The Natufian Threshold and the Younger Dryas

For nearly the whole of the human story so far, across every single chapter you have read, our ancestors lived in one basic way: in small mobile bands, hunting and gathering, owning little, moving with the seasons and the herds and the ripening of wild plants. It is easy to pity that life from the comfort of a heated room with a full refrigerator, but we should be careful before we do, because the anthropology suggests we would be pitying the wrong people. These were often not desperate creatures scraping at the edge of starvation but well-fed, deeply skilled, widely knowledgeable, and, by the reckoning of researchers who have studied surviving forager societies, blessed with a great deal more leisure than the farmers who would replace them. For something like ninety-five percent of the entire existence of our species, this mobile, propertyless, comparatively egalitarian life simply was human normal. What we are about to watch, in the last few thousand years before civilization, is the ending of that immensely long way of being, and, revealingly, it did not begin with farming. It began with something quieter and stranger: with people choosing to stop moving.

As the last Ice Age finally began to loosen its grip, in a green and well-watered corridor of the Near East, a people we call the Natufians did a quietly revolutionary thing. Without yet farming at all, they settled down. The wild cereals on the hillsides and the game in the valleys were abundant enough that they could build round stone houses, live in one place the year around, grind and store the wild grain, and bury their dead beneath the floors of their homes. This is the crucial and counterintuitive fact, and it overturns the tidy sequence most of us were taught: sedentism, staying put, the great precondition for everything that follows, came before agriculture, not after it. People chose to stop wandering while they were still hunter-gatherers, and in that single choice the entire shape of the human future was already quietly bending toward the granary and the city.

And then the sky went cold. Around twelve thousand nine hundred years ago, in the very middle of the warming that was supposed to be ending the Ice Age for good, the climate of the northern world lurched violently and without warning back into deep cold, and stayed there for more than a thousand years. This is the Younger Dryas, named for a little Arctic flower whose pollen came flooding back into European sediments as the tundra returned, and it is one of the sharpest climate reversals in the entire geological record: temperatures in Greenland plunged by as much as seven to ten degrees, the onset possibly compressed into a single human decade, a near-glacial millennium dropped like a stone into the middle of the thaw. The mainstream explanation is dramatic enough on its own: a colossal pulse of meltwater from the collapsing ice sheets is thought to have flooded into the North Atlantic and choked off the great ocean current that ferries tropical warmth northward, throwing the whole hemisphere back into winter. A bolder and far more contested idea holds that a fragmenting comet struck or air-burst over the northern ice, and here, precisely here, the book's discipline earns its keep, because this is exactly the kind of claim that gets sensationalized in one direction and sneered at in the other. There is a scatter of genuinely intriguing evidence offered for an impact: a dark "black mat" layer draped over the boundary at many sites, microscopic diamonds, spikes of rare metals like platinum. And there is a serious body of scientists who examine that same evidence and find it unpersuasive, contaminated, or explicable by ordinary means. So we will say exactly what is true and no more. The cooling itself is beyond any dispute. Its cause is genuinely unsettled, an open and active scientific argument, and anyone who tells you flatly that the comet impact is proven, or that it has been finally refuted, is claiming considerably more than the evidence can currently bear.

What the Younger Dryas did to the newly settled people of the Near East is not, however, in dispute: it made their comfortable sedentary life suddenly hard. The wild abundance that had let them stay put thinned out as the cold clamped down. And it is precisely in this squeeze, as the returning winter pressed on people who had already committed themselves to staying in one place, that we find the most astonishing site in this whole Part of the book, a place that rewrote the textbooks within a single generation of digging.

