Ice melt is changing Greenland’s coastline shape.
Rapid melt is reshaping coastal Greenland, potentially altering the human and animal ecosystems along the country’s coast. Greenland is losing 500 gigatonnes of ice each year, more than can be replenished by new snowfall. Annual ice loss is 14 per cent greater today than it was between 1985 and 1999. The meltwater is lubricating the ice sheet so that it slides more easily on its underlying bedrock, hastening the continued melt.
Researchers combined two types of data from satellite imagery: how fast the ice sheet is moving and where glaciers terminate on their path downhill. When a glacier retreats, its terminus doesn’t reach as far downvalley as it once did. They found that glacier retreat is now the norm in Greenland. Around 89 per cent of glaciers had retreated substantially within the last decade. Virtually none had advanced.
However, this reshaping of glaciers translated into a variety of changes in glacier movement. Some glaciers were speeding up, flowing more rapidly towards the sea, while others were flowing more slowly. Over several years to a decade, a single glacier could do both, depending on the topography around it.
The Kjer and Hayes glaciers in northwestern Greenland sped up at their primary outlets to the sea from the 1990s to 2010, but other ice outlets to the ocean nearby slowed down. In one case the southerly portion of one of those outlets sped up, then slowed again. There is evidence of ice channels narrowing, of rerouting meltwater paths and even of the slowing of new ice so that glaciers are stranded in place, more like lakes than rivers.
STEPHANIE PAPPAS