19 Scientists Who Have Saved the Most Lives

as we work at building a better future, let's dig in to how we got to where we are today

“One of the ultimate goals of science is mastery over nature, for the benefit of mankind.” 

It’s obvious enough that the narrative we get from media, politicians, celebrities, and even a lot of scientists is that things are bad — and getting worse with little chance of improvement — that it’s hardly worth mentioning. Pirate Wires readers will also know that, in reality, when you zoom out to look at the big picture, most of this doom and gloom is unwarranted. True, we do have problems, but the struggles our recent ancestors faced were bigger, and we can use the same tools they did — science and technology — to continue improving our lives.  

But when working to build a better future, it’s helpful to know how we got where we are today. In this post, we’re going to look at some of the scientists whose discoveries and inventions have helped humanity the most. Taken together, these geniuses saved billions of lives, and the existence of even more than that were made possible. And while there’s no way we can fit everyone who deserves to be here, we’ll look at a few of the most impactful and without whose work there’d be a good chance you wouldn’t even be alive to read this right now¹. 

Norman Borlaug: one billion lives saved

Norman Borlaug in 2004 / wheat | Images: Ben Zinner, USAID / kallerna

Discovery or invention: the Green Revolution / high yield wheat

American Norman Borlaug grew up on a farm in the early 1900s, and knew firsthand the difficulties of growing food. This led him to become an agronomist, aiming to develop better crop varieties. Working in Mexico, he created high yield, disease resistant wheat cultivars. Unlike other crops at the time, Borlaug’s wheat wasn’t sensitive to day length, and could be grown around the world regardless of latitude and climate. Even better, it was a dwarf wheat. Borlaug’s early wheats were tall, like all other wheat at the time, and increasing yields made them top heavy and prone to falling over, which could dramatically reduce harvest yield. The tougher, shorter stems of the dwarf wheat were able to support bigger heads, directly less energy into stems and more into the the grass’ edible grains.

His work allowed Mexican wheat harvests to triple, and soon after, in the 1960s, averted famine in Pakistan and India. It served as a model for other scientists to develop similar varieties of other staple crops, such as rice, and thus initiated the Green Revolution, which set a precedent for global agricultural advancements. It’s hard to overstate how important to our modern world the Green Revolution has been. Without Norman Borlaug’s work, there is simply no way we could support eight billion people. 

Fritz Haber and Carl Bosch: 1 to 2 billion lives saved

Carl Bosch and Fritz Haber | Images: Public domain

Discovery or invention: synthetic nitrogen fertilizer

Nitrogen is vital for plant growth, and though it comprises ~78 percent of our atmosphere, it isn’t in a form that plants can use. This problem was ameliorated by adding a usable nitrogen source to crops — generally manure. But there simply wasn’t enough to go around. 

Scientists had been trying to artificially synthesize nitrogen compounds for use as fertilizer for about a century when the German Fritz Haber tackled it in 1894. A few years later he succeeded, producing a small amount of ammonia using exotic catalysts. Unfortunately, there were two main barriers to commercialization that had yet to be overcome: the catalysts were expensive and difficult to work with, and no large containers existed capable of withstanding the high pressures and temperatures the process needed. 

Enter Carl Bosch, also from Germany. First, he found an inexpensive iron catalyst that worked, then proceeded to scale up container sizes until he could synthesize ammonia in eight-meter (26-foot) vessels. In 1913, he opened the world’s first factory synthesizing ammonia, creating the fertilizer industry. 

Today about half the human population is fed using nitrogen fertilizer created by the Haber-Bosch process. Meaning about half the people reading this owe their existence to it. Cool implication: about half the nitrogen in our bodies—used to make DNA, RNA, and proteins—is from a synthetic source. 

Karl Landsteiner and Richard Lewisohn: 1 billion lives saved

Karl Landsteiner and Richard Lewisohn | Images: Public domain

Discovery or invention: practical blood transfusions

Before blood transfusions, people commonly bled to death from accidents, ulcers, and childbirth. Surgery was highly dangerous. Though animal-to-animal blood transfusions (and weirdly, animal-to-human too) had been performed in the 1600s, the first successful human-to-human blood transfusion that we have on record only happened in 1818. And while transfusions did save lives, they often induced fatal allergic reactions in the recipient. 

