Coastal cities are sinking due to sea level rise

Many of the world’s most densely populated coastal cities are vulnerable to sea level rise due to Much of their land is sinking quickly.

A team of international scientists, led by Nanyang Technological University (NTU Singapore), is proposing an increase in industrial processes such as extraction of groundwater, oil and gas, In addition to the rapid construction of buildings and other urban infrastructure, it may contribute to this weakness.

For a period of six years, from 2014 to 2020, The team of researchers took satellite images of 48 cities It used a cloud-based processing system called Interferential Synthetic Aperture Radar (InSAR).

as such Sea water is heated The ice caps of the earth are melting, Sea levels are rising globally. Sea level rises At a rate of 3.7 mm per year globally. Now that problem could be exacerbated by subsidence of the Earth, according to NTU scientists.

Although the subsidence of the land varies between neighborhoods and even between blocks, the truth is that in 48 cities examined, the team found The average sinking rate is 16.2 mm per year. They came to check cases that have land sinking at a rate of 43 mm per year.

Results It has been published in the scientific journal Nature Sustainability.

Where are the fastest cities sinking?

48 cities were selected based on A . criteria The minimum population is five million In 2020, the Maximum distance of 50 km from the coast.

A comparison by researchers of coastal cities around the world showed that the fastest relative decline rates of local land concentrated in Asia, Especially in Southeast Asia.

The researchers chose to use InSAR because it provides Accurate measurements of the sinking coast A tenth of a millimeter.

Ensar draws the distortion of the earth Using radar images of the Earth’s surface collected from orbiting satellites.

The data sets obtained are larger and more accurate, because, unlike visible or infrared light, used radar waves By INSAR penetrate most of the meteorological clouds and They are equally effective in the dark.

Our study highlights the fact that while this is a global problem, in many cases the response must be local. Reducing the rate of groundwater extraction to a sustainable level “It should be a priority for all municipalities in coastal areas,” said Eric Lindsey, co-author of the study and assistant professor in the Department of Earth and Planetary Sciences at the University of New Mexico in the US.

The researchers hope to expand the research by projecting Earth’s subsidence rates, taking into account differences in various climate and weather scenarios.