A new peer-reviewed study by climate scientists finds the rise in sea level during the past two decades has been 60 percent faster than predictions from the United Nation's Intergovernmental Panel on Climate Change.
The scientists also found that IPCC's estimates for warming temperatures was just right.
"'Global warming has not slowed down or is lagging behind the projections,' lead author Stefan Rahmstorf, a researcher at Germany's Potsdam Institute for Climate Impact Research, said in a statement. 'The IPCC is far from being alarmist and in fact in some cases rather underestimates possible risks.'
"The experts added that the faster sea level rise is unlikely to be caused by a temporary ice discharge from Greenland or Antarctica ice sheets because it correlates very well with the increase in global temperature.
"The IPCC earlier estimated that seas rose by about 7 inches over the last century, and its most recent report, published in 2007, estimated a range of between 7 and 23 inches this century enough to worsen coastal flooding and erosion during storm surges."
The scientists published the research in today's edition of the journal Environmental Research Letters and it comes at the same time as 194 countries meet in Qatar for another round of U.N. climate talks.
The Guardian reports that a separate study published last March, looked at especially vulnerable areas in the world.
The paper writes:
"It singled out the California cities of Los Angeles and San Diego on the Pacific coast and Jacksonville, Florida, and Savannah, Georgia, on the Atlantic, as the most vulnerable to historic flooding due to sea-level rise.
"Sandy, which produced a 9ft storm surge at Battery Park in New York City, produced one example of the dangerous combination of storm surges and rising sea level. In New York, each additional foot of water puts up to 100,000 additional people at risk, according to a map published with the study.
"But tens of millions of people are potentially at risk across the country. The same report noted that more than half of the population, in some 285 US cities and towns, lived less than 1m above the high tide mark."
One scientist told the paper that means it wouldn't take much for a once in a century storm to become a once in a decade storm.