Everything Everywhere Daily: History, Science, Geography & More - Human Life Expectancy

Starting point is 00:00:00 Everyone, I have some good news and some bad news. The bad news is that you, me, and everyone else listening to the sound of my voice right now are mortal. As of the recording of this episode, time is undefeated. But the good news is that there has never been a better time to be alive, and that historically speaking, human life expectancies are at an all-time high. Learn more about life expectancies throughout human history and the things that improve them on this episode of Everything, everywhere daily. What if your perceptions about the past were wrong? ThruLine is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively

Starting point is 00:00:56 turned day into night and how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. Before I begin, I should note the subtle yet important difference between the concepts of lifespan and life expectancy. They're two very similar concepts, but they're very different. Lifespan refers to how long the oldest members of a species can live. The maximum human lifespan appears to be around 115 to 120 years, depending on if you think Jean Clement actually lived to be 122, a subject that I covered in a previous episode.

Starting point is 00:01:38 Life expectancy is just the average length of life for a member of a species. It is literally just the mean value, for everyone in a population. Life expectancy, because it's an average, will always be lower than the theoretical lifespan. So, the discussion of human life expectancy has to start thousands of years ago in the Paleolithic Age. Genetically, someone who might have lived 20 or 30,000 years ago wasn't really that different

Starting point is 00:02:07 than you or me. However, their lives would have been totally different. In the words of the philosopher Thomas Hobbs, their lives were in the words of the philosopher Thomas Hobbes, their lives were probably poor, nasty, brutish, and short. Most of what we know for this period has to be cobbled together by archaeologists and from old human remains. From what we can tell, the average life expectancy at birth for someone who lived in the Paleolithic era was about 25 years, maybe getting as high as 30. When thinking about these ancient life expectancies, the difference between life expectancy and lifespan is really important. The fact that life expectancy was around the age of 25 to 30 didn't mean that 25-year-olds

Starting point is 00:02:50 were the equivalent of 85-year-olds today. What it meant is that a large number of children never reached adulthood. If you have two people, one who dies at the age of one and one who dies at the age of 70, then the average is 35. While we know that infant mortality was much higher in the distant past than it is today, we aren't exactly sure how high it was. there is disagreement on how to interpret the archaeological evidence. The evidence of high infant mortality comes from the large number of infant skeletons

Starting point is 00:03:21 compared to adult skeletons that have been found. One estimate places the infant mortality rate in the Paleolithic age as high as 40 to 50%, which, if true, is actually quite astonishing. However, another theory holds that while infant mortality was indeed high, the number of infant remains is more a reflection of high fertility. If you did manage to reach adulthood, then your odds of making it into your 40s or 50s weren't actually that bad. However, getting to what we call old age today was possible, but still not probable. And that's because there were a host of things that Paleolithic people had to worry about that we don't today.

Starting point is 00:04:00 One of the biggest was homicide. Evidence for this varies widely depending on where you find remains, but there are some places where the percentage of human remains that should show signs of blunt force trauma is over 50%. We like to think of nomadic hunter-gatherers as people who lived in a peaceful state of nature, but the evidence indicates that this was far from the case. Based on data derived from unearthed human remains, many estimates place the rate of homicides high as 20%, and in some places, even higher.

Starting point is 00:04:35 That is one in every five people whose life came to an end at the hands of another person. To put that into perspective, the odds of being killed by someone else, even in the places with the highest murder rates in the world today, are well below 1%. High rates of violence have been observed in other hunter-gatherer peoples over the last 200 years. One of the other major threats constantly looming over ancient people was starvation. A tribe of people would never be more than a bad hunt away from not having any food. A hard winter, a hot summer, a flood, a volcanic eruption, or any number of things could cause game to flee, making life difficult. One other thing observed in hunter-gatherers that probably exist in Paleolithic people was parasites and infections. These are conditions such as ringworm, hookworm, and other infections from cuts and scratches.

Starting point is 00:05:27 That being said, one thing that ancient people probably did not suffer from is communicable diseases. Many of the worst diseases that have plagued humanity have all come from domesticated animals. Prior to the domestication of animals, that vector of disease transmission simply wouldn't have existed. There's no evidence of Paleolithic or Neolithic smallpox, cholera, bubonic plague, or other similar diseases. Moreover, because people lived in smaller nomadic groups, there wasn't as much contact between groups, so communicable diseases couldn't easily spread. Going from the Paleolithic into the Neolithic and then into the advent of agriculture and the rise of civilization, something surprising happened to human life expectancy. It stayed pretty much the same.

Starting point is 00:06:15 The rise of agriculture and the development of complex large civilizations did not result in a market increase in average human life expectancy. You'd think that agriculture would have resulted in an increase in life expectancy, but it didn't by any. noticeable amount. What did happen was a shift in the threats and dangers that humans faced. Starvation remained a threat, but it was now a different kind of threat. In the past, you might have had a bad haunt, but if the game wasn't around, you and your clan could just move. But with the rise of farming, there was still the threat of a bad crop. Now pestilence and flooding were threats, and when a crop was bad, you couldn't just get up and move. However, you could store grain for use when you did have a bad crop.

