At the beginning of the last ice age, our ancestors did not yet live in Northern Europe. But the Neanderthals (Homo neanderthalensis) did. They hunted woolly mammoth by driving them off cliffs.

As the climate cooled, a number of small independent ice sheets began to form. An ice sheet is a large mass of ice that builds up with increased snow over mountains and then flows outwards. These ice sheets formed across Britain, Scandinavia, Iceland and one in the far north across the Barents Sea.

Modern humans (Homo sapiens sapiens) established themselves in Southern Europe. At the same time, Neanderthals mysteriously disappeared from the North. Many believe that the reason they went extinct, is the sudden cooling of the climate leading to fewer animals and plants to eat.

Many species began to die off because of climatic and environmental changes brought about by the ice age. The cave bear (Ursus speleaus) was one of these animals. It was much larger than today’s grizzly bear, but unlike the polar bear, it was not well adapted to frozen conditions.

The ice cover changed the landscape and climate patterns. The ice sheets stole all the moisture from the air to the west. This meant that areas further east, like Siberia, became a polar desert.

The three main ice sheets merged across northern Europe to form continuous ice cover stretching from the British Isles to Arctic Siberia. At the time of this glacial maximum, this immense ice sheet was over 3000 metres thick in places. For comparison, the mountain overlooking Tromsø – Tromsdalstinden, is just 1242 metres high.

When the ice age was at its peak, global sea levels were over 120 metres lower than today. At the same time, the heavy weight of the ice sheets also  pressed down on the land and seabed (called glacial isostatic depression).

During the Last Glacial Maximum, it would have been possible to ski across this massive ice sheet continuously for over 4500 km: from the far Atlantic isles of western Britain to deepest Arctic Siberia.

The ice sheets began to retreat as the climate warmed. An enormous river system formed across Western Europe draining into the Atlantic through northern France: the Fleuve Manche. It drained many rivers including the present-day Vistula, Elbe, Rhine, Seine and Thames, as well as capturing melt from the shrinking ice sheets.

Climate warming started to accelerate: as the ice sheet continued to retreat more of the sun’s energy was absorbed by the darker land surface. Animals began to migrate northwards and settle in new areas where the ice sheets once stood. Modern humans – hunters and gatherers – followed soon after.

Due to lower sea levels, some of today’s seabed became habitable – particularly an area in the North Sea known as Doggerland. Also, parts of the Irish Sea became a large forest. People lived there, hunting and foraging for shell fish, until these areas were eventually flooded under rising seas.

As the sea became warmer, ocean currents started eating away at neighbouring parts of the ice sheet. Ice in these marine areas quickly retreated, often with dramatic consequences, calving vast armadas of icebergs and causing periods of rapid sea level rise.

In the Barents Sea hundreds of kilometre-wide craters formed on the ocean floor. The thick ice kept a lid on large reservoirs of a potent greenhouse gas – methane. But as the ice disappeared, enormous amounts of methane abruptly escaped, forming the craters.

As the ice melted, a large ice lake formed where the Baltic Sea is today. Eventually, the ice and land dam that could not hold the water any more. It breached and flooded into the Atlantic Ocean. Eventually the English Channel flooded too.

As the last remnants of the ice sheet melted, people migrated northwards. They traveled  from what is Germany and Russia today. Excavations in the far north of Norway reveal Stone Age foragers and hunters well adapted to the environment.

The forest land between Ireland and Britain was flooded to become the Irish Sea. This happened earlier than flooding of the English Channel, between Britain and Europe. For this reason there are no snakes in Ireland, yet there are snakes in Britain. They could not cross the Irish Sea.

As the pressure from the shrinking ice sheet lifted, the seabed – loaded with glacial sediments – became unstable. This led to a massive underwater landslide known as the Storegga slide. It caused a 50-metre high tsunami that flooded the Norwegian and British coastlines, as well as inundating the last remnants of Doggerland.

The giant deer (Megaloceros giganteu) became extinct. With its enormous antlers, it was well adapted to life on open plains. However, once the climate warmed and the forests grew, the deer’s antlers got stuck in the branches. They quickly became easy prey for predators, including humans.