image: Woodley Wonder Works/Creative Commons
Some more hows and whys to the what of the fact that the Greenland Ice Sheet is melting, and should it disappear completely there's 7 meters of sea level rise at the end of it all: New research published in Nature details how the ice sheet can adapt each year and drain off the increasing amounts of meltwater created by warming temperatures.Study lead author Professor Andrew Shepherd of the University of Leeds explains,
It had been though that more surface melting would cause the ice sheet to speed up and retreat faster, but our study suggests that the opposite could in fact be true. If that's the case, increases in surface melting expected over the 21st century may have no affect on the rate of ice loss through flow. However, this doesn't mean that the ice sheet safe from climate change, because the impact of ocean-driven melting remains uncertain. (Science Daily)
Based on satellite observations of land-locked glaciers in Greenland, the team discovered that though there was a quickening of ice sheet movement in all years, in the warmest ones a slowdown of movement occurred more quickly. In these years it's speculated that the extra meltwater in those warm years triggers a pressure drop at the base of the ice, reducing the speed of ice movement.
Read the original research: Melt-induced speed-up of Greenland ice sheet offset by efficient subglacial drainage
Combine this was some research published in December, which showed that the Greenland Ice Sheet is more able to accommodate gradual warming than it can short-term extreme weather events.
The conventional view has been that meltwater permeates the ice from the surface and pools under the based on the ice sheet. This water then serves as a lubricant between the glacier and the earth underneath it, allowing the glacier to shift to lower, warmer altitudes where more melt would occur. Sudden water input caused by short term extremes, such as massive rain storms of the draining of a surface lake, however...allows [the meltwater] to pool and lubricate the bottom of the glaciers and accelerate ice loss.
Remember that both gradual warming and more volatile and extreme weather are both caused by climate change.
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More on Greenland:
Greenland Ice Sheet Melt Caused By Short-Term Extreme Weather Not Gradual Temperature Rise
Greenland Glacier About To Lose Manhattan-Sized Ice Chunk (Video)
Two Meter Sea Level Rise Now Inevitable - But How Fast Will It Happen?