In a nutshell
Columbia Climate School is part of Columbia University's school of transdisciplinary climate research, a program that began in 2020. The study found that some cities are sinking at different rates in different locations or sinking in some places and rising in others, according to the report. The authors found that in 25 of the 28 cities studied, two-thirds or more of the area is sinking. The study states that about 34 million people live in the affected areas studied.
Focusing on U.S. cities with populations exceeding 600,000, the study used satellite data to map vertical land movement in grids which measured about 90 feet square, according to the study.
The breakdown
Houston is the fastest sinking city with “more than 40% of its area subsiding more than 5 millimeters (about 1/5 inch) per year, and 12% sinking at twice that rate,” according to the study.
According to the report, Fort Worth and Dallas are also seeing significant sinking rates. The report also states that localized fast-sinking zones in other places include areas around New York’s LaGuardia Airport, and parts of Las Vegas, Washington, D.C. and San Francisco.
Houston and seven other cities reportedly account for more than 60% of the people living on sinking land, and the eight cities have seen more than 90 significant floods since 2000, according to the report. The other cities are New York, Chicago, Los Angeles, Phoenix, Philadelphia, San Antonio and Dallas.
The takeaway
The report recommends cities should use this new information to focus on solutions.
In many places, flooding can be mitigated with the following, according to the study results:
- Land raising
- Enhanced drainage systems
- Green infrastructure such as artificial wetlands to absorb floodwaters
- Tetrofitting existing structures
- Integrating land motions into building codes
- Limiting new building in the areas of most threat
View the report here.
