...a name media would love for global warming alarmists not to know is Roald Amundsen, a Norwegian explorer who successfully navigated the Northwest Passage on August 26, 1905 (h/t Walt Bennett, Jr.):

The North West Passage was done. My boyhood dream - at that moment it was accomplished. A strange feeling welled up in my throat; I was somewhat over-strained and worn - it was weakness in me - but I felt tears in my eyes. 'Vessel in sight' ... Vessel in sight.

Yes, ladies and gentlemen, this Passage was clear enough of ice for a wooden sailboat, with a crew of seven, to successfully navigate it more than 100 years ago. How many times in the history of the planet do you think a similar - or even more ice-free - condition existed in this area?

The polar sea ice is the biggest heat sink we've got in the ocean. Considering the specific heat of melting ice is much more than the specific heat to melt water, the big question is how fast the oceans will warm once it's completely melted.

On the other hand, ocean temperatures would only be one of many factors in the melting of the Greenland ice sheet. As far as I could find out (from the wikipedia "Greenland Ice Sheet" entry and links therein), warming air is the main contribution to glacial acceleration. Thus:

"The higher velocity of the ice is thought to be related to higher temperatures causing increased melt-water which can penetrate to the base of the glacier and hence reduce the ground friction...Unfortunately, the physics of basal lubrication ...are very poorly understood and not fully accounted for in current ice sheet models. Until those models include these effects, there is a danger that we may be under-appreciating the dynamic nature of the ice sheets.

Maybe someone else better informed could enlighten us, but I don't think there is any direct knowledge that the disappearing Arctic sea ice will have a first-order effect on the Greenland ice sheet.

Jim Hansen wrote a recent article on Scientific Reticence stacks.iop.org/ERL/2/024002 in which he describes how scientists don't do a good job of reflecting the cumulative information because it requires individuals to step outside their personal field of expertise. Five years ago a report noted that Greenland's melt rate indicated a complete loss of ice cover in a thousand years.  If you look at the globe, Greenland is unique at its latitude for having an ice cap, and is regarded as a self-perpetuating relic of the last ice age.  About three years ago the melt rate was shown to have doubled as indicated by increased runoff from inland waterways, and extreme surface melting.  Earlier this year, the rate was again doubled, due to measurements of melting of ice around the shores and the rate of exposed rock warming and melting surrounding ice.  These reports are not being reconciled with eachother, but the suggestion is that in five years we have gone from a thousand years to 250 years for a 20 foot sea level rise.

Nor do we reconcile the fact that if Greenland melts, the WAIS probably won't be unaffected.  I don't like to sound like an extremist, but I don't like to see good information neglected either.  We are seeing Arctic ice melt because over 20 times as much thermal warming has entered the surface waters of the ocean as has entered the atmosphere.  This was not adequately considered in climate modelling until a couple of years ago, and is probably only now being examined in any detail.  The Arctic melt won't raise sea level much, but it will accelerate warming due to albedo change.  It will affect thermal expansion of the ocean.   Someone will tell us how much, soon, and that estimate will be dated, soon, because there will be supplementary factors the first estimate will forget to consider.

Climate change is like that.  Yeah, it is.

- Ned