Chaos, Attractors, CO2, Milankovic Cycles, and Ice Ages
Posted by greg2213 on January 10, 2012
WuWT has a great article on Chaos and Strange Attractors which is very readable. It explains very nicely why Catastrophic Warming isn’t going to happen and why an Ice Age very likely will.
This strongly suggests that while the the linear response assumption made in a) may be valid (per attractor) — or may not, but it will be a huge problem to prove it — the effect isless than the natural excursion, not greater than the natural excursion, and the negative feedback factors that make the multistable attractors (locally) attractive also act asnegative feedback on the CO_2 induced shift!
The latter is the fluctuation-dissipation theorem, as I already noted in one thread or another (two tired of writing to go see if it was this one). In an open system in a locally stable phase, the oscillations (fluctuations) couple to the dissipation so that more fluctuation makes more dissipation — negative feedback. If this is not true, the locally stable phase is not stable.
This is a strong argument against catastrophe! The point is that given that CO_2 is making only small, slow, local shifts of the attractors compared to the large shifts of the system between the attractors, if there was a point where the system was likely to fall over to a much warmer stable point — the “catastrophe” threatened by the warmists — italmost certainly would have already done it, as the phase oscillations over the last ten thousand years have on numerous occasions made it as warm as it is right now.
The fact that this has not happened is actually enormously strong evidence against both positive feedback and catastrophe. Yes, anthropogenic CO_2 may have shifted all the attractor temperatures a bit higher, it may have made small rearrangements of the attractors, but there is no evidence that suggests that it is probablygoing to suddenly create at new attractor far outside of the normal range of variation already visible in the climate record. Is it impossible? Of course not. But it is not probable.
Luboš Motl, of The Reference Frame, writes about Milankovitc Cycles and how some recent work has greatly tightened up their agreement with observed data. He also adds some remarks on CO2 and temperatures.
This paper by a former student of Richard Lindzen finally managed to fix Milutin Milankovič’s theory which hadn’t worked and the outcome was a theory that does work. The graph below contains both theoretical predictions as well as the observed data about the Northern Hemisphere temperature and you may see that the match is beautiful:
As the TRF article mentioned above shows, previous attempts to make the theory work displayed the right frequencies but the graphs never really agreed. The probability that the agreement above is coincidental is pretty much zero. Lots of high-frequency wiggles agree. In the future, one may optimize the Milankovič theory but these will be incremental improvements; the qualitative fact that the astronomical cycles dictate “most” of the dynamics in the glaciation cycles has been established by the graphs above.
Dynamics of CO2 concentration after fossil fuels
However, what’s even more absurd is the role that is being attributed to CO2. CO2 will only be modified due to the human activity for a few centuries which is much shorter than the time needed for the ice age cycles to collect several Celsius degrees – that requires thousands or tens of thousands of years….
Here’s the rest: Will CO2 save us from next ice age?
I do have a quibble, though. As I understand it, most plants (even grasses) have severe difficulty when CO2 levels drop below 200ppm. If it were to drop to 180ppm as LM suggests, then I suggest that we might see some major plant extinctions, beyond that caused directly by the lower temps of an ice age.
So either plants can survive at lower CO2 and the CO2 biology is not understood or, much more likely, CO2 levels were actually higher during the ice ages than we think.
Here’s a good book on understanding how Chaos works. It’s just the thing for those of us without advanced Math/Physics degrees:
On Amazon.com: Chaos: Making a New Science