'Great wall of sand' in South China Sea

A new islands was build entirely from scratch by pumping sand from the seabed by China 

Department of Foreign Affairs, a Chinese vessel, was used to expand structures and land on the Johnson Reef, called Mabini by the Philippines and Chigua by China, at the Spratly Islands in the South China Sea, Philippines. China's land reclamation is creating a "great wall of sand" in the South China Sea. For more than a decade, fleets of dredgers have been pouring sand onto remote reefs in the South China Sea, turning shallow coral platforms into solid ground with runways, ports and radar domes. What looks like a technical triumph from space comes with a heavy ecological bill under the waves. Scientific studies now show that this construction has smothered coral reefs, clouded vast areas of water, and put one of the planet’s richest marine ecosystems under even greater stress.

US Pacific Fleet Commander Admiral Harry Harris said by pumping sand on to coral reefs and adding concrete, China had created "over 4 sq km (1.5 sq miles) of artificial landmass. China has overlapping claims with neighbours in the South China Sea. It has been reclaiming land in contested waters - something it said earlier was "totally justified" as it had "sovereignty" over the area. At first glance, all this might sound like a distant quarrel over faraway sandbars. Yet the South China Sea is a key artery for the global economy and a pantry for millions of people. Roughly one-third of global maritime trade by volume passes through these waters, carrying everything from smartphones to grain. Biologically, the stakes are just as high. The region sits on the edge of the Coral Triangle and hosts one of the highest concentrations of marine biodiversity on Earth. Hundreds of reef forming coral species and thousands of fish species rely on South China Sea habitats. For coastal communities, those reefs are not an abstract wonder. They are protein on the plate and income at the dock. When island building destroys nursery grounds and disrupts currents which carry larvae, the effects ripple far beyond the footprint of any one runway. Experts warn that this disturbance piles on top of warming seas, acidification and heavy fishing pressure.

Several nations, including Vietnam, the Philippines and Taiwan, also claim ownership of territory in the Spratly Islands. It was described China's land reclamation as "unprecedented". China is building artificial land by pumping sand on to live coral reefs - some of them submerged - and paving over them with concrete. China has now created over 4 sq km (1.5 sq miles) of artificial landmass. China is creating a great wall of sand with dredges and bulldozers over the course of months. China's "pattern of provocative actions towards smaller claimant states" in the South China Sea, the scope of the building raised "serious questions about Chinese intentions. Engineers started with low-tide features which barely broke the surface. Cutter suction and hopper dredgers scraped sand and rubble from nearby sea beds and pumped the slurry onto reefs such as Mischief, Subi and Fiery Cross. Bulldozers then leveled and compacted the new material, while concrete walls tried to hold the whole structure in place against waves and storms. From orbit, the change is stark. A earlier study using Landsat data estimated that more than fifteen square kilometers of submerged coral reef were converted into artificial islands, mostly by China. A later analysis in Scientific Reports found that China built about 3,200 acres of new land in the South China Sea. In practical terms, it is thousands of football fields of former reef replaced by concrete and fill. Once the outline is fixed, the islands are fitted with power plants, desalination units, fuel depots and storage. Some patches of imported soil and trees soften the view, but ecologists remind us that the true foundation is living rock which have been buried rather than respected.

In recent months images have emerged of Chinese construction on reefs in the Spratly Islands to create artificial islands with facilities which could potentially be for military use, including an air strip. The row over territory in the South China Sea has escalated in recent years, raising regional tensions. The most visible damage to coral reefs does not end with the new shoreline. It spreads outward in cloudy plumes. The satellite study detected turbidity plumes linked to island building which together covered more than 4,300 square kilometers of surrounding waters. A case study at Mischief Reef went further. Using ocean color data, researchers measured backscatter increases of up to 350% in nearby waters and estimated that dredging and construction affected more than 1,200 square km's over time. Those suspended sediments act like a dust storm in the sea. They block light, clog coral polyps and settle onto sea grass beds and other benthic habitats. The same study found changes in chlorophyll and other optical signals which point to declining biological health around the construction site, consistent with reefs and associated communities being smothered. Once complex coral structures die back, fish lose shelter and feeding grounds. What used to be a vibrant three-dimensional city becomes a flattened, muddy lot.

Unlike natural islands, these new platforms do not grow with the reef. They constantly battle erosion, salt and storms while the corals beneath them are already gone. This leaves the surrounding ecosystem with fewer buffers just as climate-driven bleaching events become more frequent. For people far from Asia, the connection can feel indirect. Yet any shock to South China Sea fisheries and shipping can eventually show up in seafood prices, freight costs and even the availability of certain products in supermarkets. At the end of the day, manufactured land in one contested sea is entangled with everyday life in places which will never see these islands firsthand. Scientists say that detailed satellite monitoring, strict limits on further dredging, and stronger regional conservation efforts are essential if the remaining reefs are to avoid long-term collapse. China's foreign ministry spokesman said China's operations in the Spratly Islands fell "entirely within China's sovereignty and are totally justifiable". Asked whether the reclamation was for commercial or military use, spokesman replied that it was "mainly for the purpose of improving the working and living conditions of people stationed on these islands".