The climate models use the same Navier-Stokes equations of fluid motion that Edward Lorenz used in his convection model. McWilliams describes both 'sensitive dependence' and 'structural instability' in the 2007 NAS paper linked to.
http://www.nap.edu/openbook.php?record_id=10136&page=R5 'Large, abrupt climate changes have repeatedly affected much or all of the earth, locally reaching as much as 10°C change in 10 years. Available evidence suggests that abrupt climate changes are not only possible but likely in the future, potentially with large impacts on ecosystems and societies. 'This report is an attempt to describe what is known about abrupt climate changes and their impacts, based on paleoclimate proxies, historical observations, and modeling. The report does not focus on large, abrupt causes—nuclear wars or giant meteorite impacts—but rather on the surprising new findings that abrupt climate change can occur when gradual causes push the earth system across a threshold. Just as the slowly increasing pressure of a finger eventually flips a switch and turns on a light, the slow effects of drifting continents or wobbling orbits or changing atmospheric composition may “switch” the climate to a new state. And, just as a moving hand is more likely than a stationary one to encounter and flip a switch, faster earth- system changes—whether natural or human-caused—are likely to increase the probability of encountering a threshold that triggers a still faster climate shift. We do not yet understand abrupt climate changes well enough to predict them.' Abrupt climate change, tipping points or chaotic bifurcation? Basically - I think you making it up as you go along. On Apr 20, 11:17 pm, Tom Adams <[email protected]> wrote: > On Apr 16, 8:01 pm, Robert I Ellison <[email protected]> > wrote: > > > But are tipping points predictable? > > Some are and some are not. Something that varies can have both > predictable and unpredictable tipping points and everything in > between. > > Tipping points can be unpredictable due to chaotic processes or due to > mere randomness. > > I am arguing that you need to use scientific definitions, not > metaphors or the everyday meanings of terms. There are 2 different > things: > > 1. Chaotic processes > 2. Tipping points > > You are probably understating the importance of tipping points by > confusing them with chaotic processes. > > > Chaos theory is a simply a > > metatheory of change in complex systems and a climate 'tipping point' > > is merely an example of chaotic bifurcation in a complex and dynamical > > system. > > Not true. > > > Small initial changes lead to a change in one component which > > drives change in another etc. A 'cascade of powerful mechanisms' > > leading to a nonlinear climate response. Abrupt climate change, > > tipping points, chaotic bifurcation and sensitive dependence all have > > the same meaning. > > Not true. > > > > > I think climate is chaotic at all time scales - in the multidecadal > > timescale as > > inhttps://pantherfile.uwm.edu/kravtsov/www/downloads/GRL-Tsonis.pdf > > There do seem to be multidecadal chaotic processes. > > We don't have much evidence on longer time scales. > > *All* time scales? Kinda a broad claim. > > Of course you are right that the idea of climate being the average of > the weather must be bunk or an approximation of limited applicability > at best. The climate parameters do keep changing on all time scales > till there is no climate. > > > > > Major climate shifts around 1910, the mid 1940's, the late 1970's and, > > in a later paper(Has climate recently shifted? Swanson and Tsonis > > 2009), 1998/2001. And please note that changes are evident in real > > world data and are extensively documented in scientific literature. > > Climate is not chaotic only in the short term - as in weather - but at > > every scale from ENSO to decades, ice ages and beyond. > > > Climate models are themselves chaotic > > -http://www.pnas.org/content/104/21/8709.full.pdf > > - suffering not only from 'sensitive dependence' but from 'structural > > instability'. The latter involves chaotic bifurcation as a result of > > small changes (well within the limits of quantification) of boundary > > conditions. > > Can you give an example? > > I think you are confusing chaotic processes with processes that are > difficult to predict because we have low accuracy of the initial > conditions, but I am not sure. > > > There is thus no unique solution to the climate problem > > within the constraints of present day understanding. > > Isn't that true for plenty of non-chaotic processes? > > > Modellers pick > > their best run subjectively and send it to the IPCC where it is > > graphed along with a number of other subjectively selected > > 'solutions'. Very average indeed. > > > So we are 'predicting' a chaotic system by means of another, and > > different, chaotic system? Give me a break. 'The science' has got it > > wrong at the level of underlying assumptions - mindless repetition of > > the error leads us nowhere. > > -- > 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 > athttp://groups.google.com/group/globalchange -- 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
