Scientists have discovered that much of Greenland's ice sheet is melting at an unusually rapid pace:

Scientists said the "unprecedented" melting took place over a larger area than has been detected in three decades of satellite observation. [...] The thawed ice area jumped from 40% of the ice sheet to 97% in just four days from 8 July.

Although about half of Greenland's ice sheet normally sees surface melting over the summer months, the speed and scale of this year's thaw surprised scientists, who described the phenomenon as "extraordinary".

Scientists also reported that much of the ice is re-freezing, so they remain puzzled as to the reason for the unusual thaw. Link