Scatter, Adapt, and Remember: How Humans Will Survive a Mass Extinction

IN THE LAST two parts, we’ve looked at all the ways life on Earth, and especially humanity, have managed to survive hardships that ranged from meteorite strikes and megavolcanoes to the perils of migration and disease. Now we’ll turn to the stories of humans and other life-forms who have survived into the present day, using techniques that could serve us well as we make plans for a future world where our descendants can thrive. We’ll begin with the story of a group of humans, an ancient tribal people today called the Jews, who have retained a distinctive cultural identity for thousands of years. They’ve survived several deadly episodes of persecution in part by scattering and escaping in the face of adversity, rather than allowing themselves to be extinguished in the flames of war. In fact, this strategy of scattering is a crucial lesson taught to children during Passover, one of Judaism’s most important cultural rituals.

When I was the youngest kid at Passover gatherings, I was given the job of reading some questions that are a crucial part of the prayers. None of them made any sense to me, including the very first one: “Why is this night different from all other nights?” As I squirmed in my seat waiting for dinner, I hoped that the answers would explain why I had to eat such weird food, like parsley dipped in salt water and sweet apples mixed with eye-watering horseradish. After many years of grumpily contemplating why I had to eat things that symbolized the tears we shed during slavery, I figured out that Passover had nothing to do with dinner, and everything to do with memory. Passover is the one night every year when Jews retell the biblical story from Exodus about how the diaspora began. It’s become such an important ritual for Jews because the allegorical stories in Exodus mirror actual catastrophic events in Jewish history. This story of survival in the Bible became, in a sense, a template for survival in the real world.

But before we consider Jewish survival in recorded history, let’s recall the Passover story (apples and horseradish are optional). Thousands of years ago in ancient Egypt, the story goes, Jews lived as slaves under a cruel Pharaoh, making bricks for his pyramids and sorrowfully watching their families destroyed by backbreaking labor. Eventually a great leader came along, named Moses, and he begged the Pharaoh for his people’s freedom. When Pharaoh refused, he discovered that the single, incorporeal God of the Jews—so different from his people’s many half-animal gods—had some tricks up His sleeve. The God of the Jews sent ten plagues to devastate the Egyptian population, including crop-eating locusts, frogs falling from the sky, and a rain of blood (this always struck me as particularly awesome when I was a kid). In the worst of the plagues, God’s “angel of death” took the firstborn son from every house that wasn’t Jewish. Finally, the Pharaoh was persuaded. He told Moses to get his people out of the city, and the Jews spent one frantic day packing all their goods. They didn’t even have enough time to let their bread rise, which is why we symbolize this part of the story by eating a flatbread called matzo during Passover.

Apparently, at the last minute, the Pharaoh changed his mind about the whole deal and tried to send his soldiers after the fleeing Jews. That’s when Moses got superheroic, held out his hand, and parted the Red Sea. If you’ve ever seen Charlton Heston chewing the scenery in The Ten Commandments, you know what happened next. The Jews raced to the other side of the sea, hotly pursued by the Egyptian army. But once they’d reached the far shore, Moses let the waters smash back into their proper place, drowning the army and beginning the first chapter of the diaspora story.

For forty years, according to the Bible, the Jews wandered in the desert of what was then called Canaan, looking for a place to live. That’s when they became a diaspora people, a group far from their ancestral home and searching for a place to live where they wouldn’t be enslaved or worse. Later in the Bible, God leads the Jews to their “promised land,” eventually called Israel, which their children are destined to conquer. But the story of the book of Exodus ends with the Jews still in the desert, having won one battle but facing many more, unsure whether they’ll survive to find a home.

This ending is as significant as the structure of the story itself. It’s oddly realistic, leaving our main characters stranded in the middle of events whose outcome only their children will ever know. It suggests that when we struggle for a better life, we may never reap the benefits of that struggle ourselves. At the same time, the meat of the story is a powerful antidote to ancient tales glorifying war that were written during the same era as Exodus probably was. Stories about how cool it is to rip your enemies’ faces off appear elsewhere in the Bible (the books of Kings and Judges are complete bloodbaths), as well as in cuneiform tablets created by groups in the Assyrian empire and others. During a time in history when most nations celebrated military force and gory battles, the diaspora story in Exodus teaches us that there is great bravery in retreat. It is an act of tremendous strength to choose life and an uncertain future, rather than death in war. For the Jews who internalized this message, rather than the slaughter-is-nifty one, survival became a struggle that was often more difficult than death. But they lived. And so did their children, for generations that spanned millennia.

The First Diaspora

In modern parlance, the term “diaspora” refers to the geographical dispersion of people who are separated from their homeland. But, as political scientist William Safran explained in the first issue of the scholarly journal Diaspora, it can also refer to the diverse peoples who are the result of such a movement. Many groups have experienced a diaspora, including Africans outside Africa and Asians outside Asia, often due to some kind of major social upheaval. Today, these groups as well as Jews are commonly called diaspora peoples, even though many of them live in the same place that their families have for generations.

The word “diaspora” comes from ancient Greek, where it was first used to describe people who left their homelands to colonize distant regions. Gradually the term was applied to the Israelites of the era of the Babylonian exile, whose experiences were ironically the opposite of the original Greek meaning.

Though the rich geographical detail of the story in Exodus has led many to assume that it’s based on an actual historical event, archaeological excavations over the past few decades suggest that the story captures the spirit of the Israelites, but not their actual historical origins. UC Berkeley archaeologist Carol Redmount studies ancient Egyptian civilizations, and says there’s no evidence that the Jews or even their Asiatic ancestors were in Egypt during the time period described in Exodus—roughly during the reign of Rameses in the late second millennium BCE.

Instead, based on archaeological surveys of the region, it seems likely that the Jews during this time were a nomadic group whose members began to settle in small subsistence communities in the hills near Egypt at the height of the Bronze Age in the 1400s or 1300s BCE. Over the next several hundred years, these groups established many kingdoms, including a thriving northern region called Israel. But then in the eighth century BCE, Israel fell to the Assyrians and the formerly backwater southern kingdom of Judah rose to power. Judah’s biggest city, Jerusalem, once a hick town, became a thriving, walled metropolis hugging the base of the famous Temple Mount. It was also during this period that some archaeologists believe Jewish priests in Judah put the book of Exodus together from several sources.

Still, we don’t find archaeological evidence for a situation comparable to the one described in Exodus until the sixth century BCE. At that point, Judah had been a client state of Babylon for decades, and tensions between the two powers finally reached a breaking point. Judah revolted against the Babylonians and was completely crushed. In 587 BCE, the Babylonian king Nebuchadnezzar II led his troops into Jerusalem and destroyed it. Archaeologists have found sooty traces of a massive fire within the city’s walls from this era, along with countless arrowheads. The burning of the city sent many Jews into exile throughout the region, but within a few generations many returned to Jerusalem and assimilated into Babylonian society, adopting the local language, Aramaic, for writing. Indeed, in Jewish writings of the period, Judah is referred to by the Aramaic name Yehud. It’s also during this era that the nomadic hill people who created the nations of Israel and Judah started calling themselves Yehudim, or Jews.

One might argue that Jewish identity coalesced during a period when its nation was fragmented. And the Babylonian exile was just the first of many great fragmentations recorded in Jewish history. In the first century CE, Jews fled the Romans; in the fifteenth century, they raced to outrun representatives of the Spanish Inquisition; and still later, they abandoned large parts of Europe to escape the twentieth-century Holocaust. Passover has probably remained such an important ritual because it’s designed to remind Jews of our shared history as people who scatter in order to survive. To this day, we dwell in all the far-flung places where Jewish communities large and small continue to tell stories of a legendary time when we clung to life by running as far as we could, in as many directions as we could.

