Five poor summers in a row

[kenneal - lagger]

While I believe that CO2 warms the world and that much of it is produced by us humans and we should do something about it, the ultimate source of our warmth is the sun. That is likely to be going into a 30 year period of low activity which has, in the past, produced minima in world temperatures on a 166 year cycle. This low temperature event should be on the scale of the Maunder Minimum and there is likely to be another event on the same scale around 2100, although I might not be around to witness that.

I am, therefore, working on the basis that we are going to have lower temperatures and hard winters for the next few years. How hard those winters are will be interesting to see as it will give us a good idea of the relative strength of the sun's variability and CO2 in their effect on the world's climate.

Just as I believe in precautionary preparations for Peak Oil and economic collapse, I believe in precautionary preparations for Climate Change warming but in a temporarily cooling environment.

[clv101]

...the ultimate source of our warmth is the sun. That is likely to be going into a 30 year period of low activity which has, in the past, produced minima in world temperatures on a 166 year cycle.

My judgment of the literature is that we can't say 'likely'. It certainly could, but I don't see the evidence for likely.

[biffvernon]

A useful rule of thumb is to regard any mention of 'cycles' as ballony, unless it refers to pedal powered transport.

[kenneal - lagger]

So the sun spot cycle is ballony then, is it? Most women would not argue that the menstrual cycle is ballony. I'm sure I could think of a few more ballony cycles if I could be bothered and it wasn't the wrong time in the lunar cycle.

[clv101]

A useful rule of thumb is to regard any mention of 'cycles' as ballony, unless it refers to pedal powered transport.

I don't buy that. The climate system is dominated by many different cycles; daily, seasonal, annual, decadal, and significantly longer to include Milankovitch and even coalescence and brake up of super continents. We are continually living in a superposition of innumerable cycles with widely varying time periods. The trick is to understand these cycles so as to be able to identify signals beyond these secular modes of variation.

[kenneal - lagger]

You can add the Dalton Minimum in from 1790 to 1830 which wasn't quite so cold. Looks pretty cyclical to me.

See it all at http://en.wikipedia.org/wiki/Maunder_Minimum

[kenneal - lagger]

Oh! I nearly forgot. There's the approximately 365.25 day cycle we call a year! That's a long bike ride, that one and it includes four seasons as well.

[biffvernon]

I don't buy that.

Well of course I don't really buy it either, but the point is that cycles do get more credence than they deserve. Humans are good at recognising patterns and we search for patterns in case there are some and we see patterns even when there aren't any. This is particularly apparent in complex dynamic systems when sometimes a phenomenon repeats itself a few times - "Oh look, a pattern, a cycle!"- when all that has happened is that the phenomenon has repeated itself a few times. There is no guarantee that it will repeat again.

Maybe not always balony, but be very wary of anyone who calls cycles.

[biffvernon]

Let's just take a look at that squiggly line again. Imagine nobody had ever told you about cycles. How would it be described if you had never heard of cycles? Hmmm...the line seems to go up and down and up and down with some of the ups and downs bigger than others. Just what one might expect from a chaotic dynamic system operating within the limits imposed by attractors.

[kenneal - lagger]

I would say that it is a series of fairly regular repeating ups and downs and I've put the science behind it up on here before.

7 x 166 + 875 = 2019 and the next dip has been predicted for about 2030 so not a bad cyclic prediction when you take into account the difficulty of reading the start date from the graph.

[biffvernon]

We'll have to wait till 2030 before we know whether it is not a bad cyclic prediction.

And even then we won't actually know if it was a cyclic prediction or a lucky hit.

[An Inspector Calls]

Let's just take a look at that squiggly line again. Imagine nobody had ever told you about cycles. How would it be described if you had never heard of cycles? Hmmm...the line seems to go up and down and up and down with some of the ups and downs bigger than others. Just what one might expect from a chaotic dynamic system operating within the limits imposed by attractors.

Never heard of Fourier then?

[cubes]

You can add the Dalton Minimum in from 1790 to 1830 which wasn't quite so cold. Looks pretty cyclical to me.

See it all at http://en.wikipedia.org/wiki/Maunder_Minimum

Why is that graph backwards?

[An Inspector Calls]

Let's just take a look at that squiggly line again. Imagine nobody had ever told you about cycles. How would it be described if you had never heard of cycles? Hmmm...the line seems to go up and down and up and down with some of the ups and downs bigger than others. Just what one might expect from a chaotic dynamic system operating within the limits imposed by attractors.

Never heard of Fourier then?

To be more explicit: the Fourier Transform (not his work on the greenhouse effect).

http://en.wikipedia.org/wiki/Fourier_transform

[JavaScriptDonkey]

Never heard of Fourier then?

To be more explicit: the Fourier Transform (not his work on the greenhouse effect).

http://en.wikipedia.org/wiki/Fourier_transform[/quote]

I think they actually use Wavelets due to doubt about the periodicity of the events. Doesn't Fourier pre-suppose that there is valid frequency information to find?

Frick's (et al) Wavelet Analysis of Chromospheric Activity Variations (US AstroPhysical Journal, July 1997 <online>)