Rutgers University Study finds sea level rise in the 20th Century was fastest in 3,000 years
Global sea level rose faster in the 20th century than in any of the 27 previous centuries, according to a Rutgers University-led study published today.
Moreover, without global warming, global sea level would have risen by less than half the observed 20th century increase and might even have fallen.
Instead, global sea level rose by about 14 centimeters, or 5.5 inches, from 1900 to 2000. That’s a substantial increase, especially for vulnerable, low-lying coastal areas.
“The 20th-century rise was extraordinary in the context of the last three millennia – and the rise over the last two decades has been even faster,” said Robert Kopp, the lead author and an associate professor in Rutgers’ Department of Earth and Planetary Sciences.
The study, published in Proceedings of the National Academy of Sciences, used a new statistical approach developed over the last two and a half years by Kopp, his postdoctoral associates Carling Hay and Eric Morrow, and Jerry Mitrovica, a professor at Harvard University.
“No local record measures global sea level,” Kopp said. “Each measures sea level at a particular location, where it is buffeted by a variety of processes that cause it to differ from the global mean. The statistical challenge is to pull out the global signal. That’s what our statistical approach allows us to do.”
Notably, the study found that global sea level declined by about 8 centimeters [3 inches] from 1000 to 1400, a period when the planet cooled by about 0.2 degrees Celsius [0.4 degrees Fahrenheit].
“It is striking that we see this sea-level change associated with this slight global cooling,” Kopp said. By comparison, global average temperature today is about 1 degrees Celsius [1.8 degrees Fahrenheit] higher than it was in the late 19th century.
A statistical analysis can only be as good as the data it’s built upon. For this study, a team led by Andrew Kemp, an assistant professor of earth and ocean sciences at Tufts University, and Benjamin Horton, a professor in Rutgers’ Department of Marine and Coastal Sciences, compiled a new database of geological sea-level indicators from marshes, coral atolls and archaeological sites that spanned the last 3,000 years.
Dead tree in seawater image via Shutterstock.
Read more at Rutgers University.