Sea levels rose about 14 centimeters in the past century, faster than during the previous 27 centuries, due to man-made global warming, a group of scientists has said in an alarming report.

Global sea levels rose by about 14 centimeters, or 5.5 inches, from 1900 to 2000, the scientists said in a latest report, adding that without global warming, global sea level would have risen by less than half the observed 20th century increase.

"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," he added.

Notably, the study found that global sea level declined by about eight centimeters [three inches] from 1000 to 1400, a period when the planet cooled by about 0.2 degrees Celsius.
"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 higher than it was in the late 19th century, he added.