WASHINGTON (AP) — An iceberg twice the size of Manhattan tore off one of
Greenland’s largest glaciers, illustrating another dramatic change to the
For several years, scientists had been watching a long crack near the tip of
the northerly Petermann Glacier. On Monday, NASA satellites showed it had
broken completely, freeing an iceberg measuring 46 square miles.
A massive ice sheet covers about four-fifths of Greenland. Petermann Glacier
is mostly on land, but a segment sticks out over water like a frozen tongue,
and that’s where the break occurred.
The same glacier spawned an iceberg twice that size two years ago. Together,
the breaks made a large change that’s got the attention of researchers.
“It’s dramatic. It’s disturbing,” said University of Delaware professor
Andreas Muenchow, who was one of the first researchers to notice the break.
“We have data for 150 years and we see changes that we have not seen
“It’s one of the manifestations that Greenland is changing very fast,” he
Researchers suspect global warming is to blame, but can’t prove it
conclusively yet. Glaciers do calve icebergs naturally, but what’s happened
in the last three years to Petermann is unprecedented, Muenchow and other
“This is not part of natural variations anymore,” said NASA glaciologist
Eric Rignot, who camped on Petermann 10 years ago.
Ohio State University ice scientist Ian Howat said there is still a chance
it could be normal calving, like losing a fingernail that has grown too
long, but any further loss would show it’s not natural: “We’re still in the
phase of scratching our heads and figuring out how big a deal this really
Many of Greenland’s southern glaciers have been melting at an unusually
rapid pace. The Petermann break brings large ice loss much farther north
than in the past, said Ted Scambos, lead scientist at the National Snow and
Ice Data Center in Boulder, Colo.
If it continues, and more of the Petermann is lost, the melting would push
up sea levels, he said. The ice lost so far was already floating, so the
breaks don’t add to global sea levels.
Northern Greenland and Canada have been warming five times faster than the
average global temperature, Muenchow said. Temperatures have increased there
by about 4 degrees Fahrenheit in the last 30 years, Scambos said.
The new iceberg is likely to follow the path of the one in 2010, Muenchow
said. That broke apart into smaller icebergs headed north, then west and
last year started landing in Newfoundland, he said.
It’s more than glaciers in Greenland that are melting. Scientists also
reported this week that the Arctic had the largest sea ice loss on record
National Snow and Ice Data Center: