Rising Sea Levels Amplify Coastal Flooding Risks

Extreme floods that were once rare on coastlines are now increasingly common. Human-induced climate change is pushing sea levels higher, according to recent research released on Wednesday. Experts emphasize that this information is vital for planning flood protections and coastal infrastructure as global temperatures rise.

Coastal floods occur when high tides and storm surges combine with rising sea levels. This happens in conjunction with natural climate patterns and other human influences. Climate change intensifies storms, such as Hurricane Ian, which led to major flooding in 2022. Annually, floods threaten hundreds of millions of people in low-lying coastal regions worldwide, causing deadly consequences and inflicting billions of dollars in damage.

Recent studies show that floods with a historically 1% annual chance of hitting coastlines are now around 12 times more likely. Human-driven climate change alone makes these events four times more frequent. This new study, found in the journal Nature Climate Change, was published on Wednesday. Researchers examined extreme sea level events using data from over 100 tide gauge sites and climate modeling, focusing on the period from 1900 to 2005. The research indicates today’s risks may be understated as human contributions to coastal changes have intensified since 2005.

“Essentially every coastal flood today has human fingerprints on it through climate change,” remarked Ben Strauss, chief scientist at Climate Central.

Researchers differentiated changes caused by human actions, natural forces, or landscape shifts. Earlier in the 20th century, natural forces mainly accounted for sea level changes. Nevertheless, since the 1960s, human-induced warming has become the primary driver, resulting in rising sea levels.

A separate study in Science Advances reveals that about 58% of big flood days from 2000 to 2018 relate to climate change. Since the 1970s, climate change nearly tripled the number of days with extreme sea levels. Sönke Dangendorf, the lead author, noted the significant role of greenhouse gases from fossil fuels since the 1970s.

Dangendorf warns about the growing threat and the need for communities to prepare. Jeff Williams, a retired oceanographer, highlighted the importance of considering these threats in planning and funding coastal protection measures.

Global efforts to switch to renewable energy have been increasing. In 2022, clean power generation exceeded overall electricity demand growth for the first time, with renewables forming more than a third of the global electricity mix. Although the U.S. has favored fossil fuels, solar energy continues to grow as coal declines. While scientists affirm the world is steering away from the worst warming scenarios, challenges remain in achieving the best outcomes.

Dangendorf concluded, “The impacts of even a small sea level rise can be significant on our coasts. We have control over our emissions, so we can mitigate these developments to some extent.”