But is scattering really a good survival strategy outside of legends? If Jewish history is any guide, the answer is yes. Despite centuries of persecution and diaspora, there are people all over the world who call themselves Jews. And now we have scientific evidence that today’s Jews haven’t just inherited a cultural tradition. Some of us really do have biological ancestors who survived by wandering in the desert and beyond to find new homes. Population geneticists say there’s strong evidence that a group of Jews originating in ancient Rome over 2,500 years ago share identifiable genetic links with Jewish populations today from Spain, Syria, North Africa, Russia, and many other places. In other words, many Jews today owe their existence to people who scattered.

The Genetic Evidence for the Diaspora

Geneticist Harry Ostrer has contributed to one of the world’s largest and longest-running genetic studies of Jewish people. An energetic and talkative man, he collaborates with colleagues and subjects across the globe from a slightly cluttered office at the Albert Einstein College of Medicine, surrounded by family pictures and lab equipment. Located in a quiet neighborhood in the Bronx, the college is practically in the backyard of some of the groups Ostrer studies, like Brooklyn’s Syrian Jewish community, as well as a few Iraqi Jewish enclaves in Queens. He’s done work with a large group of Turkish Jews in Seattle, too.

Studying these groups and others has given Ostrer a perspective on the results of diaspora, rather than the events leading up to it. One point he emphasized strongly was that diaspora is more often about staying rather than scattering. Jewish history can be characterized by long periods of settlement and assimilation into local cultures, punctuated by sudden shifts when many people abruptly fled to new lands, usually to escape persecution. As geneticist David Goldstein notes in his book Jacob’s Legacy: A Genetic View of Jewish History, some of the earliest historical records of the Jews come from sixth-century BCE cuneiform tablets, which describe the Babylonian conquest of Jerusalem. But the results of that diaspora are lost to history. The next great Jewish settlement took place in Rome, and the diaspora that resulted has genetic echoes all the way up into the twenty-first century. The Roman diaspora is the focus of Ostrer’s research.

There are extensive records of Jewish culture from the Roman empire during the first century CE. Many of these Jews were brought to Rome as slaves starting in the second century BCE, from Greece, Judea (the former southern kingdom of Judah), and many areas in the region. Over the next century, Jews assimilated into Roman culture and became one of the biggest and most powerful minority groups in the empire. Though we have no reliable source for how many Jews there were in Rome, we know from contemporary sources that Judaism was a highly visible religion. Politicians issued laws regulating the practice of Judaism, and many Jews became Roman citizens. Meanwhile, in the courts, commentators often complained of Jewish “disturbances”—probably referring to political unrest in response to constantly shifting Roman rules about Jewish taxation and social status.

Unlike today, Roman Jews expanded the ranks of their temples by actively proselytizing. They assimilated into Roman life, but Romans assimilated into Jewish traditions, too. It was a time of great cultural mixing that finally came to an end in the late first century CE, when Emperor Claudius ordered all Jews to be expelled from Rome. A few years later, some Jews in Jerusalem rebelled against the Roman control of their city and were defeated, while Roman Jews fled their homes to avoid death or worse. In the Bible, this period is referred to as the time of the Second Temple’s destruction because the Romans destroyed the house of worship on the Temple Mount just as the Babylonians had over 600 years before.

Though this diaspora survives in historical documents and biblical stories, Ostrer wanted to know if he could track down evidence of a direct genetic connection between the Jews who left ancient Rome and the Jews alive today. To find out, he had to get DNA samples from hundreds of Jews across the world, looking for genetic commonalities. “I went to Rome and did recruitment there,” Ostrer recalled. “That’s been a stable community for hundreds of years and perhaps dates back to the community that was there in classical antiquity.” He also got samples from Eastern European Jews as well as Jews in immigrant communities in the New York area. Anybody who could trace their Jewish ancestry back two generations to all four of their grandparents was eligible to participate.

Once he’d amassed his samples, Ostrer and his team had the beginnings of what they call the Jewish HapMap. “Hap” is short for “haplotype,” a term geneticists use to describe a set of unique genetic markers in the human genome. People who share haplotypes are more closely related to one another than people who don’t, and Ostrer wanted to know whether he could identify distinctly Jewish haplotypes. Over several years, the researchers at the Jewish HapMap Project scoured their data using a variety of statistical methods to compare both short and long strands of DNA from volunteers. They began to see patterns suggesting that people who had lived close together centuries ago still shared genetic similarities. Jews in Central Europe today share more genetically with Jews in the Middle East than a non-Jewish person living in Central Europe does with a non-Jewish person in the Middle East. And it’s all because those groups of contemporary Jews had ancestors from the same regions of Rome. Discoveries like this demonstrated that there are distinctive Jewish haplotypes that offer hints about where people’s ancestors settled in the diaspora.

Once they had enough data, Ostrer and his colleagues could actually create genetic maps tracking the spread of Jewish haplotypes out of ancient Rome and into the Middle East and Europe. Why were they able to isolate these haplotypes at all, when so much time had passed? It had to do with a change in Jewish culture after the Roman diaspora. Jews in ancient Rome were proselytizers—they converted many people and intermarried with non-Jews regularly. The Jews of that era would probably have shared haplotypes with their Jupiter-worshipping neighbors. But after their expulsion from Rome and the destruction of Jerusalem in the first century CE, Jews changed the structure of their communities radically. No longer were they permitted to proselytize and intermarry. To be considered truly Jewish, a child had to be born of a Jewish mother, establishing a rigorous matrilineal line. Without realizing it, the Jews of the first century created a culture that allowed their unique haplotypes to endure over the next 2,000 years.

Mapping the diaspora becomes more difficult when you add in the evidence of extensive assimilation and intermarriage taking place in Europe before the Inquisition. In countries like Spain, Jews enjoyed a social status comparable to the one they had once held in ancient Rome. They were prominent members of their cities, intermarried with non-Jews, and dramatically expanded their communities. But the tide turned in the fourteenth century, which saw the rise of political persecution of Spanish Jews. This culminated in the fifteenth century as the Spanish Inquisition spread outward into Portugal and Rome, and once again sent Jews running into their familiar diaspora pattern, pushing them deeper into Europe and the East. Still, they survived and even retained some of their haplotypic particularities. A group of Portuguese anthropologists recently discovered a small group of Jews living in the mountains of Portugal whose ancestors had apparently fled there and masqueraded as Catholics to escape the Inquisition.

Despite what he and other geneticists have discovered, Ostrer is wary of saying too much about the genetic basis for Jewish identity. This is an area of inquiry that is still evolving rapidly, and he’s quite willing to admit that some of his conclusions are simply “a guesstimate.” There is no single haplotype that unites all Jews—instead, he and his team found four distinct haplotypes identified with different Jewish diaspora groups. There will never be a genetic “Jew or Not” test. All that Ostrer’s work reveals is that a genetically identifiable “Jewish people” survived the diaspora. We now have both historical and genetic evidence that scattering and hiding out during times of upheaval is a good way to ensure that your progeny will survive—even for dozens of generations.

