© from NASA |
© Steve Nerem |
The team observed a total rise in the ocean of 7 centimeters (2.8 inches) in 25 years of data, which aligns with the generally accepted current rate of sea level rise of about 3 millimeters (0.1 inches) per year.
But that rate is not constant.
Continuous emissions of greenhouse gases are warming the Earth's atmosphere and oceans and melting its ice, causing the rate of sea level rise to increase.
© Joe Raedle/Getty Images North America/Getty Images |
Greenland's melting glaciers may someday flood your city
That projection agrees perfectly with climate models used in the latest International Panel on Climate Change report, which show sea level rise to be between 52 and 98 centimeters by 2100 for a "business as usual" scenario (in which greenhouse emissions continue without reduction).
Therefore, scientists now have observed evidence validating climate model projections, as well as providing policy-makers with a "data-driven assessment of sea level change that does not depend on the climate models," Nerem said.
© NASA |
Consider the record set in Boston Harbor during January's "bomb cyclone" or the inundation regularly experienced in Miami during the King tides; these are occurring with sea levels that have risen about a foot in the past 100 years.
Now, researchers say we could add another 2 feet by the end of this century.
Nerem and his team took into account natural changes in sea level thanks to cycles such as El Niño/La Niña and even events such as the 1991 eruption of Mount Pinatubo, which altered sea levels worldwide for several years.
The result is a "climate-change-driven" acceleration: the amount the sea levels are rising because of the warming caused by manmade global warming.
The researchers used data from other scientific missions such as GRACE, the Gravity Recovery and Climate Experiment, to determine what was causing the rate to accelerate.
Currently, over half of the observed rise is the result of "thermal expansion": As ocean water warms, it expands, and sea levels rise. The rest of the rise is the result of melted ice in Greenland and Antarctica and mountain glaciers flowing into the oceans.
Theirs is a troubling finding when considering the recent rapid ice loss in the ice sheets.
"Sixty-five centimeters is probably on the low end for 2100," Nerem said, "since it assumes the rate and acceleration we have seen over the last 25 years continues for the next 82 years."
"We are already seeing signs of ice sheet instability in Greenland and Antarctica, so if they experience rapid changes, then we would likely see more than 65 centimeters of sea level rise by 2100."
Penn State climate scientist Michael Mann, who was not involved with the study, said "it confirms what we have long feared: that the sooner-than-expected ice loss from the west Antarctic and Greenland ice sheets is leading to acceleration in sea level rise sooner than was projected."
Links
- Satellites show warming is accelerating sea level rise
- Swallowed By The Sea
- Sea Levels Are Already Rising. What's Next?
- For Scientists Predicting Sea Level Rise, Wind Is The Biggest Unknown
- Coal Use Must 'Pretty Much' Be Gone By 2050 To Curb Sea-Level Rise, Researchers Say
- 25 Years Of Global Sea Level Data, And Counting
- Are The Floating Houses Of The Netherlands A Solution Against The Rising Seas?
- Climate Change Will Almost Certainly Heat The World So Much It Can Never Recover, Major Study Finds
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