By Lise Alves, Contributing Reporter
MIAMI BEACH, FLORIDA – Researchers studying deposits from Artà Cave, on the island of Mallorca in the western Mediterranean Sea, have found evidence that three million years ago sea levels were as much as sixteen meters higher than they are today.
The findings may help scientists understand and predict changing coastline amid today’s global warming. Professor Bogdan Onac, from the Department of Geosciences at the University of South Florida explained the value of the new information.
“Our data indicates that the polar ice caps are very sensitive to warming and provide important calibration targets for future ice sheet models,” Onac said. “Which in turn will serve as critical input for future climate model development that will hopefully improve confidence in sea level projections.”
Professor Onac, along with other scientists from the University of New Mexico, the University of South Florida, Universitat de les Illes Balears and Columbia University, published their findings in last week’s edition of Nature.
The scientists analyzed seventy samples from geologic formations found at elevations of 22.5 to 32 meters above present sea level. Some of these samples were concluded to be dated back to 4.4 to 3.3 million years ago.
With the sixteen meter higher sea level findings millions of years ago, these researchers concluded that even if atmospheric CO2 stabilizes around current levels, the global mean sea level would still likely rise at least that high, if not higher.
“In fact, it is likely to rise higher because of the increase in the volume of the oceans due to rising temperature,” says the press release issued by the group.
Although the majority of scientists agree that sea level rises as a result of melting ice sheets, especially those located in the extremes of the globe (Greenland and Antarctica) how much and how fast sea level will rise during the warming of the planet is a question scientists have been trying to answer.
“Considering the present-day melt patterns, this extent of sea level rise would most likely be caused by a collapse of both Greenland and the West Antarctic ice sheets,” adds USF Ph.D. student Oana Dumitru, another of the researchers of the study.
According to scientists, reconstructing ice sheet and sea-level changes during past periods when climate was warmer than today will provide clues to answer these questions.
“Studying and understanding global mean sea level during past warmer periods on Earth is critical to our ability to forecast, adapt to, and lessen the effect of future global warming on humanity,” says Professor Onac.
According to the U.S. National Oceanic and Atmospheric Administration (NOAA) sea level continues to rise at a rate of about 1/8 of an inch per year.
Eight of the world’s ten largest cities are near a coast, according to the U.N. Atlas of the Oceans.
In the United States, almost forty percent of the population lives in coastal areas, where sea level plays a role in flooding, shoreline erosion, and hazards from storms, reports NOAA.
“We hope our results will be of use to modelers, glaciologists, and climate scientists in their quest to better constrain the amount of future sea-level rise caused by present global warming trend,” concludes Professor Onac.