A recent study reveals that 25 US cities are threatened by flooding, and Houston could disappear entirely.

 An expression of cities being submerged due to climate change

Land subsidence is a growing danger exacerbated by climate change and urban population growth.

Twenty-five US cities, along with many others worldwide, face the risk of being submerged. Among them is the renowned and historic city of Houston, which a recent study concludes could officially be declared submerged and disappear from the world within a few years. According to the study, published in the British newspaper the Financial Times, global climate change could lead to the disappearance of these 25 US cities, submerging them beneath the sea.

The study concluded that "the problem of land subsidence not only affects coastal areas, where sea levels are rising due to climate change, but also inland communities. Groundwater extraction hollows out subsurface sediments, while urban development adds further weight on top, resulting in a slow, gradual slide of the land."

 Global warming – Illustrative image 

This landslide can weaken vital infrastructure, including buildings, bridges, and sewage systems; reduce the ability of aquifers to retain water; increase the risk of flooding; and create large sinkholes. The new findings of this study reinforce the need to take land subsidence seriously, a risk exacerbated by climate change and population growth in urban areas. 

Just because land subsidence is occurring slowly does not mean it should be ignored. Radar satellites can be used to measure land elevation by sending microwave pulses toward the Earth and measuring the time it takes for the echoes to return.

Leonard Ohnin, from the Lamont-Doherty Earth Observatory at Columbia University, collaborated with researchers, mostly from Virginia Tech, to examine data from the Sentinel-1 satellite collected between 2015 and 2021. 

By comparing seismic readings taken at different times over the 28 most populous cities in the United States, researchers were able to calculate the amount of ground movement, either up or down. Their study revealed that 25 cities showed, on average, subsidence rather than uplift.

Expression of climate change 

Land subsidence is a growing threat exacerbated by climate change and urban population growth.

Among the U.S. cities facing subsidence and sinking, Texas cities of Houston, Fort Worth, and Dallas fared the worst, showing an average subsidence of more than 4 mm per year. 

Due to drought and poor water management, parts of Tehran are sinking by up to 31 cm annually; cracks are appearing in roads, World Heritage sites, and the airport. The current Iranian president has even floated the idea of ​​relocating the capital, which faces a chronic and persistent water shortage.

While some parts of Houston are sinking by more than 10 mm per year, this seems insignificant compared to other severely flooded cities like Jakarta and Tehran. Indonesia has built a new capital, Nusantara, partly due to Jakarta's continued subsidence of up to 15 centimeters per year. About half of Jakarta—home to 11 million people—now lies below sea level.

A Financial Times report, citing a scientific study, says China is a deteriorating hotspot, with nearly half of its cities, including Beijing, sinking. Mexico City is another capital city on the slide. A 2024 paper estimated that nearly two billion people worldwide live in areas affected by subsidence, calling it a "sinking crisis."

Current warming is exacerbating the risks. Melting permafrost is causing subsidence in Alaska; rising sea levels are combining with land subsidence to make flooding more frequent; and climate-induced droughts are increasing the demand for water, further destabilizing the region.