By Claire

The large iceberg that broke free from the Petermann Glacier on Monday.

Just a few days ago, a glacier twice the size of Sydney Harbour broke off from the Petermann Glacier in Greenland.

While it is a natural phenomenon for icebergs to break (or calve) off from large glaciers that flow in to the ocean, it is the size and frequency of events that is concerning to glaciologists.

“This is not part of natural variations anymore,” said NASA glaciologist Eric Rignot, referring to the vast changes the glacier has seen in the past three years.

The same glacier calved a much larger iceberg, twice the size of this current one and one of the largest ever recorded in Greenland, in 2010.

Left: the new ice island. Right: the ice island that calved from Petermann Glacier in 2010. The crack that led to the 2012 calving also is clearly visible

It is important to note that the tail of the glacier flows into the ocean, meaning that this latest iceberg was already in the water prior to calving off and so is not expected to contribute to sea level rise.

Given that satellite observations over Greenland are a relatively new technology, it is not possible to say definitively if these large calving events form part of a trend.

What we do know for sure is that temperatures over Greenland are warming at twice the global rate, the Greenland ice sheet has experienced increasing mass loss over the last century, and arctic sea ice extent and thickness continues to decline.

While there can be no single ‘indicator’ of climate change, the increase in indicators that it may be occurring now can not and should not be ignored.

Find out more here.