Key facts
- Human-driven sea level rise has increased the frequency of extreme coastal flooding globally.
- Extreme sea level events that had a 1% chance of occurring annually are now about 12 times more likely.
- Human-caused climate change is responsible for approximately four times the increased likelihood of these events.
- A separate study indicates climate change is linked to 58% of extreme water level days between 2000 and 2018.
- Human-caused warming has been the dominant factor in sea level rise since the 1960s.
Human-driven sea level rise has significantly amplified the occurrence of extreme coastal flooding worldwide, according to a study published in Nature Climate Change. The research indicates that events with a 1% annual chance of happening are now, on average, 12 times more likely, with human-induced climate change accounting for about four times this increase.
The study analyzed long-term tide gauge records from over 100 locations and utilized climate modeling from 1900 to 2005. While natural forces were primary drivers of sea level changes earlier in the 20th century, human-caused warming has been the dominant factor since the 1960s. The authors noted that their findings are conservative, as human contributions to coastal extremes have continued to grow.
A concurrent study in Science Advances found that climate change was responsible for 58% of extreme water level days between 2000 and 2018, nearly tripling the number of such days since the 1970s. Ben Strauss of Climate Central stated that "essentially every coastal flood today has human fingerprints on it through climate change," adding that most events would not have reached flood status without the additional sea level rise from global heating.
Sönke Dangendorf, the lead author of the Nature Climate Change study, identified greenhouse gases from burning fossil fuels as the most significant contributor, particularly since the 1970s. He emphasized the need for increased adaptation measures. Jeff Williams, a retired USGS oceanographer, advised that planners must account for these heightened risks and consider the costs and funding for enhanced coastal protection, citing New Orleans' current defenses as potentially inadequate for the coming decades.