More thoughts

milankovitch-cycles-chart-3Following a few useful comments on the previous post (now I’m a CO2 denier). I went for a walk on out local nature reserve – and unfortunately was distracted by the Lenzie Chainsaw Massacre.
However, I’m now viewing this cycle differently. The key is whether or not the cycle is “triggered” by something else. I had been working under the assumption that something might have been triggering a chain of events which is why we get the sudden rise and slow decline in temperature.
But walking along, I began thinking about the signal being the combination of two other signals: a sawtooth “|\|\ ” and a regular cycle. “∩∩∩∩”. In some way the temperature change was becoming more susceptible to the milankovitch cyle in proportion to the scale of the saw tooth.
I already knew that the ups and downs of the decline, tended to coincide with Milankovitch cycles (see 50 – 100k BP in the above). But I was still trying to adapt this to a trigger hypothesis.
And then it dawned on me that “trigger” and the “combination” hypothesis, would produce different results. When they don’t start at the same time, the trigger hypothesis says that it will either trigger or not. Whereas the combination hypothesis says we should get an irregular waveform. (the start of the sawtooth will not coincide with the rise of the ∩, so we get half a ∩ instead of a nice whole ∩)
And looking around 580k BP, we do see what could be this irregular waveform and again at 730k BP.
So, I might very well be throwing out everything I’ve written since the summer (albeit more effort has been spent in thinking than writing).
Of course – too early to say what could be causing this sawtooth wave and really difficult to understand how we could get controlled positive feedbacks modulated by this sawtooth wave. However, whilst I feel like I’ve had a “go back to go” card, it is definitely a step forward (joke).

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4 Responses to More thoughts

  1. anng says:

    Trouble is, there’s loads of influences on the climate. I don’t go along the IPCC type of statement that small changes such as over the sun-spot cycle, or changes in the solar wind and magnetism are “too small” to account for discernable changes in temp. There’s definitely some sort of correlation with sun cycles (like the present pause coinciding with a quiet sun). Maybe the sun somehow influences ocean circulations? Everything’s “Yeah, approximately, but not totally”. It;s a complex chaotic system.
    But my main thoughts are that water is the most common greenhouse gas, and it can give negative feedback by making clouds (with dissolved carbon-dioxide) as well as positive acting as a classic greenhouse gas and ice altering the albedo. I came across this paper recently which proposes another way water can give negative feedback:-
    http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50772/abstract
    Not to mention that there’s microbes in clouds which make a difference to their formation.

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