Thursday, September 20, 2007

Letter on Melting Glaciers

Email received from a friend of OBRL:

A fellow called Jim Belog (sp?) was on NBC News tonight, he has placed time lapse camera around Greenland and he is tracking this over a three period, his first review of the cameras which were placed in June are fairly dramatic.  You may wish to check this out.


I watched the video, which was fascinating but lacking in necessary details.  We've known for some time that the glaciers on the periphery of Greenland were no longer surging forward and hence crumbling back, as they generally have ceased their sea-wards motion from the interior sources.  If they don't move, they don't replace the eroding and melting at their toes.  So that's no surprise by itself.  Now, if the cause for the ending of the ice-surging is that the larger Greenland Ice Cap is withering away, that would be alarming news -- but my last info was that snowfall was actually increasing in the Greenland interior.  That being so, the current absence of glacial surging and meltback at the toes would suggest the current observations are capturing only part of some larger cycle of isostatic movement of glaciers -- if ice is indeed building in the interior which is the source for the coastal glaciers, then there eventually would be a restoration of surging and increasing coastal ice at some point down the line. That can happen with an atmospheric warming, actually faster than during cooling because warm air carries greater moisture and can build snowpack even more quickly.  In any case, when glaciers are on the move, they build a ring of floating ice along the shorelines.  When no longer moving, the ice crumbles into the sea.  That can occur even as there is a period of rebuilding of ice in the interior, which eventually creates new glacier motion and rebuilding of the sea ice shelves.   It is a matter of the weight-pressure of accumulated ice-mass in the glacial feed zones at higher altitudes, versus the slope of the ice sheet towards sea-level, and other friction factors which govern ice-movement over the land, and there can be a considerable lag time between accumulating ice versus glacial motion.

These cycles take place over reasonably to very long periods, decades for some mountain glaciers, hundreds of years for the big ones, as best as can be determined by glaciology.  Regarding the videos, I'd also want to see where those time-lapse cameras were located -- probably in the southern regions where access is possible, so it would represent only a small part of what's happening.  Southwestern coastal Greenland was defrosted and vegetated prior to the Little Ice Age, during the Medieval Warm Period, when the Norse colony was there, living off coastal fishing, growing crops and raising cattle and sheep.  That has been impossible since those colonies were abandoned due to the return of ice conditions hundreds of years ago, but I've read some of the same old habitation ruins are now emerging from under that coastal ice, which is slowly melting back. The same is happening in the Alps, as some high-altitude mountain passes formerly habitated or used as migration paths by humans during the Medieval Warm Period, but covered with ice during the Little Ice Age, are now reappearing once again with the melt-back.  It seems a  warming has been occurring since around 1850 -- the big question remains, if this will melt the big ice cap covers -- climate cycle history going back at least 10,000 years suggests this won't happen, and it appears the assertions of increased droughts and hurricanes won't materialize either.

Since Mars is also experiencing a withering of its ice-cap, it suggests we actually have "solar system warming", with some solar output variation behind such things.

James DeMeo

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