The Gulf Stream (shown in red) (Photo : NASA)
An exhaustive study using a millennia's worth of data has concluded the Gulf Stream is at its weakest in 1,000 years, a phenomenon that could have severe negative impacts in the eastern United States and northwestern Europe.
It said the melting ice from the Antarctic is slowing down and weakening the Gulf Stream with an influx of freshwater lighter in weight. The result could be changes in weather and higher sea levels in the eastern parts of the U.S.
"If the slowdown of the Atlantic overturning continues, the impacts might be substantial," said Stefan Rahmstorf, study author and researcher at Germany's Potsdam Institute for Climate Impact Research to UPI.
"Disturbing the circulation will likely have a negative effect on the ocean ecosystem, and thereby fisheries and the associated livelihoods of many people in coastal areas. A slowdown also adds to the regional sea-level rise affecting cities like New York and Boston."
The Gulf Stream is a powerful, warm, and swift Atlantic Ocean current that originates at the tip of Florida and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean.
Differences in density and temperature plus surface winds and weather patterns drive the Gulf Stream that pushes warm surface water northward and pulls deep cold water southward. The Gulf Stream moderates Europe's temperatures and weather systems.
The Gulf Stream is the most important ocean-current system in the northern hemisphere, which stretches from Florida to northwestern Europe.
The latest research into the Gulf Stream, however, supports previous studies that suggest overturning has slowed abruptly over the last several decades.
Researchers said the findings suggest the current slowdown is the most dramatic in recorded history but is also well outside the norm -- enough to suggest it's not part of natural fluctuation.
"There is more than a 99 per cent probability that this slowdown is unique over the period we looked at since 900 AD," said Rahmstorf.
"We conclude that the slowdown many have described is in fact already underway and it is outside of any natural variation."
Researchers believe the Gulf Stream slow down is being influenced by changes in water densities caused by the influx of fresh water from melting glaciers in the Antarctic.
"Now freshwater coming off the Greenland ice sheet is likely disturbing the circulation," said co-author Jason Box, a researcher with the Geological Survey of Denmark and Greenland.
"So the human-caused mass loss of the Greenland ice sheet appears to be slowing down the Atlantic overturning, and this effect might increase if temperatures are allowed to rise further."
