Retro Review: Jared Diamond—Guns, Germs, and Steel: The Fates of Human Societies (Norton, 1997)

In 1972, Jared Diamond was researching bird evolution in New Guinea. While walking along a beach, he had an hour-long conversation with a local politician named Yali, who asked him, “Why is it that you white people developed so much cargo and brought it to New Guinea, but we black people had little cargo of our own?” (page 14)

We’ve known for a while that the answer has nothing to do with race or genetics. So what is it? Diamond thought on Yali’s question for more than two decades, and tried to answer it with his now-classic book Guns, Germs, and Steel, which celebrates its 25^th anniversary this year, and has been adapted into a PBS documentary series. Diamond’s answer is geography.

Guns, Germs, and Steel make what might be the definitive case that that geography matters. In that respect, Diamond is convincing, but his singular focus excludes other things that also matter. These include culture, institutions, psychology, and policy choices.

It is important to include these other factors because Yali’s question, and variations of it, are among the most important questions in the world. Humanity has made great progress in reducing poverty since 1800 or so. Since then, life expectancy has doubled and infant mortality is down by more than 90 percent. Average income is up 30-fold or so in the richer countries, and many poorer countries are catching up. Nothing like this has happened before in human history on a sustained basis.

Keeping this progress going is the 21^st century’s defining project, not least because there is still so much room for improvement.

When Yali and Diamond spoke in 1972, New Guinea’s per capita GDP was $294. That’s about 80 cents a day for the average person. In 2021, it was $2,916, or about $8 a day. That is a 10-fold increase in what is now less than a lifetime. Yet, there is still so far to go. The average person in the United States made about $190 a day in 2021, or about 23 times more than the average New Guinean. How can New Guineans reach or exceed that level of prosperity?

As of 2019, the most recent available data, more than 670 million people worldwide still live on $2.15 a day or less, which is the current threshold for extreme poverty. That is about 8.4 percent of global population, the lowest it’s ever been. While COVID-era data will likely show a temporary setback when it becomes available, even a global pandemic is unlikely to change the last two centuries’ fundamental trajectory.

But that’s still 670 million people. Roughly twice the population of the United States is still living without electricity, modern sanitation, education, decent medical care, and other things even poorer people in the richer countries take for granted.

If we can understand what made the rich countries rich, we can better understand how those 700 million people can leave extreme poverty.

One thing holding Diamond back from this project is that he seems at least as concerned with fighting inequality as he is with fighting poverty; those are different things. Fighting inequality is concerned with mathematical ratios, whereas fighting poverty is concerned with making people better off. One of them is ethically irrelevant, the other ethically paramount. But whether you prioritize ratios or people, Diamond shows that geography is an important part of both worldviews. You need not share his ideological priors to gain insights into Yali’s question.

If you look at a map of the world, one thing that immediately stands out is that the Eurasian landmass’ dominant axis runs horizontally, from East to West. Africa and the Americas both have a vertical North-South orientation. This, Diamond shows, is important for why Europeans were the first to develop guns, germs, and steel. Geography is why Europeans colonized Africa and the Americas, not the other way around.

Eurasia’s horizontal orientation means that it has a massive belt of temperate climate stretching for about 9,000 miles, all the way from the Atlantic to the Pacific. That means that similar crops can grow over massive areas. When people figured out how to domesticate just a few calorie-dense temperate-zone crops like wheat and legumes, they could spread widely.

That was not possible in Africa, the Americas, or Oceania. Many parts of those regions lack temperate zones and depend on less nutritive tropical crops, like plantains or yams. North America’s large temperate belt mainly grew maize before Columbus, which is less nutritious than Eurasian crops. Maize-centered diets leave people vulnerable to pellagra if they do not get nutrients like niacin and tryptophan from other food sources.

Eurasia’s East-West temperate belt is also good economic—not just good gastronomic—luck. It makes trade networks easier to build. That is one reason why there was no vertical American or African equivalent to the horizontal Silk Road that connected temperate-zone Asian and European traders.

