People returned to the British Isles around 15,200 years ago after the last major ice sheet began to retreat, according to new research. That timeline is nearly 500 years earlier than previous estimates suggested.
The return of humans appears to have coincided with a sharp rise in summer temperatures in southern Britain. At the time, Britain was still connected to mainland Europe, allowing people and animals to move across the landscape more easily.
Early humans likely followed herds of reindeer and horses north to newly opened grasslands that could support herbivores. These hunting opportunities, combined with warmer conditions, may have made the area re-inhabitable after a long period of extreme cold.
After the last ice age, northwestern Europe experienced at least two major changes from cold to warm climates. Scientists believe that these temperature changes occurred rapidly, perhaps over just a few decades.
The latest study focused on the first period of warming during the Upper Paleolithic period (14,000 to 11,000 years ago). During this time, as climatic conditions changed dramatically, people repeatedly abandoned and later returned to areas throughout northwestern Europe.
Fossil evidence has long shown that humans tend to migrate to areas with environments that can support their survival.
Reconsidering the UK’s post-Ice Age population resurvey
The return of humans to Britain after the last Ice Age provides an important opportunity for scientists to study how changes in climate and environment have affected migration and survival.
Early research faced challenges due to poor dating techniques and incomplete environmental records at the time. Researchers have traditionally believed that northwestern Europe warmed significantly around 14,700 years ago, and that humans returned to Britain after that warming occurred.
However, improvements in dating methods in the early 2000s changed that. A new analysis of human remains and associated artefacts has shown that humans may have appeared in Britain before the warming event previously thought necessary for survival there.
The results created a puzzle for scientists, as the climate at this time was still believed to be extremely cold and difficult for humans to endure.
Wales’ ancient lake reveals clues to climate change
To investigate further, the researchers readjusted the radiocarbon dates associated with the human bones. New analysis confirms that humans were present in Britain between 15,200 and 15,000 years ago.
This raises an important question. Did humans actually live in colder glacial conditions, or did scientists misunderstand what Britain’s climate was actually like at the time?
The answer came from Loch Llangors (Lough Syfadan) in south Wales. The sediments preserved in the lake contain a detailed environmental record spanning the past 19,000 years. The site is also close to the Wye Valley Caves, where some of the earliest evidence of post-Ice Age humans in Britain was discovered.
The researchers analyzed fossil pollen, midges (non-stinging midges), and chemical signatures preserved in the lake’s sediments. The results showed that early reconstructions of the region’s climate were probably wrong.
Chironomids helped scientists estimate ancient summer temperatures. Their findings showed that the UK was warming differently than the rest of northwest Europe and Greenland. Around 15,200 years ago, summer temperatures appear to have risen from around 5-7 degrees Celsius to 10-14 degrees Celsius in Britain, about 500 years earlier than previously thought.
Reindeer, horses, and human migration
Evidence suggests that reindeer and horses were already becoming common in southern Britain just before the warming period, about 15,500 years ago. These animals took advantage of the grazing areas that expanded as the environment improved.
Humans likely followed these herds north into Britain, adapting to slightly warmer summer conditions.
By combining archaeological evidence with climate and environmental records, researchers were able to build a more precise timeline for when humans could re-enter areas that were once too inhospitable. By reevaluating old radiocarbon dates and improving climate reconstructions, scientists can now pinpoint more precisely when the transition from cold to warm conditions occurred.
This study provides a clearer understanding of how people responded to environmental change during the Upper Upper Paleolithic. Human survival drove these migrations, and access to prey animals was important. The researchers also found that relatively modest increases in summer temperatures could be enough to trigger large-scale population movements.
This finding may still be relevant today. Scientists say studying how humans responded to climate change thousands of years ago could help improve our understanding of how modern humans will respond to environmental change in the future.
As the polar regions continue to warm and glaciers melt, the same fundamental pressures that shaped ancient human migrations could once again influence where people can live.
