On Mon, 2010-02-01 at 02:48 -0800, Robert Indigo Ellison wrote: > But a metaphor for what? I know that global warming is involved > somewhere but I can’t quite make the connection.
... > There is a need to think in terms of total systems - difficult as > there are so many gaps in understanding and lack of data - rather than > trying to isolate a specific factor in a causative chain. It is > useful to think in terms of climate shifts rather than global warming > necessarily. I think it is helpful to have some understanding of > complex systems theory - as a metatheory, an organising principle, for > ideas about abrupt climate change. The connection is that both airflow over a wing is chaotic and climate is chaotic, yet meaningful causal statements can be made about both. As far as I understand it: Climate is usually weakly chaotic. It is, after all, just the average of weather. So there is clearly a limit to the short term accuracy of predictions. However, there is a lot of evidence that climate is not usually strongly chaotic, and thus longer term predictions are more reliable. Airflow over wings is usually weakly chaotic. Even in ideal conditions, 99% of the surface of the wing of the Wright Flyer had chaotic flow, aka turbulent flow. And in cases flying in turbulent air, often the case near the ground, 100% of the air flow on any wing can be turbulent. Yet that doesn't mean that complex system theory is needed to design an aircraft, or to fly one. > 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. As for today's weather, exactly how closely could a climate model predict this year's weather? Where is the boundary between climate and weather? As for untuned reality, the cross check between models and the Last Glacial Maximum seems to me to be a fair confirmation. -- Phil Hays <[email protected]> -- 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