The Black Atlantic

Toward the end of my conversation with Ostrer, we started talking about Jews today. We’re in the midst of another period of Jewish assimilation and migration, he said, making a sweeping gesture with his hands as if to encompass all of New York, or possibly the world. In the wake of nineteenth-century pogroms and the twentieth-century Holocaust, many Jews were forced to scatter to new areas. And some, like Reform Jews in the United States, have started converting people to Judaism again. The result of all this movement and intermixing is a Jew like me. My mother was a Methodist who converted to Judaism before she married my Jewish father. I was raised Jewish, but who knows what kind of haplotype I have? More to the point, when we’re talking about the survival of a group over centuries, does it really matter whether I’m culturally Jewish or genetically Jewish or somewhere in between? After hundreds of years of diaspora, aren’t all survivors a little bit hybrid?

This is exactly the question that people from many diaspora groups have raised over the past half century. Perhaps nowhere is the answer to it more beautifully expressed than in the book The Black Atlantic: Modernity and Double-Consciousness, by Guyanese-British scholar Paul Gilroy. While researching the often fragmented histories of blacks in England, Gilroy realized that he should reframe black identity as a hybrid experience that combines many cultures. To describe the origin of this experience, he called on the idea of a “black Atlantic,” the geographical region where African slaves were scattered in a forced diaspora across Europe and the Americas. Instead of having a single point of origin, like the lands around Jerusalem, Gilroy’s diaspora has many origins. And its survivors are genetic and cultural hybrids. But that doesn’t mean African identities have been extinguished in people outside Africa today. It has survived in a multitude of ways, though some of them might be unrecognizable to communities who lived in Africa half a millennium ago.

As Ostrer put it, diaspora is about where you come from, but it is also about where you end up. Our journeys change us radically, but when we settle down again there is a continuity, a shared history that holds us together. Jews and Africans are not unique in this respect—many groups have maintained a sense of community through times of hardship and separation. Recent human history teaches us that your group has a better chance of surviving in the long term if you’re willing to divide into groups and go your separate ways to safety. But that doesn’t mean the past is lost. What makes a book like The Black Atlantic so important is Gilroy’s powerful assertion that even if your group is unwillingly torn apart and assimilated into other cultures, your progeny will remember where they came from even hundreds of years from now.

The Passover ritual makes a similar assertion. It is a celebration of identity forged in diaspora, and a reminder that survival often means finding a new home. The difficult part, as we face an uncertain future, is how to understand the meaning of “a new home.” We may have to look very far afield to get our answers. In fact, one of the greatest stories of survival through adaptation does not come from humans at all. It comes from the humble blue-green algae, whose incredible history may also show us one possible path into the future.

YOU’VE PROBABLY CALLED it scum. But that slimy blue-green goo floating in ponds and on the ocean comes from a group of species so hardy that humanity’s fumbling attempts to adapt to our environments would be a joke to them. Well, it would be if these blobs of raw biological productivity had a mean sense of humor, or brains, or even mouths to laugh with. We’re talking about our old friend cyanobacteria, whom we met billions of years ago, in the first chapter of this book. At that time, it was busily unleashing enough oxygen to transform the composition of Earth’s atmosphere. Its subsequent 3.5-billion-year career as a life-form proves that this ancient breed of scum has gotten something fundamentally right. Cyano, as it is fondly known among scientists, evolved one of the planet’s greatest adaptations: photosynthesis, or the ability to convert light and water into chemical energy, releasing oxygen in the process.

Cyano has also had a secondary career as a biological building block for other life-forms. About 600 million years ago, sometime before the first multicellular life appeared, cyano began forming symbiotic relationships with other organisms, slowly merging with them over the millennia. Eventually these early cyano evolved inside other cells to become chloroplasts, tiny organs (known as organelles) that handle photosynthesis for plant cells. Every plant on Earth is, in fact, the result of this merging process. You can think of chloroplasts as both engines and batteries for plant cells; photosynthesis creates forms of energy that plants can use immediately as well as store for later. Cyano’s great adaptation is so powerful that plants and even a few animals like sea anemones have survived by absorbing cyano and turning it into their own adaptation.

Brett Neilan, a biologist at the University of New South Wales, has spent his life studying cyano among the ancient rocks of Australia’s coastline, and he thinks the secret to the algae’s success is simple. Cyano’s ancestors won the evolution game because they worked with what the Earth always had in good supply: sunshine, or some form of light, and water. Like most plants, cyano are called autotrophs, a word that means “self-feeding,” and refers to their ability to feed themselves without consuming other organisms. In a sense, cyano generate the food they consume. As a result, they can and do live everywhere. They’ve been found in Antarctica and in the boiling, acidic waters of Yellowstone’s geysers. Not only are they seemingly impervious to dramatic temperature changes, but they are virtually immune to famine as well. According to Neilan, cyano prevent themselves from starving in times of scarcity by storing extra nutrients like nitrogen in little sacs tucked inside their cellular walls. If these food caches are not enough, cyano can go into stasis. The microbes put themselves into a kind of suspended animation and can endure without food for years, waiting out droughts or other disasters that affect their food supply.

Cyano have other incredible abilities, too. They can live as individual single-celled organisms, but they can also join together with other cyano, Mighty Morphin Power Rangers–style, to form a multicellular creature. They are the simplest organism on Earth whose biological processes are regulated by the circadian rhythms of light and dark. Like humans, with our sleeping and waking cycles, cyanobacteria engage in different metabolic activities depending on whether it’s day or night. This allows them to engage in two separate chemical processes for nourishment—photosynthesis and nitrogen fixation—which would normally interfere with each other. Thanks to their circadian clocks, cyano can do photosynthesis by day and nitrogen fixation by night. They thus benefit from two kinds of nutrient production. Other plants benefit, too. Just as some organisms absorbed cyano to create choloroplasts, others have formed symbiotic relationships with the bacteria to reap the benefits of the energy produced by nitrogen fixation.

Cyano have succeeded so well on Earth because they create their own food, using a power source that is ubiquitous and sustainable. It’s such a good strategy that other life-forms learned from cyano’s success millions of years ago and absorbed these tiny engines into their own fuel-production processes. Humans may not be able to merge with cyano on a biological level—at least, not with current levels of technology—but many scientists are working on ways we could use photosynthesis to create more sustainable energy sources to help humans survive as a mass society.

Why Is Photosynthesis So Awesome?

One of these scientists is physicist-turned-biologist Himadri Pakrasi, who runs Washington University’s International Center for Advanced Renewable Energy and Sustainability (I-CARES). With a thatch of curly black hair just beginning to turn gray and a ready smile, Pakrasi radiates enthusiasm for his work. The first time I spoke to him, by phone, it was to find out how his lab had managed to create energy using water, light, and bacteria. “You should come out here and see!” he exclaimed. Very few scientists would invite a writer they’d never met before to visit their labs, but Pakrasi is the kind of guy who wants to get people engaged with his work—even strangers from halfway across the country. It was easy for me to understand how he’d built up a large international group of collaborators at Washington University, including scientists, city planners, and engineers.

When I arrived in St. Louis a couple of months later, Pakrasi told me that he’d been fascinated by photosynthesis his whole life. “Every plant is a fantastic power reactor,” he explained. “Let’s learn from nature how to do that ourselves. Let’s have a perpetual synthetic plant that makes energy.” He and his colleagues at I-CARES are convinced humans could be using algae to fuel our cities in a century. The cornfields outside Pakrasi’s office window would bloom with photosynthetic antennae, or superefficient solar cells atop flexible structures, their light-consuming faces twisting to follow the path of the sun across the sky. Energy breweries the size of local beer megacorp Anheuser-Busch would be packed with vats full of bubbling blue-green algae that could be used in batteries or other chemical processes. Humanity would survive the fossil-fuel age by drawing energy from cyano. But before Pakrasi’s visions can come to pass, scientists need to figure out how photosynthesis works.

