Study Finds Human-Caused Sea Level Rise Increased Likelihood of Extreme Coastal Floods

A study published in the journal Nature Climate Change found that floods historically expected once every 100 years are now occurring about 12 times more often on average at coastal sites worldwide. Researchers examined tide gauge records from more than 100 locations spanning 1900 to 2005 along with climate models.

They determined that human-caused warming became the dominant driver of sea level rise after the 1960s.

The analysis focused on extreme sea level events caused by the combination of rising seas, high tides, and storm surges. Lead author Sönke Dangendorf of Tulane University said greenhouse gas emissions from burning fossil fuels are the primary factor behind the changes.

A separate study in Science Advances reached similar conclusions, finding that climate change accounted for about 58% of days with major coastal floods between 2000 and 2018. That research also reported the number of days exceeding extreme flood levels nearly tripled on average since the 1970s.

Strauss of Climate Central, a co-author of the Science Advances study, said every coastal flood today carries a human influence through climate change. U.S. Geological Survey oceanographer not involved in the studies, said planners must account for these increasing threats when designing coastal protection.

Dangendorf said communities need to prepare for growing risks. Williams noted that current protections in places such as New Orleans will likely require upgrades within the next couple of decades.