Nobody knew why, until in 1901 the American Karl Landsteiner discovered that blood had characteristics often making it incompatible with other blood. He christened these differences the A, B, and O blood types (other blood types were found later). This discovery made safe transfusions possible, and provided an explanation why many earlier attempts had failed. However, there was still no way to store blood, as it coagulated quickly once removed from the body. 

But in 1914, it was discovered that sodium citrate acted as an anticoagulant, and German-American surgeon Richard Lewisohn experimented to determine how much was needed to safely prevent blood from coagulating. It worked, thus producing storable blood, making blood banks and widespread transfusions practical for the first time. 

Alexander Fleming + team comprised of Howard Florey, Ernst Chain, and Norman Heatley: 200 million lives saved

Alexander Fleming, Howard Florey, Ernst Chain, and Norman Heatley | Images: Public domain

Discovery or invention: penicillin, the first antibiotic

Up until the first quarter of the 20^th century, a tiny scratch or blister could literally kill you, and too often did. Enter modern antibiotics, which begins with English researcher Alexander Fleming, notorious for having a messy lab. In 1928, returning from a family vacation, he noticed that some petri dishes of staphylococci bacteria were contaminated and ruined by a fungus belonging to the genus Penicillium. Fleming was intrigued, and discovered that the compound produced by the fungi, which he dubbed penicillin, killed bacteria. But producing a significant quantity of penicillin proved challenging, and lacking the resources to properly pursue it further, Fleming shelved his research. 

Thankfully, he carefully preserved samples of the fungi he had used, which later became the starting point for a team led by Australian pharmacologist Howard Florey, which was searching for antibacterial compounds. The team worked to extract and purify penicillin, and near the end of WW2 they succeeded. While penicillin has by itself saved about 200 million lives, it was just the first of many antibiotics, which have saved millions more.  

Edward Jenner: 150-200 million lives saved

Edward Jenner performing his first vaccination on James Phipps, a boy of age 8, on May 14, 1796 | Painting by Ernest Board / Public domain

Discovery or invention: smallpox vaccine, the first vaccine

Of all human maladies, smallpox may have been the worst. The disease was fatal in for 20 to 30 percent of its victims, and in the century before its elimination, smallpox killed half a billion people, 300 million of them in the 20^th century alone. 

In 1796 English doctor Edward Jenner noticed a curious phenomenon: milkmaids never seemed to get smallpox. Instead, they got a mild illness from cows — aptly named cowpox — which Jenner hypothesized protected against smallpox. To test this, he took puss from a cowpox sore on an infected milkmaid and used it to inoculate a nine-year-old boy. A few months later, Jenner exposed the boy to smallpox and found he was immune. Publishing his discovery, he wrote that, “the annihilation of the smallpox, the most dreadful scourge of the human species, must be the final result [of vaccination].” 

179 years later, Jenner’s hope was fulfilled when the World Health Organization declared smallpox eradicated in 1980. Through this first vaccine, Edward Jenner laid the foundation for all vaccines, which have collectively saved over a billion lives. 

Frederick Banting, Charles Best, James Collip, and John Macleod: 200 million lives saved

Charles Best, Frederick Banting, James Collip, and John Macleod | Images: Public domain

Discovery or invention: insulin for diabetes

Before the discovery of insulin, diabetes was often a death sentence; particularly for children. That changed in 1922 with insulin — the world’s first miracle drug. 

It started when Frederick Banting, a Canadian physician with no research experience, approached the Scottish biochemist John Macleod, who was running a lab at the University of Toronto, with his idea that the pancreas produced a compound that could treat diabetes. His dedication was inspired by a childhood friend’s death from diabetes, and he convinced Macleod to let him begin experiments in his lab. He was assisted by American-Canadian scientist Charles Best, who had just completed his undergraduate degree, and chose medical research over a promising career as a professional baseball player. By the summer of 1921 they had discovered insulin, originally named “isletin.” But they had difficulty refining and purifying it, so Macleod brought in James Collip, a Canadian biochemist, to assist. Together they rapidly succeeded, and after Banting and Best tested insulin on themselves for safety, they saved the life of a diabetic child who was near death’s door. It wasn’t long before insulin was being mass produced and saving millions of lives. 

Abel Wolman, and Linn Enslow: over 180 million lives saved

Abel Wolman | Image: National Library of Medicine

Discovery or invention: practical water chlorination

Today, in developed countries, we take safe water for granted. While there is a whole elaborate process by which water treatment plants cleanse water, chlorination — which kills bacteria and other microbes — is a vital part of the flow. 

