If someone lacks land on dry ground, they can reclaim an island in the sea
Cities in different parts of our planet are expanding at the expense of the sea. Plans are being developed for the construction of huge islands and giant structures in coastal areas, involving the excavation and dumping of millions of tons of soil. What could be the consequences of the constant increase in construction volume in the sea for its inhabitants and ecosystems? This and many other similar questions were discussed at the BBC Future summit "Ideas That Will Change the World" in Sydney in November of this year.
Cities have been expanding their borders at the expense of marine territories ever since people first began building harbors. The construction of reclaimed land has turned into big business, and today many countries seek to reclaim land from the sea to increase the length of their coastline and the area of their territory.
Thus, almost every province in China with access to the sea is implementing projects to create artificial coastal territories. Methods include dumping soil from the mainland, extracting soil from remote areas of the seabed, and blocking river mouths to collect silt deposits.
The island state of Singapore has managed to expand its territory by 22% over the past 50 years through construction in surrounding waters. Materials such as sand, soil, and stone are used, which are delivered from other countries. Singapore's ambitions in the field of land reclamation are so great that the state has become the world's largest importer of sand.
But the most famous territories reclaimed from the sea are in Dubai. One of them is the completely artificial picturesque archipelago Palm Jumeirah, which has become home to many wealthy people. Its construction used approximately 110 million cubic meters of sand extracted from the seabed.
The low-lying Netherlands, one of the most densely populated countries in the world, has long had to drain huge areas of swampy coastal lands to provide housing for its constantly growing population.
For ocean ecosystems, there is nothing good in this. Emma Johnston from the University of New South Wales, who spoke at the BBC Future summit "Ideas That Will Change the World," argues that we should seriously consider the consequences of cities capturing land from the sea. Even relatively small coastal structures can change the appearance and biosystems of the seas. Together with her colleagues, Johnston calculated that more than 50% of the natural coastline of estuaries in Australia, the USA, and Europe have been altered as a result of the construction of artificial structures.
"The reality is that urban sprawl today is happening not only on land," she wrote in an article for the online magazine The Conversation. "Territories that once belonged to the sea are being built up, and complex structures appear under the water's surface." This has a destructive impact on marine organisms and their habitats, leading to the death of coral reefs that serve as homes for many fish species and protect the coastline from the harsh effects of waves, as well as disrupting the stability of many valuable coastal ecosystems, including salt marshes and mangrove forests.
Buildings constructed on sedimentary deposits pose risks to their occupants, as these layers are not as stable as solid mainland soil. For example, there have already been reports that the Palm Jumeirah archipelago in Dubai is beginning to sink into the water.
Reclaimed land also poses a threat in seismically active areas. During prolonged earthquakes, a liquefaction process can begin, in which the soil partially loses its strength. This factor played a significant role in the destructive consequences of the 1906 San Francisco earthquake.
Given that as a result of the construction of artificial territories, the line between land and sea is gradually blurring, disputes over their ownership have added a lot of work for lawyers. Particularly controversial have been China's attempts to build coral atolls from sand and create more than 13 square kilometers of new land in the southeast of the South China Sea, not least because many of these new islands are now occupied by military facilities. Although China claims that these islands are Chinese territory, many countries, including the USA and Australia, disagree. In July of this year, the International Court of Arbitration in The Hague ruled that China does not have historical rights to use this region, but saber rattling continues, and it is unlikely that this issue will be resolved in the near future.
But why don't people build floating buildings? There is nothing impossible about this. Floating villages have existed for a long time—for example, residents of Cambodia live in floating houses on the freshwater Tonle Sap Lake, and on Lake Titicaca in Peru, the Uros Indians live on floating islands built from bundles of reeds.
Architects around the world are creating more and more modern floating homes, which are especially popular in flood-prone countries such as the Netherlands. High-tech floating cities (or even large-scale living areas) have not yet become a reality, but this does not stop various organizations, in particular the Seasteading Institute, from calling on designers to share their concepts of futuristic floating megacities and their functioning. Their idea is not only to create new environmentally sustainable territories but also to promote the emergence of "startup cities," thereby introducing a spirit of innovation into the field of urban construction.