Despite what you may have learned in high school biology, photosynthesis isn’t simple. In fact, it’s a chemical process that follows some seriously weird and mysterious pathways—some of which we still don’t understand. Another Washington University professor, the physicist Cynthia Lo, flipped her laptop open to show me her work on photosynthesis, glanced at some diagrams, and looked momentarily exasperated. “You know why most plants are green?” she asked rhetorically. “It’s because they’re terrible at capturing and absorbing green light. So they capture blue light, but they reflect green. And that’s what you’re seeing in this bright green algae.” Lo is one of Pakrasi’s research collaborators at I-CARES, and the principal investigator on the Photosynthetic Antenna Project. She’s working out the basic science that might one day lead to Pakrasi’s vision of superefficient solar cells collecting light to power the city of St. Louis. Lo clicked through some diagrams of how photosynthesis works at the atomic level, photons colliding with molecules called pigments to produce energy.

Then Lo returned to a theme that would come up a lot in our conversation: cyano are actually terrible at reaping the benefits of photosynthesis. Not only are they missing out on green light, but they only convert about 3 percent of the light they harvest into energy. By comparison, commercially available solar cells convert about 10 to 20 percent of incoming light into electricity. But, Lo said, today’s solar cells can only harvest a small percentage of the light wavelengths that cyano collect—so the bacteria are still way ahead of us in that department. But not for long, if Lo and her lab have anything to say about it.

Lo’s research into the physics behind light capture could help engineers build solar cells that replicate the molecular smashup we see during photosynthesis. Engineers call this biomimesis, or the practice of imitating biological forms to make artificial systems work as efficiently as living systems do—or more efficiently. “A biological system is intriguing because nature has optimized it,” Lo explained. But it’s not optimized enough. Algae harvests light really efficiently, but doesn’t convert it into energy efficiently. Solar cells are efficient at making energy but not at light harvesting. Ultimately, Lo’s goal is to figure out what it would take to develop what she calls a biohybrid solar cell that combines the light-capturing abilities of cyano with the energy-conversion abilities of existing solar-energy technology.

By trying to copy the energy reactors inside each cyano cell, Lo and her team are learning the best possible lesson they can from this mega survivor. They are trying to diversify our energy supply, creating new ways for us to gain energy from the environment so that we can survive long-term with a sustainable electrical grid. It may be decades before we crack the code on photosynthesis, but this ancient organism could guarantee a better future for the planet—just the way it did billions of years ago.

Turning Coal Plants into Cyano Breweries

Another of Pakrasi’s collaborators is working on a strategy to take us from a world run by coal to one powered by plants. Environmental engineer Richard Axelbaum, a wiry man whose office desk is decorated with angular chunks of coal, is interested in the near future of alternative energy. Pakrasi and Lo are looking perhaps half a century ahead, while Axelbaum looks just 10 to 20 years out. He has to be a pragmatist. That’s why he works on “cleaner coal” technology and carbon sequestration, the practice of sustainably disposing of coal’s greenhouse gas by-products.

One of his projects is a prototype coal-combustion facility called the Advanced Coal and Energy Research Facility, located in a huge, high-ceilinged warehouse on the Washington University campus. The facility sustains tanks of healthy algae using a by-product of coal processing. From a viewing gallery two floors above, Axelbaum showed me a tangle of thick pipes, cylindrical tanks, and a grid of shelves packed full of bubbling aquariums. Axelbaum pointed to a tank that looks like an outsized metal barrel turned on its side. “That’s the coal-combustion chamber,” he explained. Unlike typical coal-burning plants, this chamber burns the coal in a pure oxygen environment. As a result, the only by-products of the process are “cleaner” because they’re composed almost entirely of carbon dioxide and ash, with no nitrogen compounds mixed in. “Every generation has had its clean coal,” Axelbaum remarked. Early twentieth-century facilities improved on the extremely dirty coal-burning practices of the nineteenth century, for example. And now he’s hoping that we can improve the process even more, bringing us one step closer to truly clean energy.

Axelbaum’s finger followed a thick duct emerging from the combustion chamber. “That goes to a white-ash capture chamber,” he said, identifying a big, rectangular bin. Normally, coal ash is stored in large open-air ponds, which can cause environmental damage. “Our hope is that all this ash can be put to use, whether in concrete or new kinds of conductive materials,” Axelbaum said. As for the carbon dioxide? “That’s going over to the algae tanks.” Axelbaum pointed at pipes leading to the aquariums. The algae absorb the carbon, thriving on the gas. Axelbaum’s oxy-coal combustion could be feeding (literally) the next generation of superclean energy production.

The Algae Economy

A couple of years before I visited Pakrasi, his team made an incredible breakthrough. They were working with a mutant strain of cyano that releases hydrogen instead of oxygen during photosynthesis, and they managed to coax the algae to produce ten times more hydrogen than other strains had. Hydrogen is often called a clean fuel because when it’s burned it releases mostly water. Hydrogen fuel has been used for rockets, but its production is too expensive for consumer markets. Still, its widespread use in every home is part of the future of cyano-powered energy that Pakrasi, Lo, and Axelbaum dream about.

Imagine a world where brewers grow hydrogen fuel by feeding cyano with the carbon dioxide released from burning coal. The Pakrasi lab’s cyano also consumes glycogen, a by-product of biodiesel production. So basically, these algae cells are eating two harmful by-products of energy production to produce a form of fuel whose consumption releases almost no toxins at all. “They give you a lot of bang for your buck,” Pakrasi said with a laugh. Eventually, we could wean ourselves off coal and make the leap into a cyano-powered world full of new kinds of green fuel.

Pakrasi imagines a future where biologists could even develop specific strains of cyano to transform all aspects of industrial production. The bacteria could eventually replace petroleum, and aid in the production of chemicals like polypropylene, which is used in the synthesis of everything from rope and lab equipment to thermal underwear and durable plastic-food containers. Famed scientist and U.S. secretary of energy Steven Chu has talked about replacing the oil economy with a biofuel “glucose economy.” But Pakrasi and his colleagues in I-CARES have refined this notion even further, and speculate about a global algae economy whose engines run on photosynthesis.

Pakrasi, who studied physics in India before coming to the States for his Ph.D. in biology, says he often looks to India and China for inspiration when he thinks about how to implement the discoveries he’s making in the lab. “It’s hard to [test new energy systems] here or in Europe because these countries have stable infrastructures that are already built. We’re always trying to catch up, to retrofit,” he mused. “But in China or India, it seems like every millisecond they are setting up new structures. These are the places where the technology we’re developing here can be applied directly.” Under Pakrasi’s guidance, I-CARES has developed strong relationships with universities in India and China, and researchers in St. Louis collaborate with colleagues across the world. They’re even reaching out beyond the sciences, to bring in experts in ethics and sociology. “As scientists, we’re good at coming up with technical solutions,” Pakrasi said, “but as far as the policy and human angles, we have to collaborate with [other branches of the university too.]”

I-CARES is the kind of institution that we’ll be seeing more often at universities and in industry, combining people from many disciplines to come up with global solutions to problems that straddle the line between science and society. Already, the U.S. Department of Energy has funded a massive effort in California, the Joint Center for Artificial Photosynthesis, whose aims are similar to I-CARES. Its team of over a hundred scientists, many based at Caltech and the Lawrence Berkeley National Laboratory, aims to develop a way to extract clean energy from sunlight, water, and carbon, just the way plants do.

