There is some question as to what would happen to the Atlantic overturning circulation by analogy to the Younger Dryas reversal in glacial retreat. Cold fresh water may stay afloat on warmer but more saline water, shutting down the convective plume in the north Atlantic.
There are some relevant paleoclimate modeling studies. You could start here: http://www.nature.com/nature/journal/v435/n7042/full/nature03617.html The overturning circulation is not well-represented in models for numerical reasons. This is one of those problems that arguably justifies a huge increase in the computational power of models (to support a large scale non-hydrostatic ocean). The course of Greenland disintegration is not well characterized, and the response is sensitive to the time and space distribution of meltwater. Recent observations (look around RealClimate for this) indicate a lot of interannual variability in Atlantic overturning. In short, it's not one of those things anyone feels comfortable predicting or even risk assessing, but there is a mechanism that might support a cooling of the North Atlantic and northern Europe, though not the "ice age" that you still occasionally see in the press. There would be consequences elsewhere on many time scales. For instance, the reduced downwelling would have to be accompanied by decreased upwelling elsewhere, probably leading to a warmer (and less biologically fertile ocean) in those places, with further consequences... I don't know that anyone has coaxed a GCM into this hypothetical, GHG rich, low North Atlantic overturning, circulation state. mt On Wed, May 21, 2008 at 12:06 PM, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > If Greenland were to melt rapidly (2 m per century of sea level rise), > what would be the impact of all the cold melt water? > > Have there been attempts to model world climate on the assumption of > rapid ice discharge into the North Atlantic? > > I've tried to get a first back of the envelope impression by > calculating the heat required to melt all of Greenland, and come to 1 > W/m2 over 50 years, but that's not really that helpful. > > (7 m of sea level rise should be about 5 m of water spread over the > whole world, that's 5000 kg/m2, heat of fusion of water is 330 kJ/kg, > and at 1 W/m2 that directly gives 1.67 e9 seconds ...) > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/globalchange -~----------~----~----~----~------~----~------~--~---
