Can we stop worrying about Malthus?

My friend Charles Kenny has an article in the current Foreign Policy magazine in which he wrote that Thomas Malthus' "predictions have been wrong from the start." In spite of the billion people in the world who are hungry, Charles is right that it is still possible to feed the world's population and that resources should be sufficient to feed the world for decades to come. Why are we not now running out of food, according to the current ideas:

• Population growth has abated. Birth control technology has improved greatly. People's desired family size has gone down, in part because improved quality of life and health care technology have increased survival rates.
• Food production has increased radically, in part because of more land being used to produce food and in part because food production technology has been radically improved. More energy is being used to produce food, and food distribution has improved.

Importantly, policies and institutions to reduce population growth and increase food supplies have been introduced and strengthened worldwide.

Are there threats to the success in forestalling Malthusian famine? I would suggest that there are if we think in a time scale of generations or centuries.

• Food supplies could fail to grow sufficiently. Agricultural research is lagging and there may be limits of plant productivity that we will find in the future. Energy supplies might fail to meet future needs. Environmental problems ranging from soil loss to climate change, from desertification to failure of water supplies might limit food production.
• Population growth rates might increase again. The reduction of preferred family size could change on a global level, especially since the trends of the 20th century are relatively recent in terms of the history of the human race. So too, radical increases in life expectancy (reduced death rates at older ages) could result in both increasing dependency ratios and increased rates of population growth.

Perhaps most of concern would be a failure in policy. The policies used in reducing population growth have ranged from modest to the draconian Chinese policy of one child per family. If governments come to believe that the Malthusian prediction is unreal, or if policy fatigue were to set in, birth rates could again increase. Alternatively, policies that promote the increase of food production could fail, or policies to prevent environmental degradation reducing food production could fail.

Malthus had an important intuition some 200 years ago, albeit one that was far less than complete and was wrong in many details. Svante Arrhenius a century ago perceived that carbon dioxide was a greenhouse gas and its accumulation in the atmosphere could lead to global warming. His intuition, similar to that of Malthus, lead to a vast amount of research which greatly clarified the situation. The limitations of either man's foresight should not be confused with challenge to the fundamental insight.

There have been famines in the past, and indeed I am old enough to recall the time before the Asian Green Revolution when people discussed triage strategies to deal with Malthusian hunger. We can see signs of global warming in the sequence if very warm years in the past decade. I take these events to be indications of the need for strong policies to prevent worsening of global hunger and climate change over the long run. The fact that a century or two has passed without cataclysmic disaster does not mean that the need for good policies is over.