A wide, cold section of the North Atlantic – dubbed a cold “blob” by scientists studying temperature percentiles – is sticking around, leaving researchers and climatologists puzzled as to why, during a time when the rest of the world is seeing higher than normal temps, a wide area of the Atlantic remains shockingly cold.
Reports CNN on Sept. 30: “At first glance, it stands out like a sore thumb. That blob of blue and purple on the map. One of the only places on the globe that is abnormally cold in a year that will likely shatter records as the warmest globally. It’s being called the Atlantic ‘blob.’ It’s a large area in the North Atlantic that is seeing a pronounced cooling trend.”
The Atlantic anomaly is located close to Greenland. It made its appearance on temperature maps and real time ocean readings a few years ago. The blob however never dissipated. In fact, it stands in sharp contrast to record high temperatures along the same latitude lines elsewhere in the northern Atlantic and Pacific oceans.
The overall warming has been attributed to the El Nino effect – a swath of warm ocean water over the Central Pacific that extends down to South America. Global weather patterns have been impacted as the warming seas are changing the heat index in the atmosphere, causing severe droughts in many areas, with heavy flooding in others. In fact, Time predicts that ten million may go hungry over the next year due to droughts linked to rising global temperatures.
But those predictions only underscore the peculiarity of the North Atlantic “blob.” One explanation, as reported in a study by Michael Mann of Penn State and Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research, is that ocean currents may be slowing down.
“Maps of temperature trends over the twentieth century show a conspicuous region of cooling in the northern Atlantic. Here we present multiple lines of evidence suggesting that this cooling may be due to a reduction in the Atlantic Meridional Overturning Circulation (AMOC) over the twentieth century and particularly after 1970,” the study abstract reports.
The AMOC – an important component relating to our globe’s climate – is a major current in the Atlantic Ocean, characterized by a “northward flow of warm, salty water in the upper layers of the Atlantic, and a southward flow of colder water in the deep Atlantic,” says The Encyclopedia of Earth.
“This circulation pattern is tied to the productivity of the North Atlantic, one of the most productive regions from a fisheries standpoint. So if the AMOC were literally to shut down, you could see sharp decreases in marine productivity in this region,” Mann said.
Another potential explanation for the cold blob is that the accelerated melting of Greenland’s 20,000-square mile ice sheet is slowly adding record amounts of frigid water to the North Atlantic. If the sheet were to melt completely, scientists estimate ocean levels would rise by a disastrous 20 feet. Recent studies estimate the ice sheet is melting at a rate of somewhere between 40 and 60 cubic miles per year.
“A slowdown in current also adds to the regional sea-level rise affecting cities like New York and Boston,” professor Rahmstorf said. “Finally, temperature changes in that region can also influence weather systems on both sides of the Atlantic, in North America as well as Europe.”