Lajme nga Bota

The earth is sinking under the weight of metropolises

The earth is sinking under the weight of metropolises

Many cities are sinking. Jakarta is the most famous, perhaps because the Indonesian Parliament has already passed a law that envisages the construction of a new capital in Borneo, with an investment of 35 billion dollars and the gradual transfer of 10 million inhabitants. The first phase of the project is expected to be completed this year, with enough buildings to accommodate 60,000 people.

But all over the world there are metropolises that are sinking, more or less slowly, and it's not just coastal cities due to rising sea levels. The main cause is subsidence, i.e. the subsidence of the land due to the extraction of water or rocks from the subsoil, the compaction of sediments under the weight of buildings and transport systems.

According to an article published in the journal "Science", almost half of the surface of China's big cities is sinking at a rate of 3 millimeters per year, but one sixth of their surface is doing so at a rate of 10 millimeters. or more.

The authors, led by Tao Shengli of Peking University, measured with satellite instruments the change in elevation of 82 cities with a population greater than 2 million between 2015 and 2022, finding that cities experiencing severe subsidence are concentrated in five regions and that the most endangered are coastal cities: within a century, almost 130 million inhabitants of these metropolises could be below sea level.

But this does not mean that these people should undergo forced migration. In recent decades, some cities, such as Tokyo and Osaka in Japan or Shanghai itself in China, have been able to correct severe subsidence by drastically reducing groundwater extraction and adopting other environmental measures. It is now a matter of moving from measures to countermeasures.

Originally published on