The secrets of the underwater world: May the depths of the North Sea and the Baltic Sea conceal traces of lost civilisations?

The underwater world hidden beneath the North Sea and the Baltic Sea could reveal new information to archaeologists about once-thriving ancient human civilisations. International research teams are attempting to uncover the secrets of former coastal plains, while racing against time: modern offshore developments could permanently block access to the discovery of prehistoric remains.

Exploring the depths of the oceans and seas has long been a key objective for researchers, and in recent years it has become increasingly clear that the underwater world is an exceptionally important repository of humanity’s past. The areas now lying on the seabed of the North Sea and the Baltic Sea were once coastal landscapes; they are not merely geological formations, but formerly inhabited and flourishing regions that contain crucial information about prehistoric civilisations, writes Popular Mechanics.

When the seas were still dry land

Around 8,000–6,000 years ago, vast and fertile plains stretched across what is now the North Sea and the Baltic Sea, providing a home for ancient human communities. These groups initially lived as hunter-gatherers and later gradually settled down. With the end of the last Ice Age, however, a period of intense warming began, leading to a dramatic rise in sea levels. Water gradually flooded these low-lying areas, turning them into part of the underwater world.

Although it long seemed that these civilisations had vanished without a trace, modern science has now proven that their remains are still hidden on the seabed. The question, therefore, is no longer whether these communities existed, but whether their traces can be uncovered in time.

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SUBNORDICA: research in the depths of the sea

To address this challenge, the international research collaboration known as SUBNORDICA was established, involving several Northern European institutions. Participants in the project include the University of Bradford’s Centre for the Study of Submerged Landscapes, the Netherlands Organisation for Applied Scientific Research (TNO), the Flanders Marine Institute, and the University of York. Their aim is to identify evidence of former human presence in previously unexplored areas of underwater landscapes.

One of the most important sites of the research is Doggerland, which may have been a thriving region in the North Sea area around 8,200 years ago. This area plays a key role in understanding how people lived and adapted to environmental changes before the water finally destroyed their settlements.

Cutting-edge technology in exploring the underwater world

SUBNORDICA researchers employ the most advanced technologies to map the underwater world. They use computer simulations and artificial-intelligence-based analytical tools, as well as seismic and acoustic surveys and drilling, in order to gain an accurate picture of the structure of the seabed.

The University of Bradford has previously collected data using magnetometer surveys, originally intended for environmental impact assessments of future green-energy projects. These data, however, are also extremely valuable from an archaeological perspective, as they help identify areas where peat formation occurred or where erosion shaped the landscape, for example in former riverbeds.

A race against time

According to researchers, several thousand years ago there was approximately 7.7 million square miles more dry land on Earth than there is today. A significant proportion of this lay along the coastlines of present-day Europe, and experts believe these were the continent’s most attractive areas for prehistoric settlement.

The rapid expansion of green-energy infrastructure, however, poses a serious challenge for science. Industrial developments can restrict access to research areas, meaning that archaeological exploration of the underwater world has quite literally become a race against time. SUBNORDICA’s objective is therefore to document the structural characteristics of former human settlements before larger-scale interventions take place.

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Lessons from the past

Through diver surveys conducted in Denmark’s Aarhus Bay, researchers are also examining how densely populated and how common coastal settlements were, and how people exploited marine resources 8,500–9,000 years ago. These findings may help to launch more targeted archaeological investigations even in areas that are more difficult to access.

As modern societies today struggle against rising sea levels, the exploration of the underwater world serves as a reminder that humanity has faced similar challenges before. The story of ancient civilisations thus not only helps us understand the past, but also serves as a warning for the future: adapting to environmental change has always been one of the greatest trials of human existence—and it seems it always will be.