This story was originally published by Yale Environment 360 and is reproduced here as part of the Climate Desk collaboration.
In August 2021, rain fell atop the 10,551-foot summit of the Greenland ice cap, triggering an epic meltdown and a more than 2,000-foot retreat of the snow line. The unprecedented event reminded Joel Harper, a University of Montana glaciologist who works on the Greenland ice sheet, of a strange anomaly in his data, one that suggested that in 2008 it might have rained much later in the season — in the fall, when the region is typically in deep freeze and dark for almost 24 hours a day.
When Harper and his colleagues closely examined the measurements they’d collected from sensors on the ice sheet those many years ago, they were astonished. Not only had it rained, but it had rained for four days as the air temperature rose by 30 degrees Celsius (54 degrees Fahrenheit), close to and above the freezing point. It had warmed the summit’s firn layer — snow that is in transition to becoming ice — by between 11 and 42 degrees F (6 and 2... Read more
