14 DAY TRIAL // For climate change deniers looking for a way to demonstrate that global sea level rise will not affect the world in the coming decades, we have good news and bad news. The good news is that estimates of previous sea levels were higher than in reality. The bad news is that the seas rose by 20 to 43 feet.
While this is only 67 percent of the level scientists previously estimated, it is still a monumental increase. According to investigators, Earth's shorelines looked very different than they do today around 400,000 years ago, when the planet passed through a period of extreme global warming.
At that time, sea levels were extremely high. Studies have proposed that waters were 30 to 60 feet (9 to 18 meters) higher than they are today. The new investigation, carried out on cliffs and ancient reefs on the Bermuda and Bahamas islands, reduced that estimate by 33 percent.
However, that still leaves us with a 6- to 13-meter increase 400 millennia ago. Determining the amount of sea level rise that occurred during past global warming periods is essential for modeling how the planet will react to the climate change it's currently experiencing.
Current models vary in their estimates, saying that global water levels will increase by several inches to several feet by 2100. By introducing more data in the models, scientists can potentially clear up some of the uncertainty associated with the simulations.
The Bermuda and Bahamas islands were selected as excellent places to study because their cliffs indicate the height at which ancient shorelines once stood. Details of the new investigation were published in the latest issue of the top scientific journal Nature.
“Our research provides a simple explanation for high beach deposits [such as fossils in the Bahamas],” explains Maureen Raymo, who was the lead author of the paper. She holds an appointment as a scientist at the Columbia University Lamont-Doherty Earth Observatory.
“We're re-thinking many of our estimates of past sea-level rise now that we're more aware of the effects of unloading of ice. We now have a meaningful way of calculating the rebound,” Bil Haq explains.
The expert holds an appointment as a program director with the US National Science Foundation (NSF) Division of Ocean Sciences. The DOS provided the funds necessary for this research.
“This study is a good example of collaboration between paleoceanography and geophysics to resolve an important issue: the question of future sea-level rise,” Haq concludes.
The new study clears some of the concerns experts had over the health of the East Antarctic Ice Sheet, but indicates that we should definitely be worried about the ice making up the West Antarctic Ice Sheet and Greenland.