This futuristic collaborative research could one day save the world. And it grew out of the simple cyanobacteria and its best lesson, which is to adapt and diversify by taking advantage of a sustainable form of energy. In the next chapter, we’ll learn about another life-form with an extraordinary survival mechanism—one that may have helped bring it back from the brink of extinction. You might say that this animal, the gray whale, lives by memory alone.

GRAY WHALES JUST look like survivors. Their slate-colored skin is crusted with barnacles, and their huge, scarred jaws curve downward in what seem to be permanent grimaces. Bottom-feeders who mostly eat tiny crustaceans, these creatures nevertheless have a reputation as formidable fighters. Only packs of orcas and humans usually dare to hunt them, and accounts going back several centuries describe the deadly wrath of grays pursued by whalers. In 1874, the whaler and naturalist Charles Melville Scammon wrote about his experiences hunting grays. He recalled, “Hardly a day passes but there is upsetting or staving of boats, the crews receiving bruises, cuts, and, in many instances, having limbs broken; and repeated accidents have happened in which men have been instantly killed, or received mortal injury.” Grays, he explained, possessed “unusual sagacity,” which made them a hard target—especially when the animals’ intelligence was coupled with their 35-to-50-foot lengths, 80,000-pound bodies, and “quick and deviating movements.”

Despite their ferocity, grays have one vulnerability. Every winter, they migrate thousands of kilometers from the safety of their Arctic Ocean feeding grounds to a series of warm lagoons in Baja California, Mexico. One of the most popular spots is nicknamed Scammon’s Lagoon, after the whaler. Theirs is close to the longest migration taken by any animal on the planet, and the whales will encounter many predators and treacherous conditions along the way. Then, after a winter spent having children (and making them) in the lagoons, they begin the trip back up the coast again, often tailed by their young. Though both the Arctic Ocean and Mexican lagoons are relatively sheltered from predators by natural barriers, the long migrations in between leave the whales exposed to danger for months at a time. How do they manage?

Grays have evolved a number of features that seem to protect them during their migrations. Remarkably, the whales never stop swimming during these journeys. Their brains “sleep” by shutting down only one hemisphere at a time, so one part of the gray’s brain is always awake to keep it moving in the right direction. Even more unbelievably, grays rarely pause to feed during their migration. Instead they live on stored energy. They’ve spent the entire summer grazing on the Arctic seafloor, building up a thick layer of energy-storing blubber which they burn through during the roughly seven-month round-trip to Mexico. Grays eat by taking giant bites of dirt and sifting tasty crustaceans out through the baleen filters in their mouths. This is why they’re often seen with big, muddy smears on their lips after they eat. Marine biologists often jokingly call them the cows of the sea. Grays spend half the year eating so that they can spend the other half migrating and reproducing.

It’s likely that grays have been living this way for the many millennia since they first evolved 2.5 million years ago. Grays are also slightly less complex than some other cetaceans, which has led some biologists to speculate that they are a more ancient species. They don’t “sing” by creating complex harmonies like humpback whales do. They emit what scientists call moaning noises that can be heard only at close range—unlike humpback songs, which can be heard for kilometers underwater. Though grays are able learners, as Scammon observed over a century ago, they don’t exhibit a lot of social behavior like their cetacean cousins the dolphins. Instead of swimming in pods, they prefer to migrate in loose, ever-changing groups of two or three. Many travel alone. Still, grays have maintained what could be called a tradition, their great migration, that gets passed from one generation to the next. This isn’t a matter of mere instinct. Scientists believe it’s something that each new generation of juveniles must learn from the adults, like passing along a map that is vital to the survival of the species. It’s therefore no exaggeration to say that grays survive by relying on their memories. Without memory, they would never find food, nor enjoy a mating season.

Humans nearly drove gray whales to extinction in the early twentieth century, but thanks to one of the earliest conservation agreements in the world, the gray population today has rebounded to what it may have been before whalers thinned the animals’ ranks. The story of gray whale survival offers us two lessons. It teaches us the importance of passing along knowledge from one generation to the next, and it shows us one sure way to stop extinction in its tracks.

Migrations and Memory

People have been observing gray whales for centuries, but there are still many aspects of these creatures’ lives that remain a mystery. Often, we only catch glimpses of their behavior when the whales are in trouble, straying from their usual paths. This was certainly the case in 1988, when an Inuit whaler spotted a group of three grays stranded in the Arctic waters. It was so late in the season that ice had blocked their path out to the northern Pacific. Grays begin their southern migration when the Arctic starts to freeze. If they stay to graze a little too long, they get boxed in by ice that’s formed over the top of the ocean. With no room for the animals to surface and breathe, the straggler grays drown. It happens to a few whales every year, and locals are used to seeing their bodies wash ashore after the ice retreats in summer. But these grays hadn’t drowned yet—in fact, all three (including a small calf) were surfacing to breathe out of a small open hole in the ice. Footage of their struggle to survive captured national attention, bringing television crews and scientists flocking to the small Alaska town where the creatures were stranded.

A young biologist named Jim Harvey came too, trying to reconcile the behavior of these grays with what he’d seen before. These three were clearly working together to share the airhole and survive, though typically grays are solitary creatures. What’s more, the grays seemed to figure out that the humans jumping up and down on the ice around their hole wanted to help them. Eventually, after forces from both the Soviet Union and the United States got involved in the quest to free the whales, the grays followed an icebreaker out to the open sea. Harvey, now a professor at Moss Landing Marine Laboratories (MLML) on Monterey Bay, has spent the decades since the incident studying marine mammals and other creatures that make a home on the shoreline.

When I visited Harvey at MLML, a cluster of artfully designed, recycled wood buildings built just a few yards from the waters of the bay, the door and windows in his office were thrown open. Outside, seabirds skimmed over the sunny water, and grass furred the sand dunes. Further out to sea, sea lions barked and frolicked in waters where the grays travel twice a year. For decades, Monterey Bay has been a prime spot for gray whale observation—it seems to be a favorite place for the whales. Here they swim very close to shore, making it easy to take population counts and watch them in the wild.

From decades of observation, it’s become clear that the whales don’t choose just one group of companions for the whole migration. “They’ll be with a bunch of animals, forming and changing groups all the time,” Harvey told me. “It’s like being in a bicycle race. You can draft behind [the leader], and it’s nice to be in a group because the guy in front is usually paying attention. I think gray whales do that, too. They trade positions in terms of paying attention.” Harvey had just come in from a run along the water, where he’d followed a narrow trail between MLML, a few other local marine-biology labs, and the undeveloped coastline.

His mind still on the dynamics of racing, Harvey pondered a question that is hotly contested among biologists. How, exactly, do the grays learn to navigate their way along all those thousands of kilometers of coastline? “I’m purely speculating,” he said, “but I think they’re following each other, and somebody else follows them, and they remember it.” When I asked whether they’re communicating directions with sound, too, he shook his head. “I’m sure they don’t talk to each other. They’re just following each other.” Young whales always make the trip with an animal that has gone before.

