Earth has been particularly hot in 2015, as the planet has experienced its highest ever recorded surface temperatures in the first eight months of the year, dating back all the way to 1880. The National Oceanic and Atmospheric Administration (NOAA) says that this year will break records for all-time high temperatures.
However, while most of Earth is unusually hot, there is one spot of the planet that is going against this trend. An area in the North Atlantic Ocean just south of Greenland and Iceland has been noticeably colder than usual. This region has even experienced record cold temperatures.
Scientists believe that this phenomenon has been caused by the slowing of the circulation of the Atlantic Ocean.
Last March, several climate specialists such as Stefan Rahmstorf of Potsdam and Michael Mann of Penn State published a research paper that stated that the major ocean current, the Atlantic Meridional Overturning Circulation (AMOC) has been weakening. The AMOC is often confused with the “Gulf Stream” current, but that is just the southern part of the current.
The current exists because of differences in temperature and salt content of the ocean water. Cold water with a high salt content sinks since it is denser. Hotter water that comes from the south moves to the north to take the place of the cold water. Along with the hot water comes a large amount of heat energy. However, a large input of cold water with a low salt content can stop this process from occurring. As a result, the circulation is weakened.
In the paper published by Rahmstorf and Mann, it is believed that a large input of cold water with a low salt content is coming from Greenland, which is rapidly melting. The icy country is losing over 100 billion tons of ice annually.
Mann said, “I was formerly somewhat sceptical about the notion that the ocean ‘conveyor belt’ circulation pattern could weaken abruptly in response to global warming. Yet this now appears to be under way, as we showed in a recent article, and as we now appear to be witnessing before our very eyes in the form of an anomalous blob of cold water in the subpolar North Atlantic.”
Rahmstorf added, “The fact that a record-hot planet Earth coincides with a record-cold northern Atlantic is quite stunning. 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, in response to global warming.”
The scientists went on to state that they don’t believe that the area will remain unusually cold permanently. However, they do expect the AMOC to continue to weaken.
Rahmstorf had discussed this trend as early as last year, as he noticed that the same North Atlantic region was unusually cold that year as well.
“The North Atlantic between Newfoundland and Ireland is practically the only region of the world that has defied global warming and even cooled,” he said at the time.
The phenomenon has only continued since then. For now, it would be wise to keep an eye on this region to see if the trend keeps going.