Sea levels are rising far faster than previously recorded, a new study found.

Sea level was about 30 percent less than earlier research figured for a majority of the 20th century up until 1990, the study says. This may sound great, but it is not good news. Twenty-five years ago, sea level began to rise faster, and the acceleration of the rise turned out to be far more dramatic than previously calculated, according to scientists.

A study published in the journal Nature said we are currently seeing a sea-level rise rate that is 2.5 times faster than it was from 1900 to 1990. This quickened rate can be attributed to melting ice sheets in Greenland and West Antarctica and shrinking glaciers, scientists say. The problem was triggered by manmade global warming.

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“We’re seeing a significant acceleration in the past few decades,” said study lead author Carling Hay, a geophysical researcher at Harvard University. “It’s concerning for cities along the U.S. East Coast” where water levels are rising even faster than the world average.

“It’s definitely something that can’t be ignored,” Hay said.

Previous research said that between 1900 and 1990, the seas rose about two-thirds of an inch a decade. The new study recalculates the 1900 to 1990 rate to less than half an inch a decade.

Old and new research say that since 1990 seas are rising at about 1.2 inches a decade.

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While hundreds of tide gauges around the world have been measuring sea levels since 1900, they have mostly been in Europe and North America with few in the polar regions or the middle of the oceans, Hay said. So past estimates of 20th century sea-level rise gave an incomplete picture of the global effect, said study co-author Jerry Mitrovica, a Harvard geophysics professor.

The new method uses statistical analysis and computer models to better simulate the areas in the gap, Mitrovica said.

Outside scientists praised the new studybut were still cautious about adopting the estimates until more studies could be done.

“The implications are troubling—accelerated ocean warming, ice sheet collapse and sea-level rise—all point to more and more sea level rise in the future, perhaps at a faster rate than previously thought,” said Jonathan Overpeck, co-director of the Institute of the Environment at the University of Arizona. “This will make adaptation to climate change more difficult and costly.”

MORE ON WEATHER.COM: Greenland Global Warming

Tim Elam works on deploying the Ice Diver, which if successful will melt its way through the ice with electrical heating. (Joe Raedle/Getty Images)