A team of scientists is warning that the double whammy of a naturally recurring weather pattern and rising temperatures is triggering dramatic melting on the Greenland ice sheet—a problem the researchers liken to recent global coral bleaching events, which have been fuelled by the one-two punch of El Niño and climate change.
Over the course of a decade, the scientists documented a four-fold acceleration in the mass of ice lost across Greenland, from 102 billion tonnes a year in 2003 to 393 billion tonnes a year in 2013.
Then, all of a sudden, something caused Greenland to press pause.
That something, the researchers say, was the North Atlantic Oscillation (NAO)—a natural atmospheric cycle that influences weather across a wide region as it oscillates between positive and negative.
Positive phases of the NAO bring cooler-than-average temperatures to Greenland, while negative phases are associated with warmer summers and less snowfall, particularly in west Greenland.
From 2003 to 2013, the NAO veered more and more negative, a trend the researchers found mapped closely to a speed-up in the amount of meltwater flowing off southwest Greenland.