Sea levels are rising several times faster than they have over the last 2,800 years, according to new studies by international scientists. Improved techniques have been used to chart the rise due to global warming.
Studies published Monday in the journal "Proceedings of the National Academy of Sciences" said that by 2100 the world's oceans could rise between 28 to 131 centimeters (11 to 52 inches), depending on how much heat-trapping gas is expelled by industry and vehicles.
An international team of scientists dug into two dozen locations around the world to chart rising and falling seas over centuries and millennia.
Until the 1880s when industrialization began, the limit of the rise was about 3 to 4 centimeters a century. But in the 20th century the world's seas rose by 14 centimeters, and since 1993 the rate has risen to 30 centimeters per century.
"There's no question that the 20th century is the fastest," said Bob Kopp, associate director at the Rutgers Energy Institute and lead author of the study. "It's because of the temperature increase in the 20th century which has been driven by fossil fuel use."
The researchers, from institutions in the US, Europe and Asia, found that less than half of the observed sea level rise in the 20th century would have occurred without global warming.
Greenhouse gas projections
Study co-author Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research in Germany said if the seas continue to rise there will be problems and expenses, especially with storm surge.
If greenhouse gas pollution continues at the current pace, the studies project increases of about 57 to 131 centimeters. If countries fulfill the treaty agreed at last year's Paris climate summit and limit further warming to another 2 degrees Celsius (3.6 degrees Fahrenheit), then the sea level rise would be in the range of 28 to 56 centimeters.
The studies are the first to use so many regional sea level rise reconstructions and modern tide gauge data, along with other techniques, to identify the human fingerprint from about 3,000 years of sea level rise.
jm/cmk (AP, Rutgers Energy Institute)