Some scientists are worried about a surprisingly cold ‘blob’ in the North Atlantic Ocean
A patch of the Atlantic Ocean, south of Greenland and Iceland, has experienced unusually cold temperatures for the last eight months and a number of prominent climate scientists say it’s the result of Greenland’s melting glaciers dumping fresh water in the ocean. They also say it is ruining the Atlantic’s circulation.
When NOAA released its report on the first seven months of 2015, the map of the globe was almost completely covered in red to signify that most of the planet was experiencing above-average temperatures for the year.
But there was one big chunk of the North Atlantic Ocean that was a deep, dark blue. Some saw the below-average temperatures of that region as the lone silver lining on the entire map while others questioned why that area was having its coldest year on record.
As the Washington Post points out, those readings are almost assuredly accurate; NOAA’s National Centers for Environmental Information confirmed it. The message that came next from some climate scientists was a quick reminder that this cold “blob” is probably not good news.
Some experts theorize that the cold water south of Iceland shows the Atlantic Ocean’s circulation is slowing, according to a study published in the journal Nature Climate Change. In short, warm and cold water should work together to balance out the temperature of the oceans, Inhabitat said. Cold, salty water should be pushed down below the surface, and warm water should rise up to replace it. Likewise, the warm salt water should move north with the current, and cold water should go south.
But the massive ice melt occurring in the Arctic has introduced a lot of cold, fresh water into the mix, and it’s not behaving the same as cold salt water. It’s preventing the sinking that usually happens with cold water, as fresh water is less dense than salt water, and that could be weakening the circulation.
“The fact that a record-hot planet Earth coincides with a record-cold northern Atlantic is quite stunning,” Stefan Rahmstorf, one of the authors of the study published in Nature Climate Change, told the Washington Post. “There is strong evidence — not just from our study — that this is a consequence of the long-term decline of the Gulf Stream System, i.e. the Atlantic ocean’s overturning circulation AMOC (Atlantic Meridional Overturning Circulation), in response to global warming.”
Rahmstorf also told the Washington Post he doesn’t expect the blob to remain at record cold levels indefinitely, though the circulation should continue to decline. Everything is connected, and climate scientists believe that connection will drive temperatures, and sea levels, higher and higher.