One scientist says he is "gob-smacked" by the extent of the breakup of a Greenland glacier in just the last two years.
Located in north west Greenland, the Petermann Glacier accounts for 6% of the area of the Greenland ice sheet, said Dr Hubbard. It terminates as a floating tongue of ice, measuring around 43 miles (70km) long by 12 miles (20km) wide, the largest of its kind in the northern hemisphere. At its thickest the glacier is 3,280ft (1000m) high. "Although I knew what to expect in terms of ice loss from satellite imagery, I was still completely unprepared for the gob-smacking scale of the break-up, which rendered me speechless," said Dr Hubbard. "It was incredible to see. This glacier is huge, 20km across and 1000m high. "It's like looking into the Grand Canyon full of ice and coming back two years later to find it's full of water."