Why Aren’t We All Starving?

Why Malthus was wrong, and what it may tell us about the future

In 1798, Thomas Malthus made one of the most famous incorrect predictions in history.

You see, Malthus was living at a time of exploding population growth in England, and he worried that this increase would lead to disaster. He noted that the population of the British Isles was rising at a “geometrical ratio,” while its food supply was going up “arithmetically” — that is, the population was doubling every so often (1, 2, 4, 8, 16) while the food supply was increasing more slowly (1, 2, 3, 4, 5).

Malthus was sure that famine and pestilence were on the horizon, that people — especially the poor — would suffer terribly. This was, after all, the law of nature. When population outstrips food supply, awful things happen.

He was very wrong. When Malthus wrote his “Essay on the Principle of Population,” there were about one billion people on the planet. Over the next century, humanity doubled its population. In the next hundred years, we’ve added six billion more. And the percentage of people who are hungry — even in developing countries — has shrunk.

How could Malthus have gotten things so wrong?

What’s fascinating about his prediction is that he was mostly correct in describing the world around him based on past trends. The human population was growing quickly, and his predictions were in line with the iron laws that had governed agriculture for thousands of years. Based on what he knew about the world, his conclusions were understandable.

Malthus wasn’t incorrect in his observations about the world as it was, but he was wrong when he assumed that the world wouldn’t or couldn’t change. He failed to anticipate several developments in the nineteenth and twentieth centuries that would transform the world into a place very different from the one he was living in.

Malthus’ first mistake was his failure to imagine a world in which food could be produced much more efficiently than it was in his day. British farmers in 1798 were slightly more productive than their counterparts a century before — wheat yields in Britain were 1.26 tons/hectare in 1805, compared to .95 tons in 1705 and .74 tons in 1605. So Malthus was correctly describing the world around him when he said that the food supply tended to increase pretty gradually.

But look at what happened after 1800:

In the two centuries after Malthus wrote his “Essay,” British crop yields have octupled, and yields around the world have followed a similar track. We get a lot more food out of the land than we did in Malthus’ day. This is largely thanks to a series of discoveries and innovations that have made it possible for billions more people to live on the planet without starving.

These discoveries are not the type of science that gets the general public excited. There weren’t any charismatic, iconoclastic inventors or sexy consumer technologies. These innovations were way more boring than AI or jetpacks. But they were much more important.

First, in the middle of the 1800s, enterprising businesspeople realized that they could transport dried bird feces from Pacific islands near Peru to farms around the world. (I wrote a whole piece about this bizarre moment in history — check it out!)

Then, in the early 20th century, enterprising chemists Fritz Haber and Carl Bosch figured out how to pull nitrogen out of the atmosphere and turn it into a form that is usable by plants. Finally, in the middle of the 20th century, an Iowan agronomist (are there any two more boring words in the English language?) named Norman Borlaug developed new varieties of wheat that grow faster and produce more food than previous varieties. His research with wheat led to similar advances for other staple crops like rice.

How important were these discoveries? Well, science writer Vaclav Smil credits Haber-Bosch fertilizer with keeping about three billion humans alive today. Borlaug’s work is often estimated to have saved at least another billion human lives.

This isn’t to say that the invention of fertilizer and Borlaug’s “Green Revolution” were unalloyed positives. Fertilizer production uses a lot of energy, and fertilizer use contributes to climate change and damages water ecosystems. Green Revolution crops tend to be heavily dependent on chemical inputs like fertilizer and dangerous herbicides and pesticides. But they’re keeping half of humanity alive, so we can probably cut them a little slack.

And if we really wanted to be efficient in our farming and food distribution, we could easily feed many more people. We already produce 5,000 calories per day for each person on the planet — much more than we need. If we distributed it more fairly and wasted less of it, everyone would have more than enough to eat. If we got more of our calories from plants instead of animals, we could drastically reduce the land and carbon footprints of farming, as well.

We can probably forgive Malthus for failing to understand that scientists would change agriculture into something that farmers from 1798 wouldn’t recognize. But, were he here today, Malthus might say that innovations in farming alone without slower population growth would only delay the inevitable. At some point, food supply will be unable to keep up with relentless population growth.

Here’s where he was wrong a second time. Malthus assumed that the human population would keep doubling forever, failing to see how human behavior — especially around family planning — could change. He assumed that women would continue to have five or six children in perpetuity, meaning that population growth would never slow down (especially as better food and medicine lengthened people’s lives). Again, Malthus based this on the world around him — in 1798, high fertility rates had been the norm in pretty much every agricultural society in human history.

But his assumption wasn’t correct — over the century after Malthus wrote his manifesto, women gained more say in their reproductive decisions, became more economically powerful, and gained access to new methods of birth control. These combined to reduce the British fertility rate by more than half. Most of the world has followed suit since.

Malthus simply failed to imagine a world in which social norms around gender and marriage, along with scientific understanding of reproduction, would change as much as they did. The population would increase quite a bit, but it wasn’t destined to increase geometrically forever. Today, experts expect the global population to top out around 10–12 billion.

Malthus gets scoffed at a lot today — Nicholas Wade calls his “Essay” “an enduring source of error and self-bamboozlement for almost every day” since its publication in 1798. But, if you look at the information he had at the time, his predictions were reasonable. Nobody has a crystal ball.

The case of Thomas Malthus is an instructive one for us today, as we face another set of looming environmental disasters. What can we take away from his failures?

• First, and most importantly, it’s really hard to predict the future. We shouldn’t assume that we are locked into a fixed path. Human behavior can change, and new technology can transform the world. A combination of the two could radically change the future.
• But, then again, maybe they won’t. There’s no guarantee of a magical solution to our problems this time around. Putting all our hope in an improbable set of advances is probably foolhardy. We can’t just blithely assume that science will come along and save us every time.
• Speaking of science, progress is often made in boring ways, through unsexy technologies. If we manage to keep the worst-case environmental scenarios from happening, will it be because some celebrity genius invented a magical machine or because dedicated technologists kept chipping away at solutions like electricity grids, batteries, and solar technology, making them cheaper and more efficient?
• But — and this is important, too — the Cassandras are worth listening to. If Malthus had said in 1798 that population was outstripping food supply, but he was sure that somebody would someday invent technologies to solve the problem, he would’ve sounded ridiculous. Cassandras like Malthus are often wrong, but they serve a useful purpose: they help us understand the worst-case scenario. Their bleak predictions can at least make the seriousness of our problems clear and focus our minds on solutions.

So next time you have a meal — part of the stupendous modern bounty of food that Thomas Malthus never imagined possible — take a minute to wonder which of your assumptions about the world are wrong, and which future events might make you look like a fool.

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