Comments on: The climate votes last: Ice sheets could lose mass more rapidly http://www.cejournal.net/?p=4349 News & Perspective from the Center for Environmental Journalism Sun, 08 Jan 2012 20:05:12 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Mauri Pelto http://www.cejournal.net/?p=4349&cpage=1#comment-8209 Mauri Pelto Fri, 05 Nov 2010 14:13:40 +0000 http://www.cejournal.net/?p=4349#comment-8209 <a href="http://www.cesm.ucar.edu/events/ws.2010/Posters/phillips.pdf" rel="nofollow">Phillips presentation</a> Phillips presentation

]]> By: Mauri Pelto http://www.cejournal.net/?p=4349&cpage=1#comment-8208 Mauri Pelto Fri, 05 Nov 2010 14:09:30 +0000 http://www.cejournal.net/?p=4349#comment-8208 The GRL paper is behind a paywall, but a presentation of this project that is more photogenic anyway Phillips et al, 2010 </a> is available. The press release does not examine the true impact of this potential warming of the bulk of the ice. In a paper <a href="http://cat.inist.fr/?aModele=afficheN&cpsidt=14549260" rel="nofollow">Luthi et al., (2002)</a> examined the temperature profile of the Jakobshavn Glacier using borehole measurements. They observed the temperature to be -5 to -10 C at near surface depths, increasing to -20 C by a depth of 400 m, the cold temperatures plateaued until 80 % of the distance to the ice sheet base where the temperature then warmed to near 0 C. The velocities observed in this project indicated almost all of the motion from basal sliding and internal deformation occurred in the lowest 10-15 % of the ice stream. This is where the ice is warm. This is not unusual that basal ice is warmer and that most of the ice motion is generated here. Even on temperate glaciers most of the ice motion is generated near the glacier base due to the pressure and via basal sliding. The point is that the bulk of the ice thickness would have to be warmed considerably before it would have a signature on ice velocity and even then it is not the location where glacier and ice sheet velocity tends to be primarily derived from. The GRL paper is behind a paywall, but a presentation of this project that is more photogenic anyway Phillips et al, 2010 is available.
The press release does not examine the true impact of this potential warming of the bulk of the ice. In a paper Luthi et al., (2002) examined the temperature profile of the Jakobshavn Glacier using borehole measurements. They observed the temperature to be -5 to -10 C at near surface depths, increasing to -20 C by a depth of 400 m, the cold temperatures plateaued until 80 % of the distance to the ice sheet base where the temperature then warmed to near 0 C. The velocities observed in this project indicated almost all of the motion from basal sliding and internal deformation occurred in the lowest 10-15 % of the ice stream. This is where the ice is warm. This is not unusual that basal ice is warmer and that most of the ice motion is generated here. Even on temperate glaciers most of the ice motion is generated near the glacier base due to the pressure and via basal sliding. The point is that the bulk of the ice thickness would have to be warmed considerably before it would have a signature on ice velocity and even then it is not the location where glacier and ice sheet velocity tends to be primarily derived from.

]]> By: Steve Bloom http://www.cejournal.net/?p=4349&cpage=1#comment-8179 Steve Bloom Thu, 04 Nov 2010 00:20:31 +0000 http://www.cejournal.net/?p=4349#comment-8179 So now, with this advance, is there any other major barrier to the development of a true dynamical ice sheet model? Also, based on multiple paleo results, that thousands of years seems hard to support. So now, with this advance, is there any other major barrier to the development of a true dynamical ice sheet model?

Also, based on multiple paleo results, that thousands of years seems hard to support.

]]> By: spyder http://www.cejournal.net/?p=4349&cpage=1#comment-8177 spyder Wed, 03 Nov 2010 19:47:15 +0000 http://www.cejournal.net/?p=4349#comment-8177 While it may take thousands of years for the ice sheet to melt, what seems to matter more is how much will melt how quickly, and thus raise the sea level 1-3 meters? While it may take thousands of years for the ice sheet to melt, what seems to matter more is how much will melt how quickly, and thus raise the sea level 1-3 meters?

]]>