Greenland Slipping into the Sea

Or rather the ice upon it:

But her team also found that, when considered over the whole year, the surface meltwater was responsible for only a few per cent of the movement of the glaciers that they monitored. Even at its peak, it appeared to contribute only 15%, and often less, to the annual movement of the outlet glaciers at the edge of Greenland.

"Considered together, the new findings indicate that while surface melt plays a substantial role in ice sheet dynamics, it may not produce large instabilities leading to sea level rise," says Ian Joughin, a glaciologist at the University of Washington. "There are still other mechanisms that are contributing to the current ice loss and likely will increase this loss as climate warms."

"To influence flow, you have to change the conditions underneath the ice sheet, because what\’s going on beneath the ice dictates how quickly the ice is flowing," said Das. "If the ice sheet is frozen to the bedrock or has very little water available, then it will flow much more slowly than if it has a lubricating and pressurised layer of water underneath to reduce friction … It\’s hard to envision how a trickle or a pool of meltwater from the surface could cut through thick, cold ice all the way to the bed. For that reason, there has been a debate in the scientific community as to whether such processes could exist, even though some theoretical work has hypothesised this for decades."

So we\’re back to the idea that it will melt, but not the catastrophic and immediate slipping of all the ice into the ocean. Back, in fact, to the 2500, 2700 AD timescale for that sea level rise which we think will occur.

Whatever discount rate you use (and whatever growth rate to the economy you apply) it\’s really rather difficult to construct a case that we should do something now to prevent that happening then.

For example, using the 3% or so global growth rate, in 2500 those people extant then will be more than 2 million times richer than us. At 2%, 17,000 times richer.

They can deal with it themselves.

3 comments on “Greenland Slipping into the Sea

  1. And they are only referring to “outlet glaciers” the central ice sheet is not going anywhere as it sits in a bowl and may have been gaining mass.

  2. Does not compute.

    The melting/freezing point of H2O is zero C at atmospheric pressure, but it is much lower at higher pressures (like the famous physics experiment where a wire from which a heavy block is suspended cuts through a block of ice which re-freezes behind it).

    If the ice is thick enough then the pressure at the bottom is so huge that there will be water there however bloody cold it is.

    Although if it is in a bowl, that’s neither here nor there. Well, it’s ‘there’ actually.

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