SUBJECT :Climate Change 
Climate change over the last few years has altered the structure of the Greenland ice sheet, causing it to lose its ability to limit mass loss of ice by retaining melt-water, a new study has found.

It is rapidly losing the ability to buffer its contribution to rising sea levels. Researchers spent five weeks in 2013 drilling firn cores in the interior of the ice sheet. Firn is multi-year compacted snow that is not as dense as glacier ice.

Instead, it forms a porous near-surface layer over the ice sheet.

Researchers found that an extreme melt that occurred in 2012 caused a layer of solid ice to form on top of the porous firn in the low elevation areas of the ice sheet. "In subsequent years, melt-water couldn't penetrate vertically through the solid ice layer, and instead drained along the ice sheet surface towards the ocean," said a researcher.

Source: January 6, 2016, The Economic Times