Climate Change Nearly Triples Extreme Water Level Days
Climate change was responsible for 58% of observed extreme water-level days from 2000 to 2018, Climate Central research finds.
Climate Central found human-caused sea level rise is detectable at 97% of 519 tide gauge sites investigated worldwide, and that climate change was responsible for 58% of observed days with extreme water levels from 2000 to 2018. Averaged across all locations, climate change nearly tripled the number of days exceeding extreme water-level thresholds since the 1970s. The research, published in Science Advances, assesses the human contribution to sea level rise and extreme water levels at local and regional scales. It draws on sea-level records from 1900 through 2018.
Two Methods Measure Sea Level Rise
Researchers used two largely independent methods to estimate the climate change signal in sea level rise and extreme water levels. The first calculated attributable sea level rise from thermal expansion of water, melt from mountain glaciers, and ice loss from the Greenland and Antarctica ice sheets.
The second compared observed sea levels over 1900 to 2018 with a modeled scenario for the same period without climate-warming pollution. The methods reached similar conclusions, supporting the finding that human-caused sea level rise is responsible for driving the majority of extreme water levels worldwide.
Daniel Gilford, paper author and climate scientist at Climate Central, said:
“These studies highlight how we've loaded the climate dice against not only our children and grandchildren, but ourselves! The effects of human-caused climate change are already here. We will continue to face growing threats like increasing coastal flood risks unless we immediately and sharply reduce our climate pollution.”
Related Study Examines Coastal Extremes
The findings were released alongside a complementary paper from Tulane University in Nature Climate Change, titled “Human-driven sea-level rise has quadrupled the frequency of coastal sea-level extremes since 1900.”
Both studies were co-supported by the Megalopolitan Coastal Transformation Hub, a National Science Foundation-funded, Rutgers-led consortium focused on advancing the science of coastal climate risk and the practice of coastal climate adaptation.
Robert Kopp, a Distinguished Professor in the Department of Earth and Planetary Sciences and Director of the Megalopolitan Coastal Transformation Hub at Rutgers University and a co-author of the Science Advances study, said:
“Sea level rise is making both tidal flooding and storm-driven flooding more frequent, extensive and expensive. Together, these two studies allow us to pinpoint the human role in driving these changes.”
Local Evidence For Coastal Risk
The 519-site analysis provides a global assessment of how human-caused climate change has affected sea level rise and days with extreme water levels. Its results identify a measurable climate change signal across the large majority of the tide gauge locations investigated.
