Watts Up With That?

Above image is not part of original papers, but included to demonstrate the issue. Animation of Arctic sea-ice being pushed by wind patterns. Note that the animation is large, about 7 MB and may take awhile to load on your computer. Source: National Snow and Ice Data Center

From Climate Research News

Two new studies summarized in a news article in Science magazine point to wind-induced circulation changes in the ocean as the dominant cause of the recent ice losses through the glaciers draining both the Greenland and West Antarctic ice sheets, not ‘global warming.’

The two stuides referred to are:

‘Acceleration of Jakobshavn Isbræ triggered by warm subsurface ocean waters’ by Holland et al, published in Nature Geoscience.

The Abstract states:

Observations over the past decades show a rapid acceleration of several outlet glaciers in Greenland and Antarctica¹. One of the largest changes is a sudden switch of Jakobshavn Isbræ, a large outlet glacier feeding a deep-ocean fjord on Greenland’s west coast, from slow thickening to rapid thinning² in 1997, associated with a doubling in glacier velocity³. Suggested explanations for the speed-up of Jakobshavn Isbræ include increased lubrication of the ice-bedrock interface as more meltwater has drained to the glacier bed during recent warmer summers⁴ and weakening and break-up of the floating ice tongue that buttressed the glacier⁵. Here we present hydrographic data that show a sudden increase in subsurface ocean temperature in 1997 along the entire west coast of Greenland, suggesting that the changes in Jakobshavn Isbræ were instead triggered by the arrival of relatively warm water originating from the Irminger Sea near Iceland. We trace these oceanic changes back to changes in the atmospheric circulation in the North Atlantic region. We conclude that the prediction of future rapid dynamic responses of other outlet glaciers to climate change will require an improved understanding of the effect of changes in regional ocean and atmosphere circulation on the delivery of warm subsurface waters to the periphery of the ice sheets.

And: Read the rest of this entry »