In NASA’s annual summary of global temperature rise, a field of warming reds and yellows is broken by a persistent cold blue spot in the North Atlantic.
Learn what explains that anomaly.
A stubborn blue spot of cool ocean temperatures stands out like the proverbial sore thumb in a recent NASA image of the warming world – a circle of cool blue on a planet increasingly shaded in hot red.
A region of the North Atlantic south of Greenland has experienced some of its coldest temperatures on record in recent years, a cooling unprecedented in the past thousand years.
What Explains That North Atlantic Temperature Anomaly?
Climatologist Michael Mann of Penn State University explains that this phenomenon may be an indication that the North Atlantic current, part of a larger global ocean circulation, is slowing down.
This circulation – called the thermohaline circulation, but popularly known to many in the U.S. as “the Gulf Stream” – keeps northern Europe several degrees warmer than it would otherwise be at that latitude.
The current depends on the saltiness of the North Atlantic to create the sinking motion of water, that is, it’s the “pump” driving the current. Saltier water is heavier than fresh water.
As the Greenland ice sheet melts, large volumes of fresh water enter the North Atlantic and freshen the very salty sea water, slowing the “pump.”
“We are 50 to a hundred years ahead of schedule with the slowdown of this ocean circulation pattern, relative to the models,” according to Mann. “The more observations we get, the more sophisticated our models become, the more we’re learning that things can happen faster, and with a greater magnitude, than we predicted just years ago.”
The consequences of a shutdown would be serious for agriculture – and for temperate weather – in northern Europe. Another sigh we are heading to a complete economic and societal collapse. [Yale Climate Connection]