History of Antarctic glacier melt suggests more to come

A glacier on the West Antarctic Ice Sheet, already the largest single source of global sea level rise, may keep thinning for decades, scientists say. A team of British, American and German geologists say they've determined the Pine Island Glacier (PIG) -- which is rapidly accelerating, thinning and retreating -- has done so rapidly before, suggesting the potential for current ice loss could be ongoing for several decades yet. Their study showed the glacier thinned as fast 8,000 years ago as it has in recent decades, providing an important model for its future behavior, the British Antarctic Survey reported Thursday. Highly sensitive dating techniques used to track the thinning of the glacier through time show the past thinning lasted for several decades. "Our geological data show us the history of Pine Island Glacier in greater detail than ever before," study lead author Joanne Johnson of the BAS said. "The fact that it thinned so rapidly in the past demonstrates how sensitive it is to environmental change; small changes can produce dramatic and long-lasting results." After two decades of rapid ice loss, there is concern about how much more ice will be lost to the ocean in the future, the researchers said. "Based on what we know, we can expect the rapid ice loss to continue for a long time yet, especially if ocean-driven melting of the ice shelf in front of Pine Island Glacier continues at current rates," Johnson said.