A large ice island has broken off the Petermann Glacier in northern Greenland.

NASA satellite image (MODIS).

This iceberg is about twice the size of Manhattan but approximately half the size of the previous recent break-off in 2010 (blog post here).  Unlike the 2010 event the current ice has broke off further up glacier and marks a retreat of the calving front of the glacier.  The crack and rift that led to this break off has been known and observed for some time and so this event was expected in this regards.  However, the question is still being asked as to how unusual these large calving events are and whether they were caused by climate change.  Certainly we can say that these changes have not been seen for at least a 150 years (see previous post and this discussion article).  However, we can’t say for certain that these two massive calving event are a direct result of climate change.  An interesting discussion on these questions is provided in this BBC article.

The Guardian has a little interactive page where you can watch the iceberg break off in context (click here).

Glaciologist Tim Creyts provides an insightful radio interview here.

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This is a photo of the Petermann Ice Island taken by a NASA International Space Station crew.   This amazing image reveals the ice island complete with melt ponds and supraglacial meltwater channels clearly visible.

A series of close-up photos of this huge ice chunk taken in August 2011 can be viewed here.  Currently the ice island is located off the coast of Newfoundland, as seen in July from this satellite image, and reported in this CBC new article.

Updates on the progress of the ice island can be tracked from the Environment Canada webpage.

The drifting ice island originated from the Petermann Glacier in Northwest Greenland breaking off as a giant iceberg of unprecedented size (five times the size of Manhattan Island) on August 5, 2010 (see satellite images here).  The Petermann Glacier drains about 6% of the Greenland ice sheet.  Previously this ice-front had a relatively stable position, but recent environmental changes raise questions about the possible further retreat of the ice-tongue and the knock-on contributions to sea-level rise.  See this article for more context and scientific insight.

K. K. Falkner, H. Melling, A. M. Munchow, J. E. Box, T. Wohlleben, H. L. Johnson, P. Gudmandsen, R. Samelson, L. Copland, K. Steffen, E. Rignot, and A. K. Higgins.  Context for the Recent Massive Petermann Glacier Calving Event, EOS, 92, 117-124, 2011.

Another major iceberg is poised to break off again from Petermann Glacier, probably next year now, according to Glaciologist Jason Box (see media reports here and here).