speed the demographic transition to replacement fertility levels, in order to stabilize the global population at around 8 billion.

There is nothing in such a sustainable scenario that violates the Earth’s resource constraints or energy availability. Yet we are definitely not yet on such a sustainable trajectory... We will need new policies to push markets in a sustainable manner (for example, taxes on carbon to reduce greenhouse gas emissions) and to promote technological advances in resource saving rather than resource mining. ...

Have we beaten Malthus? After two centuries, we still do not really know.

    Posted by on Thursday, August 21, 2008 at 12:15 PM in Environment | Permalink  TrackBack (0)  Comments (19)


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