Dave, I agree. Maybe the "tug of gravity" can be endothermic or exothermic depending upon local conditions
On Mon, Aug 25, 2014 at 1:08 PM, David Roberson <dlrober...@aol.com> wrote: > You have the right general idea about the fit not being adequate. I > suspect that their model is far more complex than a simple linear model and > of much higher order. The net prediction of future temperatures is a > result of how all of these terms combine and it will diverge more and more > rapidly from the fitting base data as time progresses. The higher order > effects contain the more rapidly changing processes. > > Cyclic behavior can be modeled by a series. A good example of this is > demonstrated by the infinite series that can be used to construct a sine > wave. For small time periods the linear term does a pretty good job of > matching the curve. As you move forward in time, the other, higher order > terms, become the most significant ones which then allows the overall > function to go through its cyclic behavior. > > The appearance of the temperature pause and the description that it might > well last until 2025 and is cyclic strongly suggests that the underlying > phenomena responsible for this behavior has been in effect during the rapid > temperature rise and could be one of the reasons for the high slope seen. > If so, the very dominate earlier seen hockey stick temperature rise has > overstated the true underlying increase rate. > > As corrections are included to the models we may find that mans > contributions are overwhelmed by natural effects and that is why I feel > that caution is in order. Had there been no long term unexpected pause we > may have continued to give unwarranted confidence to the models and their > expert constructors. Some day I believe that we will be capable of making > predictions about climate change that match the real world, but that day > has not arrived. Of course even then the world throws curve balls our way > in the form of volcanoes, changing solar activity, and etc. which makes > extremely long term predictions a guess at best. > > Dave > > > > -----Original Message----- > From: Eric Walker <eric.wal...@gmail.com> > To: vortex-l <vortex-l@eskimo.com> > Sent: Mon, Aug 25, 2014 2:54 am > Subject: Re: [Vo]:global warming? > > On Sun, Aug 24, 2014 at 6:38 PM, David Roberson <dlrober...@aol.com> > wrote: > > You also probably realize that a polynomial fit to a high power order >> yields coefficients that vary depending upon the order of the polynomial >> chosen. Many combinations of coefficients will fit the input/output data >> over a restricted range. The problem shows up once you use those >> different coefficients to project the curve forwards into unknown future >> points. >> >> We are now clearly in witness to an example of the type of problem that I >> am speaking of. ... >> > > I think the bad fit to the data you identify could just as likely be an > underfit than an overfit; i.e., they have adequately modeled the > first-order phenomenon (an increase in temperature) but failed to take into > account one or more second-order cyclical trends. > > Eric > >
