History tells us that civilisations and empires ultimately disappear. Like the Egyptian civilisation, they may last for thousands of years or, like the extensive Mongol Empire, be gone in less than 200 years. The ebb and flow of power and influence even just in Europe and around the Mediterranean in our recorded history would take a very long time to recount.

But what is more puzzling is what happened in the days before the empires of which we have written records. Our recorded history is actually a very small part of our existence as hominids. For almost all of our 300,000 years of human existence, our species has been roaming the planet, living in small groups, hunting and gathering, moving to new areas when the climate was favourable, retreating when it turned nasty. It has though only left indirect evidence of what was happening.

For hundreds of thousands of years, our ancestors used fire to cook and warm themselves. They made tools, shelters, clothing and jewellery. Then, about 10,000 years ago, everything began to change. In a few places, people started growing crops. They spent more time in the same spot. People in places as disparate as Mesopotamia, northern China and South America all turned to farming within a few millennia of each other. They built villages, towns and cities. Various unsung geniuses invented writing, money, the wheel and gunpowder. Within just a few thousand years – the blink of an eye in evolutionary time – cities, empires and factories mushroomed all over the world.

Archaeologists and anthropologists have sought to explain why this rapid and extraordinary transformation occurred. For almost our time as humans – including during the tumult of glaciations – we had been hunters and gatherers. So why did our ancestors abandon a lifestyle that had worked so well for so long?

Anthropologists had pieced together a story to account for such a massive change. The thinking was that people in a few particularly fertile places tried farming because it seemed like a good idea – then found there was no way back. By producing more food, they triggered population growth, forcing them to grow ever more food. Individuals who could control supplies of grain did so, becoming the first rulers and emperors in what had previously been egalitarian societies. To maintain control, they created or harnessed the apparatus of state, like writing, legislation and armies.

Now, growing evidence suggests that this account is a fiction. The first problem is that it misrepresents hunter-gatherer societies. This is illustrated by Göbekli Tepe, located on a hilltop in southern Turkey. Beginning in the mid-1990s, excavations there have revealed a series of circular enclosures each containing T-shaped stone pillars several metres high, some with carvings of animals or other symbols. Surrounding these enclosures are rectangular buildings.

This is not surprising - except that it dates from between 11,500 and 10,000 years ago – before the origin of agriculture. No domesticated plants or domesticated animals have been found there. So hunter-gatherers sometimes created monumental architecture. Why, we don’t know - it wasn’t a living space: there is no source of water and no evidence of permanent fireplaces. And the stone pillars, or megaliths, are too large to have been carried by small groups. There are also stone troughs that were used to process wild cereal grains into porridge and huge quantities of beer. Some of the carved animals there appear to be male and none are female, leading to the suggestion that men gathered there for initiation rites. Since its discovery, megaliths from similar eras have been found at a number of other sites in Europe, South America and Louisiana.

In recent decades, studies of modern hunter-gatherer groups have also contradicted our ideas about their social structures. We normally think of hunter-gatherers as living in small, nomadic bands that are fairly egalitarian and cooperative. But it seems that actually there are quite a few examples of what are called ‘complex hunter-gatherers’. Those are people who remain in one place and have a high degree of social stratification. There can be a hereditary ruling class, for example, where you have chieftainship that is inherited. They have slavery and warfare.

It may be that some hunter-gatherer groups behaved in these ways for tens of thousands of years. There isn’t much direct evidence. But there are burials of people with ornamentation and other items that looked like they might have been of a higher class, perhaps rulers, that are 20,000 or 30,000 years old. Göbekli Tepe itself was deliberately buried for reasons unknown and much of the other evidence has probably rotted away, or itself been hidden.

While many questions remain, one thing is clear: the traditional story – that complex societies began with the development of agriculture is not true. Hunter-gatherers could form large groups, perform rituals and construct elaborate monuments. Farming and its involvement with a specific area wasn’t a prerequisite for this.

The second big source of uncertainty is why people took up farming at all. But early farms were more like gardening than the farms of today. Also, the first farmers weren’t just farming. There was still a lot of gathering, hunting and fishing at the same time.

The obvious reason people might have started farming is that it produced more food, or at least a more predictable supply. In Çatalhöyük in Turkey, a community of farmers lived in a dense village between 7100 and 5600 BC. The research shows that over its 1500 years it ran quite successfully. There are some relatively minor changes in the size of the community, but it had a very diverse cropping system, with five or six cereals, a similar number of pulses and a lot of foraging.

In contrast, in Britain only a few cereals were farmed. The result was a volatile boom-and-bust cycle in which populations grew for a few centuries, but then shrank and dispersed when crops finally failed. Jethro Tull and his agricultural revolution had yet to appear. And so it isn’t obvious that farming always offered nutritional gains.

But it also doesn’t look like a trap. There are quite a few examples of groups who adopted and then abandoned agriculture. Stonehenge and other Neolithic monuments of the British Isles were built by populations who adopted cereal farming from continental Europe, but then abandoned it.

There could have been cultural reasons to farm. The hunter gatherers had already shown what we could interpret as a wish to put down roots with the construction of their megaliths. Indeed we, their descendants, show attachment to place. They were perhaps attached to a part of the landscape and did what was necessary to make it possible to continue to live there. Activities like burials, allowing people to remain near to their dead relatives, are evidence of this.

But the underlying answer or at least the most significant one, may well be quite prosaic: climate change. During the period before about 10,000 years ago – the Pleistocene – temperatures fluctuated a lot over decades and centuries. A nomadic hunting and gathering lifestyle may well have been the best way to find food when conditions were so unpredictable. But it is clear that during our current Holocene epoch, a more predictable climate has allowed farming to thrive and, with it, a life based on staying in the same place.

Humans didn’t start farming and building relatively complex societies just in the Holocene - it seems that it has always been a feature of life - but people couldn’t adopt it permanently and go on to create towns and cities while the climate was too unstable.

Which makes us ask: what will happen when the climate becomes less stable over the next decades? Can we expect a resumption of movement from areas no longer adapted to agrarian living to more temperate zones?

Hunting and gathering is unlikely to make a comeback and obviously these days we have relatively few people actually involved in agrarian activity. But although most of us actually live in large conurbations and make our living in very different ways, all of us depend ultimately upon farming.

As the climate becomes more unstable again, however, there will either be mass movement to more stable areas of the globe or there will need to be technological change such that food can be produced despite the unstable and overheated climate. At the same time, the cityscape will be sorely tested.

How all this will play out is impossible to predict, but massive change is on its way.

3 July 2023

Paul Buckingham