Apologies to those readers bored by stories about ice. While there has been a continual stream of stories about the extent of sea ice in the Arctic, there has been rather less about the overall volume of frozen water up there in the cold north.

A recent paper from Geophysical Research Letters addresses ice-geek cravings in this area. In this paper Katharine Giles and colleagues from the UK’s National Centre for Earth Observation use satellite radar data to assess average sea ice thickness. The researchers say that during the 2007/08 winter average ice thickness was 26 cm below the average thickness of the past six years.

“The ice thickness was fairly constant for the five winters before this, but it plummeted in the winter after the 2007 minimum,” Giles told the BBC.

Co-author Seymour Laxon adds, “To determine whether the reduction in sea ice extent is the result of ice being piled up against the coast or whether it is the result of melting, you need to measure the thickness. I think this is the first time that we can definitively say that the bulk overall volume of ice has decreased.”

The Daily Telegraph notes:

Before this latest study, Christian Haas of the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, had discovered thinner ice in a small region around the North Pole but this is the first time scientists have been able to show that the ice thinning was widespread and occurred in areas of both young and old ice.

In the Guardian Vicky Pope, of the UK Met Office, cautions that these changes might not necessarily be down to climate change. “There’s clearly a decline over the last 30 years and we can detect a human signal in that, but the change in the last couple of years could be due to natural fluctuations in the weather,” she says.

Image: NOAA