How China created artificial islands by dumping sand into the sea in just one decade

The idea of constructing an island in the middle of the ocean is not new. Decades ago, cities like Miami and San Francisco reshaped their shallow waters to extend their beaches. However, large-scale island building has been occurring farther away from any shore in recent years. Submerged reefs in the South China Sea have become permanent artificial islands due to widespread land reclamation. Although shipping routes and infrastructure are frequently mentioned in relation to these projects, their environmental impact is not as well-known. The Spratly Islands are located in one of the world's most biologically diverse oceanic environments. Here, seafloor landscapes that took thousands of years to build have been changed by construction activities. Marine biologists caution that more significant ecological harm below the surface may be indicated by the physical alterations that are now apparent from satellites.Creating land in the middle of the sea requires enormous quantities of material. Dredging ships scrape sand, coral and sediment from the seabed, often from nearby reefs and lagoons. This material is then pumped onto shallow features until they rise above the waterline.The process stirs up fine sediment, which can drift for kilometres. Suspended particles reduce sunlight penetration, making it harder for corals and seagrasses to survive. Once settled, the sediment can smother living reefs, blocking the flow of water and oxygen, disrupting habitats, killing marine organisms, altering local currents, reducing biodiversity, and causing long-term ecological damage to fragile ecosystems. Coral reefs are not simply rocks. They are living structures that coral creatures have steadily developed over the years. When reefs are buried beneath sand and concrete, the organisms that make them perish. Reefs in the Spratly Islands provide habitat for a diverse range of animals, from little reef fish to larger predators. They also act as breeding grounds for larvae, which replenish fisheries throughout the South China Sea. Damage to these reefs has far-reaching consequences for ecosystems beyond the construction sites themselves. Marine biologists believe that once a reef has been devastated on this magnitude, rehabilitation is unlikely within any human timeline.The South China Sea contains some of the highest marine biodiversity in the world. Its reefs, seagrass beds and open waters support endangered species including sea turtles, sharks and giant clams. Many coastal communities around the region depend on these ecosystems for food. Fish stocks that spawn or feed around the Spratly reefs supply fisheries hundreds of kilometres away. Disrupting these habitats can weaken already stressed fish populations. Scientists note that environmental damage in shared waters rarely stays local.Natural reefs shape currents and waves in subtle ways. When they are replaced with solid land and concrete walls, water flow changes. Altered currents can increase erosion in some areas while causing sediment build up in others. This can affect nearby reefs that were not directly dredged. Changes in wave patterns may also influence how nutrients and larvae move through the region. These secondary effects are difficult to predict and even harder to reverse.Experts generally agree that the damage caused by large-scale reef burial is permanent. Unlike oil spills or surface pollution, the physical destruction of reef structures gives little opportunity for recovery. Some artificial islands have features like restricted green space or energy installations. These do not replenish depleted ecosystems. Coral restoration efforts do exist, but they are on a limited scale and require stable, undisturbed circumstances. In significantly disturbed environments, marine life frequently shifts rather than returns.From above, reclaimed islands appear solid and orderly. Below the waterline, the picture is less clear. Broken reef fragments, altered seabeds and disrupted habitats tell a quieter story. Marine scientists continue to study the long-term effects, though access to some sites is limited. What is already evident is that island building in sensitive waters carries costs that extend well beyond the visible shoreline.Information is based on a publication ofEarth Island Institute.