After going two years with summer ice melt being minimal, the year 2019 shattered all records when the Greenland ice sheet lost 586 billion tons (532 billion metric tons) of ice, based on satellite measurements reported in a study published Thursday in Nature Communications Earth & Environment.
That is more than double the yearly average loss of 235 billion tons since 2003, and easily passes the old record set in 2012.
“Not only is the Greenland ice sheet melting, but it’s melting at a faster and faster pace,” said study lead author Ingo Sasgen, a geoscientist at the Alfred Wegener Institute in Germany, according to CBC Canada.
Last year’s Greenland melt added 0.06 inches (1.5 millimeters) to global sea level rise. That sounds like a tiny amount but “in our world it’s huge, that’s astounding,” said study co-author Alex Gardner, a NASA ice scientist.
Gardner explained that if we add the water from other ice sheets as they melt, along with the water from melting glaciers and the expansion of oceans as they warm, this all translates into slowly rising sea levels, coastal flooding and other problems.
While records on Greenland’s ice sheet date back to 1948, it has only been since 2003 that scientists have been able to compile precise records on the amount of ice melt. This is because NASA satellites actually measure the gravity of the ice sheets. That’s the equivalent of “putting the ice on a scale and weighing it as water flows off,” Gardner said.
The two years preceding 2019’s record ice melt saw on average about 108 billion tons (98 billion metric tons) of ice loss. According to Gardner, this shows that there’s a second factor called Greenland blocking, that either super-charges or dampens climate-related melting,
A Greenland block occurs when atmospheric pressure builds over Greenland and forces the jet stream to dip into eastern North America. Greenland blocks develop in the far Northern Atlantic, in the vicinity of Greenland or Iceland. This can happen when storms pump warm air northward, quite often pushing the jet stream south.
Greenland Blocks can occur in the summer, such as the Greenland block that formed in July 2012. The temperatures in Greenland got so warm that it caused the most extensive melting of the Greenland ice sheet in recorded history at that time. It appears that summer Greenland block patterns are becoming more extreme.
Many climate scientists agree with Sasgen’s calculations, saying they make sense. “The fact that 2019 set an all-time record is very concerning,” said New York University ice scientist David Holland, who wasn’t part of the study, reports Phys.org.
