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CMIP5 Models Attempting to Replicate Antarctic Sea Ice Trends

Paper Reviewed
Bintanja, R., Van Oldenborgh, G.J. and Katsman, C.A. 2015. The effect of increased freshwater from Antarctic ice shelves on future trends in Antarctic sea ice. Annals of Glaciology 56: 120-126.

In their intriguing new paper on Antarctic sea ice trends -- which are positive -- Bintanja et al. (2015) investigate "to what extent future sea-ice trends are influenced by projected increases in Antarctic freshwater flux due to subsurface melt, using a state-of-the-art global climate model (EC-Earth) in standardized Climate Model Intercomparison Project phase 5 (CMIP5) climate-change simulations." And what did they thereby learn?

The three Dutch researchers first of all report that (1) "virtually all CMIP5 models disregard ocean-ice-sheet interactions and project strongly retreating Antarctic sea ice," which is just the opposite of what is actually occurring there. However, they report that by "applying various freshwater flux scenarios," one of which includes subsurface ice melt, they found that (2) "the additional fresh water significantly offsets the decline in sea-ice area and is even able to reverse the trend in the strongest freshwater forcing scenario that can reasonably be expected." And they say that (3) "the model also simulates decreasing sea surface temperatures (SSTs), with the SST trends exhibiting strong regional variations that largely correspond to regional sea-ice trends."

Posted 11 March 2016