Easy calories and easy trade enabled the rise of villages, then cities. These population centers enabled specialization and exchange, which led to better technology over time. Geography gave Eurasian civilizations a technological head start on developing the guns and the steel from Diamond’s title that they needed to colonize the rest of the world.

Geography also has to do with germs. Once again, this is due more to chance than anything else; most domesticable wild animals happened to be on the Eurasian landmass. Our most common domestic animals have Eurasian origins, including horses, pigs, cows, cats, and dogs. Native American civilizations domesticated no large species besides llamas and alpacas, which are not strong enough to bear large loads or drive plows like camels, oxen, or horses. While wild Eurasian horses and pigs are domesticable, their African relatives, such as zebras and warthogs, are not.

That matters for diseases because, as many people learned during the COVID-19 pandemic, some diseases can hop across species. When people took animals into their homes and villages, they also took in their diseases, some of which were zoonotic. This shows in the very name of some diseases like chicken pox and cow pox.

The early rates of sickness and death from animal domestication must have been brutal, especially without a germ theory to explain why it was happening. But over time, the human versions of diseases like influenza, malaria, and smallpox became endemic and (usually) non-lethal. High disease mortality was part of the price of settled life, but survivors developed substantial immunities.

Thousands of years later, when the Old World met the New World using its guns and steel, Eurasian germs came along for the ride. That didn’t matter much for Europeans and their built-up immunities, but it mattered a great deal for indigenous Americans who had never been exposed to European diseases. As many as 90 percent of some native populations perished from disease in the first generations after contact.

That, Diamond argues, is how geography can explain why guns, germs, and steel arose when and where they did, and why Eurasian civilizations were the colonizers and not the colonized. It is a convincing story, and an important part of the answer to Yali’s question.

But it is not the whole answer. The drawback to Guns, Germs, and Steel is that it is, at heart, a single-variable answer to a multi-variable question. It remains essential reading 25 years after publication, especially for those who think that the right economic policies are the single variable that can answer Yali’s question. But because of Guns, Germs, and Steel’s narrow focus, readers interested in helping to fight global poverty should treat Diamond as only part of the answer.

A good place to turn for a more holistic approach is Mark Koyama’s and Jared Rubin’s short and readable How the World Became Rich: The Historical Origins of Economic Growth, which shows how all of the important growth engines work together. In addition to geography, they answer Yali’s question with cultural attitudes to openness, progress, and commerce; political and social institutions; population growth; and relatively market-oriented economic policies. No single one of these things enriched the world. All of them interacting did—and the process is still ongoing.

They also argue that colonialism and slavery made the world poorer. The old wealth-through-exploitation model turns out to be a dud. Colonialism certainly enriched individual monarchs and East India Company shareholders, but they were also costly vanity projects that made societies as a whole poorer. Empires use up more military and economic resources than they yield, which Adam Smith and several Americans pointed out in 1776, and as the Spanish and Dutch found out the hard way a century before Smith.

Diamond’s other analytical shortcomings are his determinism, his Malthusianism, and his overemphasis on that old empirical economic exploitation. It is significant that the subtitle to Guns, Germs, and Steel is the deterministic-sounding The Fates of Human Societies, and that its follow-up volumes are 2011’s climate- and population-themed Collapse, and 2019’s Upheaval, which is about how societies can recover from upcoming crises.

A good antidote to Diamond’s pessimism is Marian Tupy and Gale Pooley’s Superabundance: The Story of Population Growth, Innovation, and Human Flourishing on an Infinitely Bountiful Planet. Tupy and Pooleshow the astonishing extent of the modern wealth explosion. Like Koyama and Rubin, they offer multi-causal insights into its origins. They also offer insights into why many people, including Diamond, tend to be pessimists about the future, despite overwhelming evidence to the contrary.

Geography matters, but it is no longer destiny. As Julian Simon pointed out, the human mind is the ultimate resource. It has learned how to cross oceans, fly over mountains, desalinize ocean water, stay cool in summer and warm in winter, and connect global trading networks. There are only so many atoms in the world, but there are nearly infinite ways to arrange them. While Diamond is right that the orientation of continents matters more than most people think, we have also reached a point in history where other things matter much more.