Rain fell at the normally snowy summit of Greenland for the first time on record
For the first time on record, precipitation on Saturday at the summit of Greenland — roughly two
miles above sea level — fell as rain and not snow.
Temperatures at the Greenland summit over the weekend rose above freezing for the third time in
less than a decade. The warm air fueled an extreme rain event that dumped 7 billion tons of water
on the ice sheet, enough to fill the Reflecting Pool at the National Mall in Washington, DC,
nearly 250,000 times.
It was the heaviest rainfall on the ice sheet since record keeping began in 1950, according to
the National Snow and Ice Data Center, and the amount of ice mass lost on Sunday was seven times
higher than the daily average for this time of year.
Ted Scambos, a senior research scientist at the National Snow and Ice Data Center at the
University of Colorado, said this is evidence Greenland is warming rapidly.
"What is going on is not simply a warm decade or two in a wandering climate pattern," Scambos
told CNN. "This is unprecedented."
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The National Science Foundation's Summit Station is located at the highest point on the Greenland
ice sheet, where scientists can observe Arctic weather and changes in the ice. The station has
been staffed year-round to observe extreme changes since 1989. The majority of the weekend's rain
fell from the southeast coast of Greenland up to the Summit Station.
Jennifer Mercer, program officer for the Office of Polar Programs at the National Science
Foundation, said because of the significant rain event, operations at the Summit Station would
need to change: "It means that we need to consider weather events that we have not had to deal
with before in the history of our operations there," she told CNN.
"Increasing weather events including melting, high winds, and now rain, over the last 10 years
have occurred outside the range of what is considered normal," Mercer said. "And these seem to be
occurring more and more."
A Greenland researcher holds a thin piece of ice that formed when rain fell on top of the snow at
the Greenland summit on Saturday.
A Greenland researcher holds a thin piece of ice that formed when rain fell on top of the snow at
the Greenland summit on Saturday.
As human-caused climate change warms the planet, ice loss has rapidly increased. A major UN
climate report released this month concluded that the burning of fossil fuels led to Greenland
melting over the past two decades. A recent study published in the journal Cryosphere found Earth
has lost a staggering 28 trillion tonnes of ice since the mid-1990s, a large portion of which was
from the Arctic, including the Greenland ice sheet.
In July, the Greenland ice sheet experienced one of the most significant melting events in the
past decade, losing more than 8.5 billion tons of surface mass in a single day, which was enough
to submerge Florida in two inches of water. It was the third instance of extreme melting in the
past decade, during which time the melting has stretched farther inland than the entire satellite
era, which began in the 1970s.
In 2019, Greenland shed roughly 532 billion tons of ice into the sea. During that year, an
unexpectedly hot spring and a July heat wave caused almost the entire ice sheet's surface to
begin melting. Global sea level rose permanently by 1.5 millimeters as a result.
"We are crossing thresholds not seen in millennia, and frankly this is not going to change until
we adjust what we're doing to the air," said Scambos.
Other unusual events have become more frequent, too, Mercer said.
Two years ago, a polar bear made it to the Summit Station, which was unusual since polar bears
live in coastal regions where they can easily find food. The bear had trekked several hundred
miles inland across the ice sheet. In the last five years, Mercer said three polar bears have
been sighted high on Greenland's ice sheet.
According to Mercer, the rain will have a lasting effect on the properties of the snow, leaving a
crust of ice behind that will absorb more energy from the sun, until it gets buried by snow.
Scambos said this crusty layer will also be a barrier that prevents the downward draining of melt
water, which will then flood the surface of the ice sheet and initiate run off at higher
elevations.
Because of the layer of ice it created, the weekend's rainfall event "will be visible in ice core
records in the future," Mercer said.
CNN's Brandon Miller contributed to this report.
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