Paul Ehrlich: The man who bet England wouldn’t exist by the year 2000

BBC Sounds Music Radio Podcasts Hello and thanks for downloading the More or Less podcast, with a programme that looks at the numbers and the news, in life and in apocalyptic predictions. I'm Charlotte McDonald. As cataclysmic openings to works of popular environmentalism go, you can't do much better than this. The battle to feed all of humanity is over. In the 1970s and 1980s, hundreds of millions of people will starve to death in spite of any crash programmes embarked upon now. At this late date, nothing can prevent a substantial increase in the world's death rate. That's the opening of a book called The Population Bomb, first published in 1968. Its author, the US biologist and environmentalist Professor Paul Ehrlich, died last week. The argument in the book was simple. The global population was growing faster than our capacity to produce enough food to feed everyone. Famine, disease and nuclear armageddon would follow if the population was not controlled. It made Ehrlich famous. This book was a bestseller and he used his celebrity to offer stark warnings about the future of humanity. We have an extremely serious world demographic situation. The population situation is bad beyond what any demographer even dreamed of 25 years ago. Sometimes his warnings were quite vague in terms of the timescale, but other times not. He was reported as saying in 1968 that if current trends continued by the year 2000, the UK would be a small group of impoverished islands inhabited by some 70 million hungry people. If I were a gambler, he said, I would take even money that England will not exist in the year 2000. Well, the UK still appears to be here. So, what went wrong with Paul Ehrlich's predictions of a population apocalypse? Paul Ehrlich started his academic career as an insect biologist. This says Professor Vincent Geloso from George Mason University in the US is important in understanding his logic. He very much understood the ecology of insects and essentially it came to permeate his thinking in that if you have too large of population of a certain group relative to the ecosystem it's in, it will collapse the ecosystem. Ehrlich wrote his book at a time when the human population was skyrocketing. There had been about a billion and a half people on the planet in 1900. By 1968, that had more than doubled to three and a half billion. Ehrlich predicted that rapid population growth would continue. Well, he actually was quite accurate about that. This is Darrell Bricker, the global CEO of Ipsos Public Affairs, who co-authored a book in 2023 titled Empty Planet, The Shock of Global Population Decline. It did go from three and a half billion people up to about 8.2 billion today. So, it did go through a rapid increase. But what he failed to notice is the elements that would start its future decline were already entrenching themselves and the biggest one being declining fertility, which he didn't really clock. If you're looking back through the UN data, they were already showing our global fertility are already peaked and it was already starting to come down. The UN predicted in 2024 that the global population will peak at just over 10 billion people in the mid-2080s, though Darrell thinks the real peak will be lower and sooner. But if Paul Ehrlich was half right about the population, he was dead wrong predicting that food production wouldn't be able to keep up. And you can sum up why he was wrong very easily. I mean, the Green Revolution effectively in two words. This is Peter Alexander, a professor of global food systems at the University of Edinburgh. Crop yields continue to improve really dramatically over that period from sort of the 60s, early 60s, you know, where if we look at the yields of cereals gone up something like 250% since 1961. That's right. The Green Revolution started before Ehrlich wrote his book when he stated that the battle to feed all of humanity is over. That battle was already being won. The Green Revolution is often associated with US agronomist Norman Borlog, who developed a high yield species of wheat, which when introduced to Mexico, India and Pakistan dramatically increased the amount of wheat they produced. But the Green Revolution is really thousands of farmers, scientists, business and governments doing all kinds of things. It's the breeding of the crops. It's inorganic fertilizer. It's pesticides. It's management practices. It's kind of a whole suite of different things that have been continually allowing us to produce more from less land. Peter says there obviously are environmental downsides to high intensity agriculture. But in terms of feeding the world's population, it seems to have done the trick. If you think about it in terms of calories produced, I did a very quick calculation and between 1961 and 2024, which is the most recent date I've got, per capita, we produced 34% more cereals than we did then. So while Ehrlich predicted ever more famine and starvation, the opposite has happened. Here's Darryl again. The ability to distribute food on a global basis has really improved as transportation and global trade have continued to expand. So what's happened along with the growth of the population has been the innovations and the adaptations that are necessary in order to feed that population. When you talk about global famine these days, there's a fair amount of speculation about what's going to happen as a result of climate change. But by far, the most famine in this world today that is created, because there is famine that does exist, is politically created. It's created by war. It's created by social unrest. It's not really created by the incapacity to be able to grow food. Ehrlich predicted an unstoppable and substantial increase in the global death rate. Instead, it's fallen. When he wrote his book, there were 17 deaths for every thousand people every year. There are now eight deaths per thousand per year. It was already falling when Ehrlich published his book. Paul Ehrlich's predictions proved wrong on multiple fronts. It might be technically true that we'll have a population collapse if we end up with more people than food to feed them. But the fact that it hasn't happened suggests something was missing from his ideas. For Vincent Gilosso, a free market economist, the bit that's missing is obvious. No, I don't think there ever was a strong justification for the idea that we would get overpopulation. The reason why is it omits the idea that humans are not only mouths that eat, but they're also creative minds that can create new resources and new ways to produce. So we can invent new ways to create crops, to use lands, to harness energy. So while there are environmental problems that need to be tackled, the ability of the human mind to find solution has led us to foil the predictions of Ehrlich. Ehrlich himself accepted in later life that some of his predictions didn't come to pass. That didn't stop him from continuing to predict terrible futures for humanity. But his arguments focus more on concerns about sustainability and biodiversity. Here he is in 2023 at the age of 90 on US program 60 Minutes. I know there's no political will to do any of the things that I'm concerned with, which is exactly why I and the vast majority of my colleagues think we've had it. That in the next few decades will be the end of the kind of civilization we're used to. Will that prediction come to pass? If you're only basing it on the accuracy of Paul Ehrlich's previous predictions, the chances are not great. That's it for this week. Thanks to Vincent Giloso, Peter Alexander and Daryl Bricker. Get in touch if you've seen a number in the news you think we should take a look at. Email more or less at bbc.co.uk. Until next week. Goodbye.