Coastal cities around the world are facing a hidden but urgent threat, land subsidence. As urban populations grow and groundwater extraction increases, many cities are sinking faster than sea levels are rising.
A recent satellite-based study published in Nature Sustainability ranked 48 major coastal cities based on their rate of land sinking, measured in millimeters per year. The results are alarming, with some cities sinking at rates over 40 mm annually.
In this article, we highlight the 10 fastest-sinking coastal cities worldwide, including one from the U.S., revealing the growing risk these urban areas face from subsidence and rising seas.
Here are the 10 Fastest Sinking Coastal Cities Worldwide:
1: Tianjin, China
Tianjin holds the leading position on this global list of the fastest-sinking coastal cities. The study, featured in Nature Sustainability and utilizing satellite radar, measured the rate of land subsidence in millimeters per year.
Tianjin’s peak velocity was recorded at a significant 43 mm per year. Its median velocity is 6 mm per year.
The ranking is based on the peak velocity, making Tianjin the city with one of the most aggressive rates among those studied. This rapid rate of land sinkage poses a pressing issue for the city and its residents.
2: Ho Chi Minh City, Vietnam
Ranked as the second fastest-sinking coastal city globally is Ho Chi Minh City, Vietnam. This position is based on the analysis of land subsidence rates in 48 major coastal cities using satellite radar.
The study measured both peak velocity and median velocity in millimeters per year. Ho Chi Minh City has a peak velocity of 43 mm per year, matching Tianjin’s highest rate.
Its median velocity is 16 mm per year. The ranking is determined by the peak velocity. As one of the ten cities at highest risk, Ho Chi Minh City faces significant challenges from this rapid rate of land sinkage.
3: Chittagong, Bangladesh
Chittagong, Bangladesh, ranks third on this list of the world’s fastest-sinking coastal cities. The study used satellite radar to determine land subsidence rates in millimeters per year for 48 major coastal cities.
The two metrics are peak velocity and median velocity, with peak velocity being used for ranking. Chittagong’s peak velocity was measured at 37 mm per year.
Its median velocity is 12 mm per year. This rate places Chittagong among the top cities experiencing rapid land sinking, highlighting a significant and pressing issue for its urban area.
4: Yangon, Myanmar
Yangon, Myanmar, is the fourth city listed among the fastest-sinking coastal cities worldwide. The study, utilizing satellite radar technology, assessed land subsidence rates in 48 major coastal cities, reporting measurements in millimeters per year.
Both peak velocity and median velocity were recorded. Yangon’s peak velocity is 31 mm per year. Its median velocity is 4 mm per year.
The ranking of these cities is determined by their peak velocity. Yangon’s inclusion in the top ten underscores the pressing issue of rapid land sinkage affecting certain coastal urban populations.
5: Jakarta, Indonesia
Jakarta, Indonesia, holds the fifth position on this global list of fastest-sinking coastal cities.
Based on the study featured by Mindfully American, which used satellite radar to analyze 48 major coastal cities, land subsidence rates were determined.
The metrics used were peak velocity and median velocity in millimeters per year, with peak velocity determining the rank. Jakarta’s peak velocity is 26 mm per year.
Its median velocity is 5 mm per year. This rate places Jakarta among the ten cities facing the highest risk of fast land sinking.
6: Ahmedabad, India
Ahmedabad, India, is ranked as the sixth fastest-sinking coastal city on this global list. The study employed satellite radar to measure land subsidence rates across 48 major coastal cities, recording both peak and median velocity in millimeters per year.
The rankings presented here are based on the peak velocity measurement. Ahmedabad’s peak velocity was reported as 23 mm per year.
Its median velocity is 5 mm per year. This rate signifies a significant level of land sinkage, making it a pressing issue for the city.
7: Istanbul, Turkey
Istanbul, Turkey, ranks seventh on this global list of the fastest-sinking coastal cities. The study featured in Nature Sustainability used satellite radar to measure land subsidence rates in 48 major coastal cities, focusing on peak and median velocity in millimeters per year. The city rankings are based on peak velocity. Istanbul’s peak velocity is 19 mm per year. Its median velocity is 6 mm per year. As one of the ten cities facing the most aggressive rates of land sinkage globally, Istanbul confronts significant challenges.
8: Houston, United States
At number eight on this global list is Houston, United States. It is the only U.S. city included in this specific top ten ranking of the world’s fastest-sinking coastal cities.
The study used satellite radar to measure land subsidence rates, distinguishing between peak and median velocity in millimeters per year.
Houston’s peak velocity is 17 mm per year. Its median velocity is 3 mm per year. While Houston is the sole U.S. representative on this particular global list, the source indicates that many other areas in the U.S. also suffer from land subsidence.
9: Lagos, Nigeria
Lagos, Nigeria, is ranked as the ninth fastest-sinking coastal city globally. The study, using satellite radar to analyze 48 major coastal cities, determined land subsidence rates in millimeters per year.
The metrics utilized were peak velocity and median velocity, with the ranking based on peak velocity.
Lagos shares a peak velocity of 17 mm per year with Houston and Manila. Its median velocity is 2 mm per year.
Lagos’s inclusion highlights the widespread nature of rapid land sinkage as a pressing issue for coastal urban areas worldwide.
10: Manila, Philippines
Rounding out the top ten fastest-sinking coastal cities globally is Manila, Philippines. Based on the study’s data, which measured land subsidence rates in 48 major coastal cities using satellite radar, Manila’s sinking rate was determined.
The study focused on peak velocity and median velocity, with peak velocity used for the ranking. Manila’s peak velocity is 17 mm per year, the same rate recorded for Houston and Lagos. Its median velocity is 2 mm per year.
Manila’s presence on this list underscores the significant global challenge posed by land subsidence in vulnerable coastal regions.
Alicia Richards