Listen to the Episode:
A woman, not more than twenty years old, steps onto a ramshackle platform: tree trunks and branches, bound together, edging into a lake.
The Sun has just begun to climb above the horizon. As she picks her way over the logs, the woman’s hand grazes a thicket of reeds along the lakeshore. She notices the Sun’s milky light, swirling through wisps of fog, rising off the water.
It’s cold. Bitterly cold, and she shivers beneath her thick hides. When she reaches the end of the platform, rocking gentle in the water, she stops short. To her surprise, a lacquer of ice stretches across the lakeshore from the wood into the mist.
But the leaves have only just started to turn. She can think of no memories, no stories of ice so soon in the year. It disturbs her. She remembers when, last year, the frost came late, after the reeds had grown high.
She fears that something has changed about her world.
But then she hears a familiar splash, off in the distance where the water must be open. And another. Carp, leaping in pursuit of prey – or pike, leaping in pursuit of carp. The spirits of the water endure.
Now she hears the whoosh of wings overhead, glimpses the shadow of a crane, descending. Far away she hears a yipping – the call of a white-fronted goose – then the deep, resonant honk of bean goose, a little closer. The sky is as it was.
She reaches for a stick, and uses it to shatter the thin ice nearest the platform. She crouches, skimming a basket over the water. When she sweeps the basket onto the platform, she grins at the rich black lily seeds inside.
No matter the weather, she decides, the creatures of her home – humans included – will survive as they always have. By growing together, by honoring each other, by giving and taking.
She walks back across the platform. And idly, before she reaches the shore, she kicks a bone into the water.
11,000 years pass. An archaeologist finds that bone. He’s been digging in the muck at a site now called Star Carr. The lake is long gone. The only trace of our twenty-year-old is that bone she kicked without thinking.
But we now know that her people did endure. For centuries, even after the climate cooled and dried. Even when the warming of the Holocene faded for a while.
The remains at Star Carr remind us that humans can survive a change in climate – when they respect the world around them.
Welcome to the thirteenth episode of The Climate Chronicles, the second of our third season, “Into the Holocene.”
Many of our episodes have ranged across huge expanses of both time and space. Some have covered millions of years, and considered the whole planet.
But in this episode, we’re going to focus on a place that seems to have been occupied for part of the year by just one small community. A community that consisted of no more than three families, and at most 20 people.
These people continued to hunt and gather in the early Holocene, staying put in some months, following migrating animals in others. But although their lifeways resembled those of the Pleistocene in important respects, such communities were no less dynamic than the growing agricultural towns of the Levant. They, too, tinkered with emerging technologies to exploit environments in new ways.
And many were relative newcomers to new environments. They’d arrived there after the retreat of glaciers, and the warmer, wetter weather of the Holocene, made it possible.
It was still a precarious world. In the early Holocene, the ice sheets had not yet retreated to where they would be, several thousand years later. Meltwater continued to flow into the Atlantic Ocean – sometimes in sudden bursts.
So, even after the Younger Dryas faded away, the circulation of water in the ocean occasionally slowed down, and the climate of the Northern Hemisphere abruptly cooled. These climate changes weren’t as severe or long-lasting as the Younger Dryas, let alone the great glacial periods, but some may have been worse than anything we’ve seen since (at least, until now).
How in the world did gatherers and hunters survive these cold shocks at places like Star Carr? Were they vulnerable to climate changes, or adaptive and resilient? What, if any, secrets can they teach us? In this episode, we’ll find out.
Just after the Second World War, an amateur archaeologist by the name of John Moore wandered around carr-lands, meaning wooded wetlands, in the Vale of Pickering in North Yorkshire, England.
Moore was hunting for the remnants of ancient people, communities that lived in the area many centuries ago.
The search took him to the parish of Flixton, and in Flixton to a wetland named Star Carr, after a nearby farm. There, he found enough artifacts to warrant an excavation. He soon discovered that most of the artifacts were buried beneath a thick layer of peat – a layer that had accumulated within an ancient, now filled-in lake.
