Robert Indigo Ellison wrote: [cut] > Here’s another view of the problem – perhaps one that is a little more > nuanced, is peer reviewed and is less of an undergraduate level > blog. > > ‘Sensitive dependence and structural instability are humbling twin > properties for chaotic dynamical systems, indicating limits about > which kinds of questions are theoretically answerable. They echo other > famous limitations on scientist’s expectations, namely the > undecidability of some propsitions within axiomatic mathematical > systems (Godel’s theorem) and the uncomputability of some algorithms > due to excessive size of the calculation.’ > > http://www.pnas.org/content/104/21/8709.full.pdf+html > > Although there are climate models their veracity has not been > demonstrated – they are best described as plausible. The only > reasonable confirmation is in comparison with an untuned reality. It's > not looking real good at the moment. > > You guys are just making things up as you go. To what purpose? I > wan't to learn - I wan't real discussion and debate - not this play > school stuff. Research - show me the science - don't bother me with > glib trivialities.
Robert, That reference to the PNAS looks interesting and will take some effort to understand. However, you mention Broecker, previously pointing to Alley's long paper about the THC. If the THC exhibits variation, as seen in recent measurements, then I think you should include this process in your discussion. Tsonis and Swanson look only at the broad scale variations, not at the actual processes and thus I think their work is not predictive. The postulated change in climate after the middle 1970's may have been the result of a change in the THC, the results of which were not noticed for several years. That the formation of bottom water in the Greenland Sea appears to have stopped by the early 1980's implies that the THC which produces that bottom water also weakened or stopped at just the time period you and others have focused on. Recent freshening seen in the surface waters of the Nordic Seas may foreshadow another period in which the THC is weakened. This may already be happening, as we are in the midst of the third winter in which one indirect indicator points to the lack of sinking in the Greenland Sea. There's been considerable effort to model the THC since the first simple 2 box ocean model was presented in the 1960's. The models have improved and these efforts are described in the links provided in Alley's overview paper. If you really want to see the research, you must make the effort to read thru his references. Your attempt to focus only on the chaotic nature of the long term data appears to be an effort to gloss over the serious work to study the workings of the THC, which, were it to shutdown completely, produce major changes in climate and weather around the North Atlantic and other regions of the Earth as well. I share your stated concerns regarding the possibility of abrupt climate change. The difference is, I think we may already be seeing it happening as we write while you appear to be uninterested. You want data? Here's some data: http://en.wikipedia.org/wiki/File:Decrease_of_old_Arctic_Sea_ice_1982-2007.gif E. S. --- -- 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
