NASA satellite images reveal a phenomenon has occurred in Greenland this month, showing melting activity on nearly all parts of the island's massive ice sheet.
The Associated Press called this a "freak" event. NASA calls it "unprecedented." Others have used words like "alarming pace," "extreme rate," and "massive" to describe the melt.
Although some of these descriptions aren't entirely untrue, even within NASA's own announcement of this observation, a Goddard Space Flight Center scientist said these types of melting events occur every 150 years, on average.
With the last event happening in 1889, Lora Koening said "this event is right on time."
She does note that if strong melting events like this continue in future years, "it will be worrisome."
NASA says three satellites saw the melting over four days beginning July 8. Most of the thick ice remains. But what is technically unusual about this event is that the melting occurred over a widespread area.
NASA says the melting area went from 40 percent of the ice sheet to 97 percent. Until now, the most extensive melt seen by satellites in the past 30 years was about 55 percent over the summer months.
As AP puts it, scientists can't say yet if the melting is from global warming or natural.
"The Greenland ice sheet is a vast area with a varied history of change. This event, combined with other natural but uncommon phenomena, such as the large calving event last week on Petermann Glacier, are part of a complex story," said Tom Wagner, NASA's cryosphere program manager, in a statement. "Satellite observations are helping us understand how events like these may relate to one another as well as to the broader climate system."
The Associated Press contributed to this report.