Moore doesn’t seem to have had a knack for naming things, because he called the lake “Flixton.” The lake, of course, is where that bone bounced off the platform.
A mutual contact connected Moore to Grahame Clark, a lecturer in archaeology at the University of Cambridge. Clark had earned his doctorate by carrying out the first detailed study of the Mesolithic in Britain, and here we should take a moment to define some terms we haven’t encountered yet.
So far, we’ve organized human history by climatic regimes: the Pleistocene with its glacials and interglacials, giving way to the Holocene (which is really an interglacial). Our species evolved in the Pleistocene, narrowly survived its climatic ups and downs, and then flourished in the Holocene.
You can also organize the history we’ve considered by focusing on how humans lived – not just the climatic conditions they endured.
In the Paleolithic, small but more or less networked hunter-gatherer communities lived diverse but overall mobile lives. Many followed migrating herds, for example, or tracked the seasonal appearance of different plants. They harnessed fire, used ever more sophisticated stone tools, began to develop symbolic culture – with shamanism and complex language – and, of course, responded to huge swings in climate.
People lived in Paleolithic for about 300,000 years. Then, in the Mesolithic, communities developed more advanced technologies, including small blades for harpoons or arrows. Many remained mobile, but their mobility was more constrained within territories that had grown warmer and wetter with the onset of the Holocene. Some began to more intensively cultivate plants – in the Levant, for example.
This stage began and ended at different times in different places, but in many regions it had started by about 11,700 years ago, and faded around 8,500 years ago. So the Mesolithic was relatively short – a hundred times shorter than the Paleolithic.
In many regions, the Neolithic came next, and it was all about the adoption of agriculture. Plant and animal domestication quickly forced most populations to stay in one place, but allowed those populations to grow in size and – to some extent – complexity. Later in the Neolithic, cities began to emerge, but people hadn’t yet discovered how to use metals. Again, this stage began and ended at different times, in different places. It seems to have started for the first time in the Levant, by about 10,000 years ago.
Now, you should always be suspicious when history is characterized in this way, as though one level of human development toggles smoothly into another. I’ve already criticized the teleological view of history that’s been popularized by video games like Civilization – or my personal favorite, Master of Orion.
So let me pick on them again. In games like Civilization, you’re in charge of a society, and you get your researchers to invent one technology after another until – bam! – you pass a threshold, your cities look different, your ships are bigger and better, you’ve got tanks rather than knights. You get the idea.
It’s a fun game mechanic, and to some extent, it does indeed reflect how researchers used to think about the past. That’s in part because it squared with how many scholars in the nineteenth and early twentieth centuries understood their present.
The idea that foraging societies, for example, hadn’t yet learned to be agricultural societies was something that helped to justify colonial rule – and colonial histories. According to this worldview, European settlers were entitled to rule because they could show the colonized how to level up to a new and better kind of civilization.
Obviously, we don’t look at our world that way now – or at least, we shouldn’t. And although the terms paleolithic, mesolithic, and neolithic still give us a convenient shorthand for different ways of living in the Pleistocene and early Holocene, archaeologists no longer believe that populations of the past simply switched from one of these lifeways to another, let alone that one was superior to the other.
Things were messy. As we’ve seen, some Paleolithic communities turn out to have stayed more or less in one place. Many Mesolithic groups migrated. Neolithic populations mixed foraging with farming, herding, or fishing.
Some societies never took up farming, but were still plenty complex – in Australia for example – while others took up farming, then abandoned it. Although archaeologists once thought that a coherent “package” of technologies and practices accompanied the Paleolithic, Mesolithic, and Neolithic, they now believe that nothing could be further from the truth. Pottery, for example, once seemed like a classic Neolithic innovation, but we now understand that it began in the Paleolithic. And a recent reinterpretation of thousands of mysterious markings on hundreds of Paleolithic objects – a reinterpretation enabled by machine learning – indicates that even writing may be at least 40,000 years old!
