REWRITING ICE DYNAMICS: IT'S ALL ABOUT THE WATER

Recent ice sheet behavior is surprising everybody—most especially the supposed experts. Accelerating and thinning outlet glaciers and disintegrating ice shelves illustrate an underappreciation of major forcing factors and interactions now dictating the ice sheet's response to warming climate. Water is an integral player in most of the new thinking. Whether delivered through surface meltwater, or through circulating ocean waters, water accelerates ice both by providing lubrication and by delivering heat to melt and soften the ice. And if that were not enough, water movement beneath ice sheets is now becoming recognized as a far more dynamic system than previously held. Accurate predictions of future ice sheet behavior are urgently needed, but there are some radical revisions of ice sheet models that must be made first to include water's multi-faceted influences.