Still, the trip changes year by year; grays are constantly tweaking their route. Twenty years ago, most of the grays migrated along a path that took them inside the Channel Islands, and closer to the coastal cities of Santa Barbara and Los Angeles. The problem was that they stuck to the shoreline too closely, often following it all the way into the shallow waters where they would become trapped. Grays have had similar problems getting lost in San Francisco Bay and Monterey Bay when they chart their course using what Harvey jokingly referred to as the “keep the shoreline on the left” method. But today, their routes take them outside the Channel Islands, and often outside San Francisco Bay too. “So they’ve figured it out,” Harvey said. They realized that more direct routes away from the coast would be faster and less dangerous, and passed that information on. Grays live for about 50 to 70 years, so these course corrections are taking place within the lifespan of a typical animal.

More recently, Harvey and a National Oceanic and Atmospheric Administration (NOAA) biologist named Wayne Perryman have observed that grays are migrating later in the year, possibly because melting Arctic ice means they have to go farther north to find good grazing grounds. As a result, a faster route south is going to become more desirable to the grays as the years go by—they need to cut corners, as it were. But this longer route is also changing a lot more than their maps to the south. In 2012, observers were surprised to find a female gray and her very young calf swimming in San Francisco Bay. Given the age of the calf, Harvey and Perryman estimated that the gray had probably given birth en route to Mexico. She’d left the Arctic so late in the season that she wasn’t able to get there in time to have her baby. It’s possible that the melting Arctic ice will dramatically change the migratory cycles of the Pacific grays, altering the map that one generation of whales passes along to the next. This is another clue that the grays navigate their migratory routes by learning and memory—if the trip were somehow hardwired into their brains, they wouldn’t be able to shift its parameters every year depending on environmental conditions.

Of course, some grays don’t manage to remember the route quite right—which is why, for example, those three grays got caught in the frozen Arctic in 1988 and had to be rescued by icebreakers. This leads Harvey to another big question. Why should the grays continue to migrate at all, as the thawing Arctic slowly becomes more habitable year-round? “It might get to a point when they don’t have to go, but the reality is that the water is still cold,” he mused. And staying warm in winter Arctic waters takes a lot of energy. He and his colleagues believe it’s worth it for the whales to swim all the way down to Mexico and save energy in the warm water, rather than not swimming but remaining in the cold water.

This also helps to explain why juvenile whales make the journey down to Mexico, even though they are still too young to participate in the mating and calving that goes on in the lagoons. To get the most out of all the blubber they’ve been building up in summer, the young whales need to seek out warmer waters with their elders. But there’s another benefit, too. “Eventually, if you want to be part of the reproductive group, you need to know how to do the migration,” Harvey explained. “They are gaining knowledge, including reproductive knowledge, by making the journey.” It’s likely that the young whales are learning another survival skill along with the route south and then north again. When they arrive in Mexico they’re watching other grays reproduce. How whales learn to mate is a big question mark scientifically, but Harvey said it’s possible that they do it the same way they learn to migrate: through observation and memory.

How the Gray Whale Came Back from Extinction

Unfortunately, memory is no defense against the concerted efforts of ships full of people with harpoons and explosives. The descendants of the whales Scammon hunted still roam the waters of the Pacific coast, but their now-extinct relatives in the Atlantic weren’t as lucky. A large group of grays lived in the Atlantic for thousands of years, migrating from the Arctic to the Mediterranean. But historical evidence suggests that they succumbed to hunters in the eighteenth century. Today, there are only two groups of gray whales left. One, the eastern Pacific, or California-Chukchi group, whose migration we’ve talked about up to this point, contains perhaps 20,000–30,000 individuals. The other is a small, poorly understood group of roughly 200 individuals called the western Pacific or Korean-Okhotsk grays. These whales have a different migration route, along the coast of Asia. In summer they graze along coastlines in the Sea of Okhotsk off the coast of Russia, above Korea and Japan. Their calving grounds are off the coast of Korea.

Both these groups would have gone the way of their Atlantic cousins if it hadn’t been for the rise of conservation groups in California during the early twentieth century. After the establishment of groups like the Sierra Club, which helped protect Yosemite National Park from development in the late nineteenth century, the burgeoning environmentalist movement began to think about protecting animals as well as environments. Even whalers like Scammon noted with unhappiness that the whales were going to be exterminated if hunting kept up at the pace he observed. Often, hunters would simply plow into the mating lagoons and slaughter the vulnerable mothers and calves, destroying the population’s ability to reproduce. Disturbed by the inhumanity of these hunting practices, and aware that grays weren’t particularly valuable as commodities, in 1949 the newly formed International Whaling Commission outlawed the hunting of gray whales. Since that time, many scientists believe that the eastern Pacific population has bounced back to what it might have been before whaling started. Others argue, based on genetic data, that it’s likely the original population before whaling was closer to 90,000 individuals.

Regardless of what the original population was, marine biologists who study the whales seem to agree that the California grays have rebounded in an extraordinary fashion. Over the past 60 years, they’ve gone from near extinction to a healthy, diverse group capable of learning new migratory strategies to cope with changing conditions in the Arctic. Their growing population numbers stand in stark contrast to those of other whales, especially ones like the right whale, humpback, and blue whale that navigate their own great migrations every year. Several studies suggest that noise pollution in the water from radar, and human encroachment into their territories, may be disorienting these whales. This leaves them vulnerable to beaching, or injuring themselves by swimming straight into large ships.

Grays were saved from extinction because humans chose to change their behavior. It’s possible that humans might save other whales from extinction, too, by changing our behavior in the same way. We could avoid using frequencies that whales prefer for their sonar. Or we could track whale migratory patterns using satellites—something that many scientists do already—and avoid creating shipping lanes near the areas where whales are making their journeys. Changing the way we use sonar is obviously more difficult than outlawing whale hunting. But it is certainly possible, and today’s gray whale population is a reminder that extinction is not inevitable for these massive sea mammals.

There’s another reason grays are good survivors, though. Their migratory patterns keep them relatively safe and well fed. Few animals compete with them for food in their Arctic Ocean hunting grounds, which are vast and well stocked. Humpbacks, by contrast, feed in a small coastal area, which Harvey calls “a very compressed region.” If they can’t find prey in that region, humpbacks suffer. But the grays have found an enormous feeding ground where they can chomp on the seafloor during summer, as well as a protected place to mate in winter. And they’ve carefully charted a route between the two places that’s as safe as possible. Traveling along the coasts, their large bodies are generally hidden from predators by the sounds of the surf and the dirty, silty water they love. Their lack of sonar may mean that grays are more solitary, simple creatures than some other cetaceans. But this simplicity has helped them rebound from extinction, while whales with more complex communication and social structures are suffering.

Still, the grays would never have made it this far without their ability to pass along a survival map from one generation to the next. As long as they keep learning new ways to survive the arduous Pacific coastal migration, the grays will endure.

Always Coming Home

Nomadic humans survived for thousands of years in a similar way, wandering across vast regions to find food and good seasonal weather. Many human tribal groups had traditions where they met once or twice each year for large gatherings, not unlike what the grays do when they converge in the Mexican lagoons. At these gatherings, nomadic humans would exchange gifts, pass on stories, and find people to marry outside their bands. Today, however, human survival can’t hinge on migratory patterns. Most humans live in settled communities and cities, and the knowledge we pass on to the next generation is infinitely more complex than a migratory route or information about where to find the most abundant food. We’ve learned so much that we need libraries and databases to augment our memories.

