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Researchers warn that the impact of rising sea levels on large cities such as San Francisco and New Orleans in the United States could be more severe than expected by mid-century as coastal land is sinking.
The researchers found that even with current coastal defense infrastructure, land subsidence and sea-level rise could put more than 1,300 square kilometres of new land at risk of flooding over the next 30 years, affecting more than 50,000 to 270,000 people and more than 170,000 properties.
According to research published Wednesday (March 6) in the journal Nature Science, global warming is causing ice sheets and glaciers to melt and cause sea levels around the world, showing that the United States will become one of the fastest-rising countries with sea levels, which will threaten the coastal areas where the three mouths of the United States are located.
Sea levels are expected to rise by about 30 centimeters in coastal areas of the United States by 2050, significantly increasing the risk of devastating climate impacts such as storm surges.
To slow the rate of subsidence, the researchers recommend reducing groundwater extraction, regulating industrial activities, and reducing emissions to reduce long-term climate risks. Seawalls, river embankments, and barriers provide flood protection, while nature-based solutions such as restoring swamps and mangroves can help.
But the study found that the threat is even greater if coastal subsidence is taken into account. Researchers warn that tens of thousands of people in 32 cities along the Atlantic, Pacific and Gulf coasts, as well as potentially billions of dollars' worth of property, could be exposed. Poor and minority communities are most at risk.