Robert, Yes, there are instances of large, abrupt changes in the paleoclimate record. However, those changes are usually found to be due to causes which do not pertain to today's Earth. You are apparently claiming that those changes are the entirely the result of internal oscillations within the atmospheric system, which is not at all apparent. The YD, which you have repeatedly offered as such an abrupt change, was due to Ice Age conditions that do not now exist. Other large changes, such as that from really massive volcanic eruptions, are not internal to the climate system, but external forcings which might push the climate over a threshold that the system was slowly approaching, but that does not suggest that we can not understand the climate system absent such events.
I think your rants continue show a failure to understand the basic stability of the Earth's climate system, as evidenced by the proxy records over the past 10,000 years. The problem with global warming is that we may be pushing the whole system toward a new normal to which humanity and the rest of the natural world may not be able to adapt to if some otherwise small push kicks the system past a threshold. We know that volcanic eruptions happen and any serious effort to understand climate must look at the paleo data with that in mind. You have refused to consider the impacts of volcanic eruptions which I have pointed to in previous posts. You also have refused to discuss the ocean circulation and the THC, which are known to exhibit variation which impacts the climate in the atmospheric portion of the entire climate system. Looking only at various indexes without seeking understanding of the mechanisms which drive them is either a fools game or a veiled effort at obfuscation. E. S. ----------------------------------------- On Apr 21, 4:28 am, Robert I Ellison <[email protected]> wrote: > 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. > -- 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
