Sea levels will rise much faster than previously forecast because of the rate that glaciers and ice sheets are melting, a study has found.

Research commissioned by the US Climate Change Science Program concludes that the rises will substantially exceed forecasts that do not take into account the latest data and observations.

The adjusted outlook, announced at a meeting of the American Geophysical Union in San Francisco, suggests that recent predictions of a rise of between 7in and 2ft over the next century are conservative.

The study predicts that sea level rises will be far higher than the levels that were set out last year by the Inter-governmental Panel on Climate Change. The research looked at prehistoric periods when the climate changed dramatically over the course of decades, and evaluated the mechanisms behind such rapid transformation. Rising sea levels were one of the major elements involved in past episodes, along with faster glacial melting, droughts and changes to the Atlantic Ocean’s heat-driven circulation.

The report also concludes that some changes will not be as bad as first thought. It says, for example, that rapid releases of methane stored in permafrost and on the seabed may be less likely than feared.Other forecasts include a severe and permanent drought in the American West. The authors state that they are “among the greatest natural hazards facing the United States and the globe today” and call for “committed and sustained” monitoring of the forces that could trigger abrupt climate change.

Peter Clark, a professor of geosciences at Oregon State University and a lead author on the report, to be published in the journal Science, said: “If we don’t monitor the vital signs of the patient, then we’ll never be in a position to advise on the best course of action to take to ward off or prepare for the potentially devastating consequences.”

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