Global sea-level rise is one of the greatest challenges of climate change. And for the more than half a billion people living in low-lying coastal areas, this threat is even greater.
According to a new study by researchers at the Technical University of Munich and Tulane University, people living in densely populated coastal regions experience a relative sea-level rise of about six millimeters per year, which is nearly three times the global coastal average. The research, which was recently published in the journal Nature Communications, found that this amplified rise is caused by sinking land, a process known as land subsidence.
According to the research team, groundwater extraction, oil and gas production, compacting sediments, and the growing weight of cities can all cause land to sink. Natural forces, including tectonic activity and the slow adjustment of land following the last Ice Age, can also play a role.
Some cities are particularly vulnerable. Jakarta, Tianjin, Bangkok, Lagos, and Alexandria are all experiencing substantial subsidence. In parts of Jakarta, land is sinking by as much as 42 millimeters per year!
But the researchers say there is reason for some optimism. In some regions, managing groundwater withdrawals has significantly reduced subsidence. Tokyo once experienced sinking rates exceeding ten centimeters per year, but government action and alternative water supplies dramatically slowed the process.
Protecting coastal communities isn’t just about slowing climate change. It’s also about understanding and managing the land beneath our feet.
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References:
Sea levels rising dramatically in some areas due to land subsidence
Subsidence more than doubles sea-level rise today along densely populated coasts