Starting point is 00:07:01 Interpersonal or intertribal violence decreased with large states that could use the monopoly of violence to keep the peace. However, large-scale violence in the form of wars and conflicts between organized armies increased. When nomadic tribes fought each other, it was usually over scarce resources, and fights were often about extermination. With agriculture, most fights were about conquest. You didn't want to wipe out the farmers because they grew the crops that you could tax and demand tribute, in which you built your wealth. Communicable diseases proliferated as humans became settled and lived in closer proximity to animals. Trade routes transmitted diseases over wider areas and the first epidemics and

Starting point is 00:07:42 pandemics became possible. Childhood remained as dangerous as ever. We have even better data from the last 2,000 years, and there's a consistent pattern across pretty much every civilization. child mortality remained near 50% in ancient Rome, ancient Egypt, ancient China, Peru, medieval Europe, Aztec, Mexico, and many other cultures. High child mortality remained the norm almost everywhere in the world up through the 18th century. As such, human life expectancy remained in the low 30s all the way up to the beginning of the Industrial Revolution. Life expectancy did go up a bit in Europe after the Renaissance, but nothing dramatically. Life expectancy was still closer to what it was in the Paleolithic than it is today,

Starting point is 00:08:31 but it may have gotten as high as 35 or 37. Things began to change somewhat in the industrialized parts of the world beginning in the 19th century. However, again, the change wasn't dramatic. There was still a lot of urban squalor, living conditions were poor, and life in rural areas was very much the same as it had always been. By the start of the 20th century, the global average human life expectancy was still hovering around 30 years of age, despite modest gains in the 19th century. And then something started to happen in the 20th century. Life expectancies began increasing and increasing dramatically.

Starting point is 00:09:09 The rise in life expectancy wasn't evenly distributed around the world, but things did go up almost everywhere. By 1950, the global life expectancy was a lot of the world. expectancy across all countries had reached 54, and by 2020, the global average had reached the age of 73. By the 21st century, a human born on the planet Earth would live over twice as long as one born just a hundred years earlier. This was after thousands and thousands of years of little to no improvement in life expectancy. The place with the highest life expectancy today is Hong Kong at 85.3 years, and the country with the lowest life expectancy is the Central African Republic at 54 years. But a person born in the Central African Republic today will live almost twice as long

Starting point is 00:09:59 as somebody born in England in 1900. The increase in life expectancy was the driving force behind the rise of global population levels throughout the 20th century. It wasn't because more people were being born. It was because more people weren't dying. So what happened? Why did humans start living longer after tens of thousands of years? There isn't one single reason. There were a host of reasons which all worked in conjunction with each other. One of the first things had to do with the spread of sanitation. If you remember back to my episode on sewers, people used to live amidst filth. Sewers, indoor plumbing, and flush toilets were all innovations that improved cleanliness. and improved cleanliness cut down on a major transmission vector for the spread of disease.

Starting point is 00:10:48 One of the other big things was the development of the germ theory of disease. I've covered many stories that led up to the development of the germ theory of disease in previous episodes. Ignace Semmelweis learned the life-saving benefits of just washing your hands. John Snow managed to stop a cholera epidemic in London by identifying tainted water. Louis Pasteur figured out that you could kill germs through heat. I can't stress just how important the germ theory of disease was because it was the key that unlocked how to treat and prevent many diseases. If civilization were ever collapsed, maybe the one bit of knowledge we preserve is that germs cause disease. Working conditions also improved, which cut down on workplace accidents, and the improvements in safety eventually found their way to safety and consumer products.

Starting point is 00:11:38 Vaccines were developed that were able to stop many of the diseases that caused high-stained. child mortality. Smallpox, arguably the deadliest disease in history, was completely eradicated through vaccines. Antibiotics made it possible to treat many of the common illnesses that affected people. Food production increased dramatically, all but eliminating the threat of wide-scale famine today. Despite two of the most horrific wars in human history in the 20th century and many other lesser wars, deaths due to violence decreased dramatically. Energy usage increased, which is, highly correlated with standards of living. This was used for many things, including preserving foods, through freezing and refrigeration. And of course, I haven't even yet mentioned improved

Starting point is 00:12:21 medical care, techniques, and pharmaceuticals. A baby born today in all but the poorest countries now has an over 99% chance of reaching adulthood compared to just a 50% chance a few centuries ago. This has all resulted in a compression of the gap between life expectancy and the possible human lifespan. There are still significant advancements to be made, including increasing life expectancies in developing countries, but even there, things are improving. As I said at the start of this episode, now is the best time ever to be alive. All of us have the best odds ever of living a long, healthy, and productive life. The executive producer of Everything Everywhere Daily is Charles Daniel. The associate producers are Peter Bennett and Cameron Kiefer. I wanted to give a

Starting point is 00:13:14 Big thanks to everyone who supports the show on Patreon. Your support helps me put out a new show every day. And if you're interested in everything everywhere daily merchandise, Patreon is currently the only place where it's available. And if you'd like to talk to other listeners of the show and get notified to future episodes and projects, please join my Facebook group or Discord server. Links to everything are in the show notes.

Everything Everywhere Daily: History, Science, Geography & More - Human Life Expectancy

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