So, where does that leave us? Well, we still have our three broad categories. We just have to remember that one isn’t better than the other, that populations didn’t simply advance from one to the other, and that the boundaries between them are fuzzy.
Let’s go back to our archaeologist, Grahame Clark. When he heard from Moore, he trekked out to Star Carr and began a three-year excavation.
Wetlands, it turned out, provided unique opportunities to uncover and interpret the remains of Mesolithic settlements. It’s not only because wetlands tended to preserve materials like bone or wood; it’s also because they were full of ancient pollen. Deposits of pollen help archaeologists date bones or other remains that are in the same layer of a bog –and they suggest how environments were changing when, for example, someone kicked a bone off a platform.
Clark’s digging turned up a huge number of artifacts, and revealed that Star Carr had been a settlement on the edge of Lake Flixton. After he thought he had thoroughly excavated the settlement, Clark argued that it had been a winter camp for a group of early Holocene hunters who had followed the seasonal migration of red deer from the Vale of Pickering to the North York Moors.
It was an interpretation that would, for decades, shape how archaeologists understood the Mesolithic in Britain. It seemed like a time defined by the seasonal migration of small communities from upland to lowland, or inland to coastal, parts of the same territories.
But Star Carr was not completely excavated – not even close. The next wave of work on the site would not only transform how archaeologists understood Britain’s Mesolithic; it would also provide an unprecedented view of resilience to the climatic shocks of the early Holocene.
What does it mean to have a history?
It’s not just about having a past – at least, not if you define the word “history” like a historian does. History is about change. And to be a historian is to try to figure out not just what changed in the past, and when, but also and most importantly how, why, and with what effect.
So, if a people lives the same way, year after year, century after century, millennium after millennium, then in a sense they lack a history – again, at least as historians understand it. Of course, no community has ever actually lived like that. But Clark thought otherwise. Like many archaeologists, he assumed that people went about the same rhythms at Mesolithic sites from the time they were occupied to the time they were abandoned.
Clark had played a central role in revealing the existence of the people of Star Carr. But he had also robbed them of a history.
That’s partly why, about twenty years ago, a team of archaeologists returned to Star Carr. Their goal was to use all of the new tools available to archaeologists and scientists of the past – or in other words, paleoscientists – to, at long last, uncover the human and natural history of Star Carr. To learn how people’s experiences changed with their environments along the shores of Lake Flixton.
It’s clear that the lake didn’t exist during the Last Glacial Maximum. At that time, the gargantuan British-Irish ice sheet pushed all the way into the Vale of Pickering, the eventual home of Star Carr. Towards the end of the Last Glacial Maximum, the climate warmed, and the ice sheet began to melt. Water pooled against the remaining ice. Blocked from draining by the ice, it created an enormous lake, one that filled the entire vale of Pickering.
Lake Pickering existed for several millennia until it suffered a similar fate as Lake Agassiz, which we encountered in our tenth episode. At long last, the ice retreated enough for its water to surge into the North Sea. What remained was a landscape of silts and clays, one full of shallow depressions created by melting ice chunks and the uneven distribution of sediment carried by meltwater.
Overall, this landscape was rising, because the weight of the ice sheet no longer pushed it down. Remember, that rising is called isostatic rebound. Eventually, meltwater flowed into one of the depressions in the rising landscape, and the surrounding terrain was now high enough that the water didn’t just flow into the sea. As the climate warmed and grew wetter with the end of the Younger Dryas, plants flourished in and around the silts and clays of the depression, and peat began to form. Lake Flixton was born.
We know all this from deposits of sediments and pollen in and around today’s Star Carr archaeological site. And we know that, shortly after the dawn of the Holocene around 11,700 years ago, the first people arrived on the lakeshore. These people used a distinct kind of technology with long stone blades, and they seem to have used those blades to hunt, cut hides, and hack down trees around Lake Flixton. But they didn’t stick around, and they didn’t build any structures around the lake.
Why did they leave? And why does it seem like it took until about 11,300 years ago for a community to finally establish a truly long-lasting, seasonal settlement on the lakeshore – at Star Carr?
