Sea level rise has been speeding-up faster than previously estimated over the last three decades, said a new analysis by a Harvard-led research team. 

Prior to the onset of more sophisticated satellites, GPS and other geolocation technologies in the 1990s, measuring changes in global sea levels relied heavily on tidal gauges emplaced along coastlines.

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In this new study, researchers wanted to use if the old tide gauge data to determine how sea levels changed due to runoffs from melting glaciers on land and from thermal expansion due to absorption of heat by the ocean, among other factors, said study lead author, Carling Hay, a Harvard geophysicist.

Climate and data scientists thus reanalyzed tide gauge data using algorithms that factored in local inaccuracies and other inconsistencies. As a result, they found sea level rise from 1900 to 1990 was higher by as much as 30 percent.

They came to a conclusion of 1.6 to 1.9 millimeters a year for sea rise except for the 1990s. The new study suggests the historical rise was closer to 1.2 millimeters per year based on data from 622 tide gauges.

The same analysis, however, suggests sea level rise has been underestimated since 1990.

"What this paper shows is that sea-level acceleration over the past century has been greater than had been estimated by others," said earth and planetary scientist Eric Morrow. "It's a larger problem than we initially thought."

The new findings were published in the journal Nature.

Tagssea level rise, global warming