Sea level rose about 14 centimetres or 5.5 inches from 1900 to 2000, the fastest in 3,000 years, according to a study led by Rutgers University. The study, published in Proceedings of the National Academy of Sciences on Feb. 22, also state that the future sea level depends on climate change responses, projecting that the global sea level will increase up to 1.7 to 4.3 feet in the 21st century.

The researchers say that the increase was mostly man-made and would have been lower if it weren’t for global warming. Apparently, stopping the use of fossil fuels would only make the sea rise between 0.8 and two feet. In the year 1000 to 1400, when the Earth cooled about 0.2 degrees Celsius, the global sea level declined by eight centimetres.

Arnon Polin

Arnon Polin

“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,” explains lead author Robert Kopp, who is also an associate professor in Rutgers’ Department of Earth and Planetary Sciences. “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.”

The researchers compiled a database of records of worldwide of sea level signifiers from marshes, coral atolls, and archaeological sites as old as 3,000 years. Kopp says that they reconstructed how sea level changed at a specific area and calculated how temperatures influence sea levels.

A previous study claimed that the Greenland ice sheet, which has been known as a sponge for glacial meltwater, is quickly losing the ability to prevent sea level rise. The study was published in the journal Nature and showed that meltwater will cause the global sea level to rise higher than previously thought.