Part of the reason may be that the early Holocene climate was still quite unstable. The ice sheets were much smaller than they had been, of course, but they were still thawing. Meltwater lakes continued to explode into the ocean when the ice surrounding them passed a critical threshold in its retreat. The Atlantic Meridional Overturning Circulation, or AMOC – the huge pump that shapes the climate by moving warm, salty water north from the equator – was still vulnerable.
Let’s take a moment to go over this again, because it may be so important to our future, not just our past. In the steamy tropics, evaporation makes ocean water extra salty, or saline. Warm, tropical water cools down as it migrates north. Because it stays salty, it’s denser than the water that surrounds it. In the North Atlantic, the salty water sinks into the deep ocean.
This is the engine that keeps the AMOC going: the salinity of cooling water from the tropics. It’s also why the AMOC is vulnerable to global warming. Rising temperatures can cause the water to stay warm. Melting glaciers can lead it to mingle with freshwater, lowering its salinity.
Remember, that’s what seems to have happened when the waters of Lake Agassiz spilled into the Atlantic. And in the early Holocene, it continued to happen on a smaller scale, owing to smaller spills from smaller lakes. The AMOC didn’t shut down, but it did slow down, and that seems to have caused widespread cooling and drying across the Northern Hemisphere. It also influenced the flow of winds and patterns of precipitation in the Southern Hemisphere.
Climate scientists call these Abrupt Climate Events, or else Rapid Climate Change events. We can give them ominous-sounding names, like the “11.4 ka BP event,” with the “ka” standing for “kilo-annum,” or thousand years. This name refers to a sudden cooling that happened 11,400 years before our present, or “BP” – a cooling caused by a meltwater release into the Atlantic that slowed down the AMOC.
Unlike the Younger Dryas, the cooling didn’t last long – not more than a century. And although it was extreme by Holocene standards, it was a blip when compared to the chaos of the Pleistocene. But how much of a blip is hard to pin down.
Now, deposits of the hard mouth structures, known as head capsules, of midges, which thrive in warm water, hint that summer temperatures fell by about one and a half degrees Celsius around Lake Flixton, about 11,400 years ago.
Other kinds of proxy evidence for climate change, such as the oxygen and carbon isotopes in lakebed sediments, give us a messier picture of what happened. That’s because temperature had only an indirect impact on how they built up over time. Still, the isotopes suggest that, about 11,400 years ago, temperatures fell by a lot more than one and a half degrees Celsius in other seasons, perhaps especially winter.
And that’s exactly what we would expect during an AMOC slowdown. After all, in the North Atlantic, winds blow predominantly from the west. As they blow over the warm water that the AMOC pushes north, they gather that warmth and deliver it to Europe. This effect is strongest in the winter, when the Sun provides little direct heat. It’s why Europe has mild winters, relative to North America at the same latitude. But if the AMOC slows down, there’s less warmth to bring to Europe. Winter temperatures plummet.
In episode 10, I told you that the AMOC is slowing down today, and that it may heading for a total breakdown. In fact, that seems to be the most likely outcome if the world warms as expected in the coming decades. The AMOC will take a while to wind down, but the process is essentially irreversible once it starts. Remember: with the AMOC shut down, Europe’s winters get much, much colder.
It’s one example of the complexity of the climate system. Global warming can actually lead to extreme regional cooling – at least in the winter. And that’s what seems to have happened during what I’m calling the 11.4 ka BP event.
It might have been harder for Long Blade peoples to survive around Lake Flixton. And it might have been tougher for a Mesolithic group to get there.
Or maybe it’s just a coincidence that the story of Star Carr only begins after the cooling abated.
Three kinds of evidence tell us what happened after a Mesolithic community established itself beside Lake Flixton around 11,300 years ago.
First, there are – of course – the artifacts. The number of artifacts that have been recovered along the former banks of Lake Flixton is just remarkable. It’s a number that includes more than 4,500 pieces of wood!
