Most people know the Reverend Thomas Malthus as the English clergyman and economist who wrote The Principle of Population, a work that went through six editions between 1798 and 1826 and that made the case that “The power of population is so superior to the power of the earth to produce subsistence for man, that premature death must in some shape or other visit the human race.” In the more than two centuries since the publication of Malthus’s first edition a raft of biological and social scientists have attempted to refute Malthus’s basic theory, pointing out as the enviro-sceptic Bjorn Lomburg did, that food production has always increased faster than population growth.

For the moment, these “skeptics” have been correct. If population growth continues, in the long run, they will all be wrong. Why? Because even if our vaunted technology gets to the point of turning all matter and/or energy into the food and support necessary for human existence, the amount of matter on the planet is indeed finite, although in practical terms, it’s far more likely that other aspects of civilization will collapse first, leading to a reduction in food supply… and population.

The larger mistake in dealing with Malthusian economics, however, lies in the failure of Malthus’s critics to understand why Malthus did not seem to be correct in his own lifetime, or even in ours. Both Darwin and Wallace read The Principle of Population, and both commented to the effect that his work applied directly to the “natural world.” What they meant was that, for example, there are always more prey than predators, because if there aren’t, predator populations crash. The same is true of herbivores. One of the problems the giant panda faces is that it’s a very picky eater and there is only so much of the bamboo it eats within its range, and that range is decreasing because the human population has been encroaching.

In overall terms, what the human species has done for roughly the last 8,000 years is to employ technology to transform the entire world ecology into anything but a “natural” world. Currently, there are between one and one and a half billion cows in the world, 15 billion chickens, 700 million pigs, over 100 million horses, mules, and donkeys, and close to half a billion domesticated turkeys and geese. None of these animal population levels are anything close to what these species could maintain without extensive human effort, and the impact of these animals is anything but insignificant, considering that, as just one example, a single cow produces 250-500 liters of methane every single day, and that methane tends to last in the atmosphere for up to 100 years. Fertilizer run-off from the Mississippi River has created algae blooms and large dead zones in the Gulf of Mexico.

Years ago, when I was working at the EPA, research studies showed that the pesticide toxaphene, used primarily on cotton crops in the southern United States, was appearing in the tissues of northern arctic mammals — not birds who might have flown over or through the USA, and in animals who did not prey on such birds. While its use is now banned in the United States, the world-wide spread and bioaccumulation is indicative of just how much human technology has changed and modified the planet.

This human-created “ecology” is not stable, nor can it be maintained without enormous investments of energy, resources, and effort. So, while the human species has been able to “thwart” Malthusian principles for two hundred years, the real question is not how and why Malthus was wrong, but for how long we will both allow unchecked human population increases and increasingly artificial ecological manipulation… and at what cost.