WASHINGTON (AP) -- The world's oceans are now rising far faster than they did in the past, a new study says.The study found that for much of the 20th century - until about 1990 - sea level was about 30 percent less than earlier research had figured. But that's not good news, scientists say, because about 25 years ago the seas started rising faster and the acceleration in 1990 turns out to be more dramatic than previously calculated.The current sea level rise rate - which started in 1990 - is 2.5 times faster than it was from 1900 to 1990, according to a study published Wednesday in the journal Nature. Scientists say that faster pace of sea level rise is from melting ice sheets in Greenland and West Antarctica and shrinking glaciers, triggered by man-made global warming.\We're seeing a significant acceleration in the past few decades