And you have to remember that these remains are scattered across three dimensions. This means that they tell us where people did things – along the lakeshore, for example – and when they did things. The location of the imaginary bone our young woman kicked off the platform, for example, could tell us that she kicked it into the lake. And if the bone is deeper than, say, an arrowhead, then the kick probably happened before someone fired the arrow.
Second, there are the natural archives – the pollen and sediments and insect shells and fossils – that can tell us how the natural world changed around the people who left behind the artifacts. As we’ve seen, these archives aren’t perfect. They provide proxies, not direct measurements. They give us an indication of how things changed. And these things were only influenced by temperature or rainfall, not determined by them.
Third, there are radiocarbon dates – hundreds of them. Using a really sensitive method for radiocarbon dating, something called accelerator mass spectrometry, archaeologists dated wood, antler, charcoal, peat – you name it. Remember, radiocarbon dating measures the quantity of a radioactive isotope, carbon-14, in the remains of plants and animals, because those remains gradually lose the isotope at a predictable rate. So, the quantity of the isotope tells you about the age of the remains. And the archaeologists digging up Star Carr used advanced statistical methods to translate all of their isotope measurements into a range of dates during which, for example, somebody kicked a bone off a platform.
All of this evidence coalesces to tell us that when the first Mesolithic people arrived at Lake Flixton, they began to craft with wood, antler, and flint on the lakeshore. Debris from the work quickly began to accumulate in areas that were once under shallow water.
Our evidence also tells us that the Star Carr families were hunters, resembling the Long Blade peoples in taking down animals like red deer or elk. But their subsistence strategy seems to have been more diverse. They fished for pike and perch, eventually from the platforms they built in the water. They gathered seeds, berries, and tubers to eat, not to mention reeds, branches, and bark to work with.
It may be that, as soon as Mesolithic families began to occupy Star Carr for part of the year, they built huts near the water. Archaeologists have identified at least four of these huts, all built around shallow depressions, or hollows. Judging by the burnt bits of bone and flint in these hollows, it seems that people dug them to kindle fires – fires that wouldn’t easily climb up the sloping ground. The huts were domes, with walls thatched together out of branches, bark, twigs, and hides. Because they were built around the hollows, and probably reinforced with piled-up dirt, they would have been warm, sturdy, and dry in just about any weather.
It’s likely that there were other structures – sheds, for example, or dog shelters, or drying racks – that disappeared without a trace. And that’s not surprising. It’s actually amazing that we can find any traces at all of the huts. Ask yourself whether it’s likely that there’ll be any remnant of your home in 11,000 years!
As people were crafting their tools and weapons on the lakeshore, and probably after they’d built their huts, the climate cooled again. Another torrent of meltwater seems to have surged into the Atlantic Ocean, weakening its circulation. Once more, temperatures fell, and the cooling seems to have been worse outside of summer.
It’s likely that this cooling wasn’t as bad as the 11.4 ka BP event. Natural archives from across the North Atlantic suggest that the temperature drop during the new, let’s call it 11.1 ka BP event was about half as severe, maybe a third as severe, as cooling had been about three hundred years earlier. Summer temperatures seem to have dropped by one, maybe one and half degrees Celsius. Actually, the magnitude of the temperature change at Star Carr might have been similar to the magnitude of local warming today, since the late nineteenth century.
And the environment responded. Birch trees seem to have died out around Star Carr, open environments dominated by grasses and herbs expanded, and more sediments washed into Lake Flixton. That’s pretty amazing, because birch trees actually deal well with cold weather. That’s why they expanded into landscapes soon after glaciers retreated. For them to decline around Star Carr tells us that temperatures really dropped, even if it wasn’t as cold as it had been three centuries earlier, let alone during the Younger Dryas.
And this time, the area around Lake Flixton wasn’t abandoned. The Mesolithic community continued to occupy Star Carr. They kept hunting and fishing and gathering seeds, roots, and herbs. The climate changed, and they must have adapted – but their fundamental way of life stayed the same.
How did they do it? How were they so resilient in the face of climate change?
