New photographs taken of a vast glacier in northern Greenland have revealed the astonishing rate of its breakup, with one scientist saying he was rendered ‘speechless.’

In August 2010, part of the Petermann Glacier about four times the size of Manhattan island broke off , prompting a hearing in Congress.

Researcher Alun Hubbard, of the Centre for Glaciology at Aberystwyth University, U.K., told msnbc.com by phone that another section, about twice the size of Manhattan, appeared close to breaking off.

In 2009, scientists installed GPS masts on the glacier to track its movement.

But when they returned in July this year, they found the ice had been melting so quickly – at an unexpected 16-and-a-half feet in two years – that some of the masts stuck into the glacier were no longer in position.

Hubbard, who has been working with Jason Box, of Ohio State University, and others, said in a statement issued by the Byrd Polar Research Center that scientists were still trying to work out how fast the glacier was moving and the effect on the ice sheet feeding the glacier.

‘Although I knew what to expect in terms of ice loss from satellite imagery, I was still completely unprepared for the gob-smacking scale […]