It just rained on the summit of Greenland’s ice sheet, marking yet another alarming milestone in our ecological unravelling.
Greenland has been experiencing a heatwave, with temperatures at its summit exceeding freezing, just like the rest of the Northern Hemisphere. The National Snow and Ice Data Center (NSIDC), Summit Station, recorded rain for several hours on 14 August 2021 at a location that is normally too cold for water to drop as a liquid.
"There has never been any rainfall reported at this elevation, which reaches 3,216 metres (10,551 feet)." NSIDC reported. Noting that the daily average for this season is seven times greater, the NSIDC noted that the amount of ice that was lost in one day was seven-fold higher than the daily average.
On August 14, 2021, temperatures rose above freezing on the summit of Greenland, fueling a rain event that dumped 7 billion tons of waterthe heaviest since records began in 1950. pic.twitter.com/EyTDhS80f5 National Snow and Ice Data Center (@NSIDC) August 18, 2021
The Washington Post was informed by Ted Scambos, University of Colorado Boulder glaciologist. "Greenland is changing like the rest of world," he said. "We now see three melting episodes in a decade here in Greenland. Before 1990, this happened approximately once in 150 years. Now, rain is falling in an area that has never seen it.
"Like the heat wave that hit the [US Pacific] northwest, it is something that is hard to imagine without global climate change."
In areas that don't usually see summer melt, ice sheets can form. Over thousands of years, winter snow accumulates and compresses under the weight of new layers.
Warm air temperatures have caused melts in the past. This has led to growing networks of summer lakes, which can accelerate melting and destabilize ice sheets.
Rain melts snow and contributes to increased melting events. It also has the potential to alter long-term ice sheet dynamics.
Rain exposes and freezes a layer that is darker than the normal white, packed-snow glacier ice. It will form a barrier that prevents meltwater from leaking below the surface once it has frozen. This can cause more melting at higher elevations than usual runoff impacts.
Lauren Andrews, NASA glaciologist, said that melt events can happen over areas of the ice sheets that don't typically see melt. This makes the impact greater across the globe. These positive feedbacks are beginning to show their effects.
Yesterday's heavy rains caused massive melt to occur today on the Greenland Ice Sheet. This is 7x higher than normal and represents the highest level of melting since 1950 (the peak for Mid-August). The temperature is still extremely high. pic.twitter.com/A0vHINgAAH Xavier Fettweis (@xavierfettweis) August 15, 2021
The Greenland Ice Sheet is home to enough freshwater to raise sea levels 6 meters (20 feet) and has a significant impact on weather and climate. According to the IPCC, a temperature increase of more than 2 degrees Celsius will cause the melting of this huge ice sheet. This is a tipping point scientists are extremely concerned about.
The loss of ice is causing problems for the local indigenous communities. Wildlife and other wildlife also are experiencing these changes. In addition to the direct effects on sea level rise, melting Greenland ice is predicted to slow the Gulf Stream ocean current. This would affect patterns of tropical monsoons and impact rainforests.
Scambos stated to CNN that "We are crossing thresholds never seen in millennia" and that this will not change until CNN adjusts what it does to the air.
It will take many of us to work together around the world to hold those responsible accountable and help each other make better collective decisions.