Still, the grays have a lesson to teach us about the role of memory in survival. This struck me forcefully one afternoon in Monterey Bay, when I joined a whale-watching group in a small boat that fought its way over wind-whipped waves in search of the elusive migrating grays. The most adventurous of us made our way to the bow with our cameras, clinging to the railings and getting completely soaked by spray. We were joined by several large schools of porpoises. A group of four kept jumping out of the waves at the same time in graceful synchrony, as if trying to make it clear to the ridiculous monkeys who really belonged out here. But we kept scanning the horizon for grays, hoping to see their characteristic spouts. At last, just when we were about to retreat, we spotted one. The whale slid its blowhole just above the waves, most of its great bulk obscured by water and distance, and disappeared again. We all jumped up and down, pointing and forgetting to take pictures in our excitement. Just the sight of such a magnificent creature filled us with crazy awe, and all the sopping people in the bow started bonding and swapping stories of other amazing animals we’d seen. One person had seen a Bengal tiger in the wild, and another had been in Mexico to see the grays in their winter home. Nobody forgets these kinds of sightings because most of us, no matter how much we love urban life and civilization, also deeply love nature.

Like grays, humans are good survivors because we’ve learned to find food and homes across a vast region of the planet. Also like grays, we’ve learned to traverse these territories in more efficient ways, responding to changes in the environment. We’ve figured out how to build cities that protect us better than villages did; we’ve passed along stories of how to survive best on what is still a dangerous planet. Sometimes, we’ve even changed our behavior to protect life-forms other than ourselves. As we turn to the next part of this book, about planning for the future, we’re going to remember the grays’ lesson: You’re always coming home, but the path to get there is going to change all the time.

IN THE PREVIOUS three chapters, we’ve zeroed in on strategies that have helped three different life-forms—humans, cyanobacteria, and gray whales—survive in extremely adverse conditions. We learned how an ancient tribe of humans, today called Jews, lived by scattering and founding new communities in the face of war and oppression. We explored how cyanobacteria’s ability to generate its own form of sustainable energy has made it perhaps the most adaptable life-form on Earth. And we followed a group of gray whales on their difficult migration down the eastern Pacific coast, a journey each whale has memorized in order to survive, and even to bounce back from extinction once humans agreed to stop hunting them. By passing along stories about these survivors, we learn what it would take for humans to survive, too. But some stories about survival are more helpful than others.

In part two, we explored the role symbolic communication played in human evolution. Storytelling could be called the cultural backbone of human survival. There’s a reason that conquering armies often burn the books and libraries of their enemies. Extinguishing a people’s stories is a way of erasing their future. But when we remember those stories, they can steer us in a direction that leads away from death. In fact, stories about how humans might live in the future—sometimes known as science fiction—may be among the most important survival tools we have. We can use these stories as a highly symbolic version of the migration maps that gray whales pass on to the next generation. Futuristic stories offer possible pathways our species can take if we want our progeny to thrive for at least another million years.

What Makes Us Want to Survive?

One of the twentieth century’s greatest science-fiction writers, Octavia Butler, told Essence magazine, “To try to foretell the future without studying history is like trying to learn to read without bothering to learn the alphabet.” Butler grew up during the height of the space race in the 1950s, surrounded by hopeful stories about how humans would colonize the Moon, Mars, and beyond. But her life as the intensely shy daughter of a maid wasn’t exactly Forbidden Planet material. Butler’s mother was a widow who had no home of her own—instead, she and Butler lived in the home of her employers, a white family where Butler recalled visitors making casually racist remarks as if she and her mother weren’t in the room. As an adult, Butler always expressed great admiration for her mother’s tireless efforts to survive, to keep going, despite the many barriers in her way.

Perhaps for this reason, Butler’s great gift as a writer was her ability to tell moving, realistic stories about how people would survive in futures far more harrowing and strange than anything that ever appeared on the Enterprise’s sensors in Star Trek. Still, she often joked that bad science fiction inspired the themes in her writing as much as growing up black in a white-dominated world. She penned her first short story after watching Devil Girl from Mars on TV late one night, and realizing that she could do better.

The literary world would never put Butler’s work in a class with Devil Girl. Not only did she win many SF literary awards before her death, in 2006, including the Hugo and the Nebula, but she was the first SF author ever to win the MacArthur “genius grant” usually bestowed on fine artists and distinguished scientists. Ultimately, what makes Butler’s work mesmerizing is her incredible ability to help readers see the world from a perspective radically different from their own. In an essay for O, The Oprah Magazine, Butler recalled a formative experience. She visited a zoo with her elementary school class, and watched in horror as the other kids threw peanuts at a caged chimp, taunting him. As the animal wailed in frustration (and possibly madness), the young Butler realized she had more sympathy for this ape at that moment than she did for her fellow humans. She’d caught her first glimpse of humanity as it might look through alien eyes, and the experience left its mark on her imagination forever. “At age 7, I learned to hate solid, physical cages—cages with real bars like the ones that made the chimp’s world tiny, vulnerable and barren,” she wrote. “Later I learned to hate the metaphorical cages that people try to use to avoid getting to know one another—cages of race, gender or class.”

Many of Butler’s novels can be understood as thought experiments in which she offers solutions to the problem posed by that group of children tormenting the chimp. At the heart of this problem are those metaphorical cages. Such cages can be more pernicious than steel bars, because they prevent humans from seeing what we have in common as members of a species in danger of going extinct. How can humans survive in the long term when we seem to be so good at building cages? What would it take to alter the course of humanity?

These are the same questions that I’m asking in this book. We can only meet the challenges of surviving whatever the natural world throws at us by working together as a species in small and large ways. Before we understand the nuts and bolts of survival strategies, however, it’s important to take a short philosophical break and think about why we’re doing this in the first place. Why do we want to survive? What is it that makes life worth saving? How do we hope to improve humanity over the next million years, and what would that look like?

Using a few of Butler’s science-fiction novels, we can think about some possible answers to these questions.

Surviving Is Always a Compromise

Most of us want humanity to survive for a simple reason: We hope there’s a chance for our families and civilizations to endure and improve over the long term. The problem is that we have a hard time imagining what that would look like. We envision a far-future world full of people who look just like us, zinging around the galaxy in ships that are basically advanced versions of rockets. And yet, if history is any guide, the humans of tomorrow will be nothing like us—their bodies will have been transformed by evolution, and their civilizations by the kinds of culture-changing events that have already marked human history. In her trilogy of novels called Lilith’s Brood, Butler dramatizes why some people choose death over survival. They are not prepared to deal with the radical changes required to bounce back from extinction. Still, Butler’s story offers us hope for humanity’s survival, and a new way of thinking about how we’ll do it.

When Lilith’s Brood opens, a civilization of bizarre, tentacle-covered aliens called the Oankali have just kidnapped the tattered remnants of humanity after a nuclear apocalypse. Unlike humans, who evolved to use machine technology, the Oankali’s entire civilization is based on biology. They journey through the galaxy in living spaceships the size of planets, and every part of their environment—from their tree homes to their sluglike cars—is alive. They’re an ancient species who have dealt with many alien cultures, and they view humans as a fascinating anomaly: We’re intelligent creatures who live hierarchically. Apparently this is an incredibly rare combination in the universe, and they suspect it’s what led to our downfall. Luckily, as a representative of the Oankali explains to the protagonist, Lilith, they’ve preserved the few remaining humans in stasis pods while the Earth returns to a healthy state of nature.