In the early 20^th century, the idea of disinfecting water with chlorine had been around for a while, with a paper on using it published in the 1820s, and a few places in Europe and the U.S. chlorinating water by the mid 1800s. However, most cities and towns were reluctant to use chlorine, and those that did often used incorrect dosages, which which lead to disease and death — while it’s excellent at killing microbes, in the wrong amount chlorine could easily kill humans too. American Engineer Abel Wolman and chemist Linn Enslow together set out to solve this problem. They successfully calculated exactly how much was needed for different water chemistries and bacterial loads, all the while keeping it at a safe level for humans. Though it took over 20 years to convince most municipalities in America to chlorinate their water, the pair's efforts paid off, and incidences of typhoid and other waterborne diseases plummeted. 

Louis Pasteur: hundreds of millions of lives saved

Louis Pasteur | Image: Public domain

Discovery or invention: germ theory of disease, pasteurization, vaccines for anthrax and rabies

Louis Pasteur was a French chemist and microbiologist who in the 1850s and 1860s made wide-ranging contributions to science. To start, he disproved spontaneous generation, the idea that life spontaneously develops from nonliving matter, and replaced it with the (correct) germ theory of disease. This alone has hugely impacted modern medicine, and helped lay the foundation for a better understanding of vaccines— he went on to develop two, for anthrax and rabies— and later of antibiotics. 

Once the germ theory of disease was in place, he realized that by heating liquids and foods (think canning), they could be sterilized to reduce or prevent spoilage. This process became known as pasteurization, and is still used globally to make food and drink safer for human consumption. Pasteur became known as the father of microbiology for his contributions, which have saved hundreds of millions of lives at least. 

Enrico Fermi: 2 million lives saved (potential for far more)

Enrico Fermi | Image: Public domain

Discovery or invention: first nuclear reactor

At first glance, a “mere” two million lives saved might seem a tad low for this article. But I want to include nuclear power because of its potential, and as a cautionary tale that just because something with lifesaving potential is invented, it doesn’t automatically mean it gets used. There are millions of deaths annually from air pollution, and widespread use of nuclear energy could stop most of them. 

Enrico Fermi (later of Manhattan Project and Fermi Paradox fame) was an Italian physicist who won the Nobel Prize for showing neutron bombardment could cause transmutation of elements, and that splitting uranium in this manner produced new and formerly unknown elements. Afterwards in America, he realized that a chain reaction could be set up with fissioning uranium, releasing enormous amounts of energy. Fermi then led the team which created the world’s first nuclear reactor at the University of Chicago, dubbed the “Chicago Pile-1.” This in turn paved the way for practical nuclear power plants, and the abundant and stable energy they provide. 

Willis Carrier: two million lives saved (potential for far more)

Willis Carrier | Image: Public domain

Discovery or invention: modern air conditioning

Similar to nuclear power, air conditioning has only saved a couple million lives thus far. But it has the potential to save many more. According to the Lancet, extreme heat kills around 350,000 people every year — air conditioning could save most of them. And though that same article argues, quite insanely, against the increased use of air conditioning because of climate change and inequality, in a warming world, air conditioning is the perfect adaptation.

The American engineer Willis Carrier didn’t originally set out to invent air conditioning per se. In 1902, the company he worked for, which made steam engines and pumps, was asked to design a way of controlling humidity inside a printing factory. Carrier was put in charge, and went above and beyond what was asked. His machine not only controlled humidity, but air circulation and temperature too. The invention was patented by Carrier in 1906, and modern air conditioning, originally an “apparatus for treating air” was born. 

-Owen Lewis

1. You may be wondering how these numbers are calculated. First off, I try to ensure its clear when I'm talking about lives saved versus lives enabled. Artificial fertilizer is a good example. It likely saved between one and two billion lives by reducing hunger, nutrition and starvation, whereas it enabled around four billion lives, given the present population. To put it another way, those one to two billion would have died had artificial fertilizers not been invented, whereas four billion people today world would not have been born. While it's tricky to put hard numbers to lives saved, I consider anything that prevents a death at any age to count. Some of this is easy, like seeing mortality drop to zero from smallpox. Some is a lot less exact, like lives saved by various means resulting in an increased life expectancy, which has more than doubled since 1900. I didn't calculate these numbers myself, but tried to get them from a variety of reliable sources. Even so, take them with a grain of salt, plus or minus a few tens of percent in some cases.