Denmark’s seabed extraction equals 700,000 truckloads a year, threatening marine life

A coalition of industry and environmental groups is urging Denmark’s next government to prioritise a national strategy for sourcing construction materials, warning that current seabed extraction is devastating marine ecosystems, DR reports.

Each year, 14 million cubic metres of sand, gravel, and stones—equivalent to 700,000 truckloads—are dredged from Denmark’s seabed to supply infrastructure projects like highways, hospitals, and coastal defences. The practice is destroying habitats critical to marine life, according to the think tank Tænketanken Hav and industry group DI Byggeri.

“When we extract sand, gravel, and small stones from the seabed, we’re not just removing the seabed—we’re sucking up all the small animals and plants that live in and on it,” said Mathilde Højrup, senior advisor at Tænketanken Hav. “We’re simply removing the habitats for marine life, and we urgently need a solution.”

The extracted materials support species like seaweed, mussels, and bristle worms, which fish depend on for survival. Højrup warns that deep pits left by dredging often never recover, while disturbed sediments spread and smother surrounding areas.

Demand for marine-sourced materials is surging, with projects like Copenhagen’s Nordhavn Tunnel alone requiring over 337,000 tonnes of sand. Yet Denmark still lacks a promised national raw materials strategy, despite repeated political commitments.

“If the incoming government prioritises defence expansion, new hospitals, and coastal protection, the raw materials strategy must be at the very top of the agenda,” Højrup said, noting that the plan has been included in government platforms for years but never implemented.

Local impacts are already visible. In Karrebæksminde Bay, three decades of dredging by Næstved Sten og Grus have left the seabed depleted, while fishermen report dwindling catches. “The fish are getting thinner and thinner,” said Morten Jacobsen of Danmarks Sportsfiskerforbund. “It’s not the fish who decided we needed highways.”

Industry representatives argue that new extraction sites must be identified—but with stricter environmental safeguards. “Permits must respect both the environment and local communities,” said Flemming Schou, director of Næstved Sten og Grus, emphasising the need for urgent planning.

Environmental groups stress that seabed dredging should face the same scrutiny as onshore gravel pits. “The marine environment is already struggling,” said Henriette Gaborit of Danmarks Naturfredningsforening. “It’s frustrating to see sand extraction worsen the damage, whether here or elsewhere.”

Proposed solutions include reducing consumption, increasing material reuse, and adopting less destructive dredging techniques to allow ecosystems to recover. Without political action, critics warn, Denmark’s construction boom will continue to erode the foundations of its marine life.