On Sat, Dec 01, 2012 at 09:03:35AM -0500, Roger Clough wrote: > Hi Russell Standish > > Be that as it may, even a study over the last millenium > would be based on inadequate data compared to the > data from the Vostok ice cores. The hockey stick data > used by Gore and others could possibly be a real change, > but it pales in comparison: > > http://www.daviesand.com/Choices/Precautionary_Planning/New_Data/ > > > so there is some undetermined cause of these cycles which occurred long > before the > automobile or industrial production. There is a theory based on earth's > inclination or wobble called > the mikhailovich cycle, but the periodicity, although close, doesn't match.
As I understand it, state of the art understanding has it that the Milankovitch cycle is the initial cause of the cyclic variation in glaciation, is not sufficient in itself to generate the temperature variation. Rather, various positive feedbacks amplify the Milankovitch cycle into the large glaciation cycle. That would also explain why the period doesn't match exactly. > > My own belief (not original) is that the CO2 is expelled and redissolved from > the vast reservoir of > the oceans as temperature varies. C)2 is much more soluble in cold water. > Yes, that would another +ve feedback. But a rather minor one, I suspect. A 2-5 degree temperature variation out of 300 degrees (room temperature on the Kelvin scale) doesn't sound like it would change CO2 solubility by much. By contrast, we've seen a near doubling of CO2 concentration since preindustrial times, which doesn't seem explainable from ocean temperature trends. > So why is the arctic ice melting but in contrast only melting slightly at the southern pole ? Well, it is melting a bit more than slightly in Antarctica, mostly in the Antarctic peninsula. Many of the glaciers in West Antarctica have accelerated, just as they have in Greenland. By contrast, East Antarctica seems stable, which is just as well for us humans. In the arctic, there is a strong +ve feedback from the fact that open ocean has lower albedo, so absorbs more sunlight during summer, heating the ocean, and preventing buildup of ice during Winter. By contrast at the South Pole, the ice sheet is some 3km thick - it will be a long time indeed before the ice has melted enough for the albedo effect to start accelerating things. > It may be related to El Nino and La Ninja, which are unevenly distributed. I > believe El Nino > (which is associagted with warming and is now present) is the cause of north > pole melting. > El Nino is associated with warming of the ocean off South America, and corresponding cooling of the Coral sea. It causes droughts in Eastern Australia, and rain in Chile. La Nina is the reverse situation. It causes a lot of rain here in Australia, and somewhat cooler weather. I thought we were still in La Nina (we had a lot of rain last year), but I see the current value of the ENSO index is neutral - neither El Nino nor La Nina. I would assume that polar warming would be more influenced by the Artic Oscillation than ENSO. I'm not sure how connected the AO is to the ENSO. But, I don't claim any expertise in these matters :) -- ---------------------------------------------------------------------------- Prof Russell Standish Phone 0425 253119 (mobile) Principal, High Performance Coders Visiting Professor of Mathematics hpco...@hpcoders.com.au University of New South Wales http://www.hpcoders.com.au ---------------------------------------------------------------------------- -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-list@googlegroups.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.
