There is much wailing and gnashing of teeth.
The headlines would suggest an impending catastrophe. The Western Atlantic ice sheet is “collapsing”. Sea level could rise 1.2m.
The end of the world is nigh. And it is all due to global warming!!
Yes indeed – except that the melting has been going on for centuries. The so called “collapse” may take upto 1,000 years! Measurements over 9 years are projected over a millenium. Computer models have forecast that the loss of the glaciers is unstoppable and will occur sometime in the next 1,000 years.
The Guardian: Western Antarctic ice sheet collapse has already begun, scientists warn
BBC: ‘Nothing can stop retreat’ of West Antarctic glaciers
A collapse in very slow motion!
The alarmist headlines are are based on two papers. Note that one is based on 9 years of measurement and the other is a computer forecast about a “collapse” that is potentially underway.
1. E. Rignot, J. Mouginot, M. Morlighem, H. Seroussi and B. Scheuchl, Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith and Kohler glaciers, West Antarctica from 1992 to 2011, Geophysical Research Letters, DOI: 10.1002/2014GL060140
Abstract: We measure the grounding line retreat of glaciers draining the Amundsen Sea Embayment of West Antarctica using Earth Remote Sensing (ERS-1/2) satellite radar interferometry from 1992 to 2011. Pine Island Glacier retreated 31 km at its center, with most retreat in 2005–2009 when the glacier un-grounded from its ice plain. Thwaites Glacier retreated 14 km along its fast-flow core and 1 to 9 km along the sides. Haynes Glacier retreated 10 km along its flanks. Smith/Kohler glaciers retreated the most, 35 km along its ice plain, and its ice shelf pinning points are vanishing. These rapid retreats proceed along regions of retrograde bed elevation mapped at a high spatial resolution using a mass conservation technique (MC) that removes residual ambiguities from prior mappings. Upstream of the 2011 grounding line positions, we find no major bed obstacle that would prevent the glaciers from further retreat and draw down the entire basin.
2. Ian Joughin, Benjamin E. Smith and Brooke Medley, Marine Ice Sheet Collapse Potentially Underway for the Thwaites Glacier Basin, West Antarctica, Science, DOI: 10.1126/science.1249055
Abstract: Resting atop a deep marine basin, the West Antarctic Ice Sheet has long been considered prone to instability. Using a numerical model, we investigate the sensitivity of Thwaites Glacier to ocean melt and whether unstable retreat is already underway. Our model reproduces observed losses when forced with ocean melt comparable to estimates. Simulated losses are moderate (<0.25 mm per year sea level) over the 21st Century, but generally increase thereafter. Except possibly for the lowest-melt scenario, the simulations indicate early-stage collapse has begun. Less certain is the timescale, with onset of rapid (> 1 mm per year of sea-level rise) collapse for the different simulations within the range of two to nine centuries.
The Antarctic glaciers may well be retreating (as glaciers are often wont to do), but Antarctic ice cover is at an all time high and the processes being forecast are being projected over millenia. And there is absolutely no evidence that these processes have anything whatever to do with any man-made effects. That connection is inferred or assumed.
Related: The Guardian’s Suzanne Goldenberg jumps the shark again – gets called out by NYT
The k2p blog 