On a windswept hilltop in southeastern Turkey called Göbekli Tepe, hunter-gatherers, people with no pottery, no metal, no writing, and no domesticated crops whatsoever, quarried great T-shaped limestone pillars, some of them five and a half meters tall and weighing as much as sixteen tonnes, carved them in relief with foxes and boars and cranes and scorpions and, more often than any other creature, serpents, and arranged them standing in deliberate rings. And they did this beginning around eleven and a half thousand years ago, centuries before the first domesticated wheat appears anywhere. For most of a century, the story of civilization had been told in one fixed order: first people learned to farm, then the food surplus freed a few of them to build temples and imagine gods. Göbekli Tepe turns that story upside down. Here the monument comes first, raised by foragers, and the considered judgment of Klaus Schmidt, the archaeologist who recognized the site's importance in 1994 and dug it until his death, was that this was a sacred gathering place, a ritual center, and that the sheer organized effort of quarrying, moving, carving, and above all feeding the work crews may have been one of the pressures that drove people toward farming, rather than farming's reward. It is a real and still-debated possibility that the temple came before the town, that the gods came before the grain. We will hold the site's wilder readings, the claim that one particular carved pillar secretly encodes the date of a comet impact, for instance, at arm's length, flagged clearly as one researcher's provocative interpretation and not established fact, and we honestly do not need them. The plainly documented, securely radiocarbon-dated truth of Göbekli Tepe, that Stone Age hunter-gatherers built monumental sacred architecture on this scale, is astonishing enough on its own, and it should leave us permanently humbler about how much of the deep human past we have simply assumed we understood. Only some five to ten percent of the site has even been excavated. Then, around ten thousand years ago, for reasons no one understands, its builders deliberately buried the whole thing under tons of rubble, and walked away.

This is the honest place to face a larger temptation head-on, because the body of research this book is built upon brushes right up against it. The drowned coastlines of the melting Ice Age, which really did swallow vast inhabited lowlands, and the genuine sophistication of people like the builders of Göbekli Tepe, have together inspired a seductive idea: that some advanced, technologically capable civilization flourished during the Ice Age and was entirely erased, leaving only the world's flood legends behind as its epitaph. We take the underlying facts with complete seriousness, because they are real and badly underappreciated: as the great ice sheets melted, sea levels rose by roughly a hundred and twenty meters, the height of a forty-story building, whole landscapes where people certainly lived now lie drowned on the continental shelves, and flood memories genuinely do echo across cultures the world over. But we follow the evidence where it actually leads, and the evidence for a lost high civilization, with cities and metallurgy and advanced technology, simply is not there in the ground. What the evidence shows instead is, in its own way, a far better and more surprising story: hunter-gatherers of astonishing skill, organization, and ambition, doing monumental things that no one had believed such people could do. The truth here is more interesting than the fantasy, and it carries the considerable additional advantage of being true.

However it was finally pushed over the threshold, the great change came, and it was the largest single transformation in the entire human story. Across the few thousand years following the Younger Dryas, in the Near East first and then quite independently in China, in the Americas, in the highlands of New Guinea, and elsewhere, people began to plant and to harvest, to pen and to herd, to domesticate the handful of plants and animals that would, in a real sense, domesticate them right back. We call it the Agricultural Revolution, and it is the doorway out of this Part and into the next, but we should walk through it clear-eyed rather than triumphant, because it was emphatically not simple progress. Farming fed more people from the same land, and that was at once its enormous power and its inescapable trap: it grew populations that could never afterward shrink back to the old way, and it did so at a genuinely bitter price. The skeletons tell the story plainly. The early farmers were shorter than the foragers they replaced, and sicker, their teeth rotting on a starchy diet, their bodies worn by repetitive toil, their crowded villages and their livestock breeding the epidemic diseases that had never troubled the mobile bands. And with the storable surplus came something the forager world had largely lacked: the possibility of hoarding, and therefore of some people holding far more than others, and therefore of permanent inequality and the power that grows from it. The forager's world of few possessions and rough equality was ending. The world of granaries and walls and kings was about to begin.

And with it, everything speeds up. We have spent four Parts and the better part of fourteen billion years to arrive here, at a single settled village with a planted field around it. From this point on, the pace of the story changes completely, because now, at last, our ancestors begin to write, and for the first time in the four-and-a-half-billion-year history of the Earth, the past begins to keep its own records, in its own words.

The rock had come alive. The animal had come awake. And now the awakened animal was about to build a world entirely of its own making.