In Germany, the island of Sylt is battling against disappearance. Its beaches, like those of other North Sea islands, have been under assault for decades. Authorities are trying to halt the loss of kilometers of sandy beaches with construction measures and beach nourishment. Big sand dredging ships play an important role in this process. They remove enormous quantities from the seabed and pump it back onto eroding shores. 
Replenishing an shorelines in this manner costs several million euros a year. But the financial expense is not the only problem - the ecological price of these significant interventions into the fragile maritime ecosystem is far from clear. Currently, people are still putting coastal protection before environmental protection. But there are debates about whether this strategy can be continued in future. After all, sand is the second most important commodity in our modern society after water. It can be found in concrete, cars, computer chips, cleaning detergents and cellphones. And because desert sand is too fine, all of this sand has to come from the sea or from rivers. 
In total, between 40 and 50 billion tons of sand are used each year. As a result, sand has gradually become a scarce resource. Meanwhile, many countries have seen a rise of illegal sand mining organized by criminal gangs. Sand mafias plunder and destroy entire regions. The workers who remove sand from beaches, the sea, or riverbeds often do so under hazardous conditions. 
Researchers are working hard to find replacement materials and innovative recycling processes. Sand may seem essentially limitless, but global demand far outstrips availability.