At the last Ice Age’s coldest, so much ocean was locked in ice sheets that sea level stood some 120 metres lower — and the basin of the North Sea was land: a great plain of rivers (the Thames and Rhine met and flowed south together), lakes, reedy marshes, and low hills, running unbroken from Yorkshire to Denmark. Archaeologists christened it Doggerland, after the Dogger Bank — itself one of its drowned uplands — and have come to argue it was not a mere land bridge but the heartland: some of the richest hunting, fowling, and fishing territory in Mesolithic Europe, with Britain as its western ridge.
Its inhabitants surface in fishermen’s nets. Trawlers working the banks have hauled up mammoth and reindeer bone by the ton, peat blocks (“moorlog”), and — the find that started scientific attention — a barbed antler harpoon point brought up by the trawler Colinda in 1931 from beneath 36 metres of water. Since the 2000s, seismic survey data donated by the oil industry has let archaeologists map the drowned country itself — meandering river channels, estuaries, salt marshes — across tens of thousands of square kilometres: Europe’s best-preserved prehistoric landscape, unvisitable under the busiest sea lanes on Earth.
The drowning, slow then sudden
Doggerland died mostly by degrees: meltwater sea-level rise of metres per century at its worst, salt creeping up the river mouths, hunting grounds becoming mudflats becoming sea, over a hundred generations who each knew the water was higher than their grandparents’ stories said. By around 6500-6200 BC the plain had thinned to a great archipelago around the Dogger uplands.
Then, off Norway around 6150 BC, the edge of the continental shelf failed: the Storegga slide, one of the largest submarine landslides known — some 3,000 cubic kilometres of seabed, a volume like a small country — collapsed into the deep, and the displaced ocean crossed the basin as a tsunami. Its sands lie metres above the ancient shorelines of Scotland (25 metres up at some Shetland sites) and down the North Sea coasts; at the Norwegian and Scottish coastal camps in its path, autumn-season occupation debris under the tsunami sand suggests the wave arrived when people were there. For the low remnant islands of Doggerland — recent research debates how much still stood above water — the wave was somewhere between the killing blow and the funeral: within centuries, at most, the sea closed over the last of it, and Britain was an island.
Climate scientists note the period’s driver with interest: the 8.2-kiloyear cold event and meltwater pulses of a deglaciating world — which makes Doggerland the standing exhibit, currently being surveyed for wind farms, of what a few metres of sea level do to a civilisation’s map. Every fisherman’s net on the Dogger Bank is trawling somebody’s country.