No equal to recent Greenland melt in centuries-long ice core

Staring down the barrel of an ice core drill.

Enlarge / Staring down the
barrel of an ice core drill. (credit: Sarah Das / WHOI)

The Greenland Ice Sheet’s unhealthy and rapid weight
loss—and contribution to sea level rise—occurs by a handful of
mechanisms. In short, ice at the edge of the glacier can melt or
break off into icebergs, and surface snow farther inland can melt.
That snow melt is a bit like rainfall, in that it can either soak
into the snow or runoff in streams.

Where it trickles down into the denser snow beneath, it
refreezes and forms a stubborn layer that will continue to be
visible when that snow is compressed into glacial ice. That means
that drilling an ice core can give you a record of past surface
melting events.

Greenland has experienced a remarkable amount of surface melting
over the past couple decades, including the record-setting summer
of 2012 that saw virtually the entire ice sheet melting at the
surface. Because surface melting had historically been an unusual
event akin to newsworthy heat wave, glaciologists wanted to put
this into context. How much of Greenland’s recently accelerating
ice loss was due to natural variability, and how much was due to
human-caused trends?

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Source: FS – All – Science – News
No equal to recent Greenland melt in centuries-long ice core