Here’s my take. In Mesolithic communities like Star Carr, small groups of people learned to use diverse resources in many different ways, with capable tools and time-tested practices, across huge territories. Different resources were differently impacted by climate change, and as long as the climate change wasn’t as severe as, say, the Younger Dryas, some resources weren’t impacted much at all. Lilies in the lake, for example.
Mesolithic peoples were flexible enough to compensate for relatively modest climate changes by exploiting old resources in new ways, or using new resources, or balancing a new mix of resources, all in one big territory. They were problem solvers, and their diverse environments gave them many ways of solving the problem of climate changes on par with the 11.1 ka BP event.
Climate changes of this magnitude seem to have mattered much more for bigger populations, the ones that started to grow with the rise of agriculture in the Levant. As we’ll see in this season, some of these populations depended precariously on the production, circulation, and stockpiling of just a handful of staple crops. In their complex agricultural systems, small differences between real and expected harvests could have outsized impacts for people who were just barely getting by. And in the ancient world’s agricultural societies, there could be thousands and even millions of those people.
But let’s return to Star Carr. After the cooling abated, the people of the lakeshore expanded their activities. They burned grasses and reeds to make way for larger platforms that stretched into the lake, and they may have built new huts.
Not everything seems to have worked out as planned. The platforms, for example, were quickly covered by sediment and plants. It’s possible that the people of Star Carr had to rebuild them, more than once. The site seems to have been deserted, for years or even decades at a time.
But for about eight centuries, the lake was never abandoned for long. A group of families always came back eventually, then stayed for a long time. Star Carr endured, even as its peoples and environments changed.
Of course, nothing lasts forever. Peat accumulated within Lake Flixton, gradually filling it, turning it into swampy wetland. The resources that had sustained generations of Mesolithic people gradually disappeared.
By about 10,500 years ago, Star Carr was abandoned for good. And the descendants of the people who had lived there moved on to greener – or wetter – pastures.
How should we make sense of the human and natural histories of Star Carr?
Have I just told you a story of human vulnerability to climate change? After all, it was impossible for people to even reach the Vale of Pickering when it was full of ice, or filled by a giant lake. People came only when the environment allowed it, and then they left for a while as that environment cooled down, 11,400 years ago.
Or have I told you a tale of adaptation? Communities quickly exploited the retreat of the British-Irish ice sheet and the northward migration of plants and animals. People moved to take advantage of a changing climate. When Mesolithic families decided to settle in one place for part of the year, they may have adapted to cooling by changing the resources they used.
Or did you just read a story of resilience, which includes not only adaptation but also resistance to the effects of climate change? In the late Pleistocene and early Holocene, people survived in northwestern Europe even as the climate changed dramatically around them. Some populations declined, but many recovered. The people of Star Carr carried on, living on the shore of Lake Flixton and harvesting its resources even as the climate changed around them.
To me, that’s what stands out. I see that young woman in my imagination, kicking the bone into the lake, not knowing what the future has in store – but believing she could survive it. That her community could endure.
The story of Star Carr involves people totally different from you and me, living in a world we might not recognize.
All the same, it gives me hope.
For Teachers and Students
Review Questions:
- What were the Paleolithic, Mesolithic, and Neolithic? Did populations transition from one level of development to another?
- What does it mean for a population to have a history, as historians define history?
- What evidence can tell us about the human and natural history of Lake Flixton and Star Carr? What are the limitations of this evidence?
- How could the Mesolithic people of Star Carr have endured sudden cooling, 11,100 years ago?
Key Publications:
Milner, Nicky, Barry Taylor, and Chantal Conneller. Star Carr Volume 1: A Persistent Place in a Changing World. White Rose University Press, 2018.
Blockley, Simon et al., “The resilience of postglacial hunter-gatherers to abrupt climate change.” Nature Ecology & Evolution 2:5 (2018): 810-818.
Video and Audio Credits:
Audio: AIVA, Podbean, LALIA.
Video: Runway, Sora II.
Funding provided by Georgetown University’s Earth Commons.
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