How rapidly ice sheets can disintegrate is one of the most uncertain and imporant climate issues. Disintegration of the West Antarctic ice sheet ( that portion of the Antarctic ice sheet lying in the western hemisphere) initiates a chain of events which culminates in a global ice age. ( ) report from observed fast grounding- line retreat , " it was speculated, thinning of a glacier in Pine Island Bay ( Rignot 1998; Shepherd et al. How can the answer be improved? 24640 Issued in May NBER Program( s) : Environment Energy Economics Public Economics. Concerns about the impact on large- scale earth systems have taken center stage in the scientific and economic analysis of climate change. The West Antarctic Ice Sheet and the Thwaites Glacier.As Hillenbrand et al. The WAIS is a marine ice sheet, with much of its base grounded below sea level with ﬂoat- ing ice shelves exposed to disintegration warming subsurface ocean currents that cause basal melt ( Church et al. Most of the WAIS bedrock is below sea level due to the weight of the ice sitting on it. 3 meters global SLR, on top of other effects such as thermal expansion of sea- water ( Church et al. The WAIS disintegration became a foregone conclusion when it was discovered that the base of the sheet was separating from bedrock below; that ocean water had begun to float the ice sheet off its base. Are Antarctica' s Ice Sheets Near a Climate Tipping Point? NBER Working Paper No. But that disintegration was expected to take many centuries.
A new analysis of ice sheet instability,. As warm summer temperatures push farther south, so will the problems of melt ponding, ice shelf disintegration, and ice cliff collapse, which drive the. ice sheet, as reconstructed for the CLIMAP 18000 years B. experiment, and disintegration was allowed to proceed to completion for the 125000 B. sea- level and air- temperature boundary conditions. The collapse of the Larsen B Ice Shelf was captured in this series of images from the Moderate Resolution Imaging Spectroradiometer on NASA’ s Terra satellite between January 31 and April 13,.
ice sheet disintegration
At the start of the series, the ice shelf ( left) is tattooed with parallel lines of blue dots. The Antarctic ice sheet' s loss of mass, meanwhile, traps warmer water below the surface, eroding glaciers from underneath in a vicious circle of accelerated melting that contributes to sea level rise.