New research has revealed that New York City is sinking due to the weight of its buildings. This phenomenon could trigger significant flooding problems for the city, which already struggles with rising sea levels above the global average. It is projected that the sea level will continue to rise between 8 and 30 inches by 2050 and cities with coastal, riverfront, or lakefront areas need to take into account the sinking ground due to human activities.
The study, published in the journal Earth’s Future, estimates that the 1,084,954 buildings across the five boroughs of New York City weigh about 1.68 trillion pounds (762 billion kilograms) - roughly equivalent to 1.9 million fully loaded Boeing 747-400s. The researchers calculated that over time, the weight accumulates and gradually compresses the ground beneath, leading to the sinking of the city. They found that the city is sinking an average of 1 to 2 millimeters per year, with areas, such as low-lying Brooklyn, Manhattan, and Queens, sinking at a faster rate. The subsidence, which is the sinking or settling of the Earth's surface due to natural or artificial causes, can pose significant flooding threats, such as seen during the natural disaster events of Hurricane Sandy and Ida.
Researchers fear that not only is New York City experiencing this type of problem, but it appears to be a global issue. Jakarta is sinking so fast that the Indonesian government is already planning to construct a new capital city elsewhere. Similarly, and as reported elsewhere, in 2019, Mumbai was reported to be sinking ten times faster than it previously thought - at a rate of 13 millimetres per year - than the average global rate. The study's authors suggest that cities worldwide will need to mitigate flood risks derived from land subsidence.