Though seemingly benevolent, the Oankali do want something in return for rescuing the remaining humans. They awaken Lilith before all the other people to offer a bargain: They’ll grant humans a rich, disease-free life if they agree to have children with the Oankali. It turns out that the Oankali evolve as a species by merging their DNA with other species, creating an entirely new kind of life every few generations. As the Oankali’s reluctant ambassador, Lilith must explain the deal to her newly awakened fellows and get their consent. Some of the humans are more willing than others, but all of them are suspicious of Lilith’s position—they see her as compromised because the Oankali have already reengineered her to be stronger and more intelligent than an ordinary human. Her capabilities are just a taste of what her half-Oankali children will have. But are the Oankali making the humans better, or robbing them of their humanity? Are they asking the humans to join them as equals, or to become their breeding stock?

One group of humans rebels against the Oankali, refusing to join them and opting to face death rather than form families with creatures they see as hideous oppressors. Lilith, meanwhile, consents to the deal. She and her lover, Joseph, form a typical Oankali family, which consists of a male, a female, and a third sex known as the ooloi. The ooloi can combine genetic material in its body and create mixed-species offspring which would never be possible via the kind of sexual reproduction humans are used to. Though Lilith comes to love her ooloi Nikanj, and her hybrid children, she is plagued by doubts. Maybe the separatist humans are right to refuse the bargain. Maybe the Oankali have pushed her toward accepting them by controlling her neurochemistry, slowly robbing her of the desire to resist assimilation. There’s also the nagging question of whether she’s truly surviving at all, if her children will no longer be properly human.

As the series goes on, these questions become even more thorny. We discover that the Oankali plan for their hybrid children to travel the universe in a living ship whose body will grow by consuming the entire Earth. Though the Oankali have, after long argument, given the separatist humans a refuge on the rejuvenated planet, this is only temporary. The unassimilated humans will die as the ship comes to life.

In some ways, the Oankali are giving humans what we’ve always wanted: perfect health, long lives, plenty of food, and a perfectly peaceful existence. But their bargain begins to sound a lot like what Europeans offered natives when they arrived on American shores in the wake of the great pandemics that were decimating their populations. In exchange for a few valuable commodities like guns and wool, Europeans disrupted the natives’ cultures and completely transformed the lands where they lived. The longer the natives lived among Europeans, the less they seemed like Apache or Inca, and the more they seemed like hybrid peoples with one foot in their parents’ cultures and one foot in their colonizers’. Even though Lilith and her children will survive, humanity as we knew it will not.

The thread that runs through Lilith’s Brood is the idea that human survival involves radical transformation. At the same time, Butler offers us reassurance that though our bodies may change and our cultures fall under alien influence, we will retain our humanity. As Lilith’s children come of age, we begin to see the world from their perspectives as creatures who are part of a species that never existed before. Though they are half Oankali, they treasure their human sides, too. Indeed, the first human-Oankali hybrid ooloi winds up falling in love with a man and a woman from a separatist human community, and discovers in the process what makes humanity so valuable. Unlike other species the Oankali have assimilated, only the humans have put up organized resistance to assimilation. As a result, the Oankali realize that they have to change their way of life. They will no longer assimilate whole species, but instead leave part of each species behind to continue on its own path. You might say that humans inject pluralism into the Oankali culture. And the Oankali, for their part, give humans a peaceful future among the stars.

So how can such an outlandish story shed light on our future as a species?

The strength of Lilith’s Brood as a thought experiment lies in Butler’s suggestion that human survival means an endless and increasingly profound series of compromises. Importantly, the books do not have a tidy, happy ending—far from it. Though the humans survive, both as pure humans and as hybrid Oankali, they endure incredible losses that some might argue are worse than death. To put this in the kind of historical perspective that we began with, the long-term outcome of cultural meetings between Africans and Europeans could hardly be described as unambiguously good, even though slavery was eventually abolished. We cannot ever hope to reach a future where the scars of history completely vanish, nor can we expect that we won’t be wounded again in the future. The key is to understand those injuries in the context of a much longer story about the great transformation known as survival. Hopefully, the rewards of seeing our half-alien children building an improved world can offset the injuries that produced them. This is why we survive, Butler suggests. We want to witness the birth of something better.

In Lilith’s Brood, Butler resists offering a pat definition of what “something better” might be. Certainly it seems that the human-Oankali way of life will be healthier, more sustainable, and more peaceful than ours is today. The author also hints that it will involve preserving what’s best about humanity: our ability to change while remaining true to what came before us. Perhaps most important, “becoming better” doesn’t mean transcendence. Though her future humans are vastly more powerful than us, they don’t achieve a state of perfection. They are the hybrid result of compromise—better than we are, but still dealing with conflict and disappointment.

One of the great lessons about future survival that we can take away from Lilith’s Brood is that it will require us to change. And those changes may be a lot more difficult, and a lot weirder, than we expect.

“God Is Change”

It’s easy to say that we need to change to survive, but how do you get people to risk everything to do it? How do we unite people divided by those symbolic cages and work on a long-term goal together? That’s a question Butler tackles head-on in two of her most realistic novels, Parable of the Sower and its sequel, Parable of the Talents, both set in a near-future United States that has been torn apart by poverty, climate change, and political instability.

We begin with Los Angeles burning down. In Parable of the Sower, we find ourselves in one of the last remaining gated communities outside L.A., where gangs have breached the walls and are setting houses on fire. A teenager named Lauren Olamina heeds what her father taught her on the shooting range, grabs her gun and emergency backpack, and flees into the burning night to find a safe road up to Northern California. She’s heard things are better up there. Along the way, though, she and her traveling companions are kidnapped by a militia and tortured in reeducation camps. After months of beatings, they’re released when the U.S. government begins to take power back from the separatists and gang leaders who have claimed the land.

During her ordeal, Lauren solidifies a plan she’s had since childhood. She will create a new religion. It will be a system of beliefs that she hopes can bring people together in empathy, preventing anyone else from ever having to endure what she did. She uses the word “God” in her teachings, but not the way most Americans would. First of all, God isn’t a white guy with flowing hair, floating in the clouds. God is an abstraction, described only as “change.” Lauren invokes this God to aid people who are suffering, but she also claims her God is devoted to shepherding the children of Earth into space, where they will scatter joyfully to the stars. Looked at from one perspective, Butler is drawing from the Judeo-Christian God, whose idea of justice in the Bible helped African-Americans protest slavery and inequality in the United States. But looked at from another perspective, this abstract God of change reflects the idea of evolution in action. Either way, Lauren’s God is a powerful idea, one that her characters in postapocalyptic America use to survive an ordeal that nearly destroys humanity.

In Locus magazine, Butler explained:

The Parable novels are, in essence, a story about reconciling religion with social change, God with science, and the past with the future. In these books, Butler makes explicit what is only hinted at in Lilith’s Brood: Humanity’s story must be one of constant change because that is one way to transmute pain into hope. Lauren’s goal for humanity, and, indeed, the goal of the book that you are reading, is to get us off this crowded planet and into space. There, we can continue to change and hopefully, through exploration, learn more about how to build a civilization that doesn’t lock its members into various cages that prevent us from seeing our common goals.

But, as Butler told a student attending one of her lectures, “There’s no single answer that will solve all our future problems. There’s no magic bullet. Instead there are thousands of answers—at least. You can be one of them if you choose to be.” First, however, you must be brave enough to turn away from death, embrace change, and survive.

In the next two parts of this book, we’ll explore two ways humanity will need to transform in order to survive as a species, with our histories and traditions intact, but changed enough to make our future civilizations sustainable ones. We’ll begin by transforming the cities where so many of us live and work. And, ultimately, we’ll start building those cities beyond this dangerous, explosive planet we call Earth. We’ll scatter to the stars, changing ourselves in order to survive, but always remembering home.