Log in

Previous Entry | Next Entry

Sufficient Causes

Cycles Riding on Trends

A very long time ago, I saw a graph that related the frequency of the sunspot cycle with the temperature of the earth.  This was just after the Global Cooling scare and just before the Global Warming scare became institutionalized with its own bureaucracy.  What I noted was that as the sun hit maximum more frequently (shorter frequency) the earth warmed up, and when it hit maximum less often in a given time frame (longer frequency) she cooled down.  The pattern matched perfectly to the pre-1940 warming, the 1940s-1970s cooling, and the post-1970s warming. 

My own personal prediction at the time was that there was likely a 30-year rhythm in place, with the sun beating faster for 30 years, then beating slower for thirty years.  "I expect temperatures to increase until around 2000," I said, "then level off and begin to drop again."  

Since then, we have discovered the Multi-decadal Oscillation. 

Having once read the fascinating book CYCLES by Dewey and Dakin, I was familiar with the idea of cycles riding on the backs of trendlines (or even of other cycles).  Most people seem to subconsciously assume a mean value of zero for a cycle.  Anyhow, here is a dude who takes an assumed linear warming trend for the end of the Little Ice Age [perhaps related to the general increase in solar activity since the Maunder Mininum, and laid on its back a 30/30 MDO.

The red dot with the green arrow pointing to it is You Are Here 2009.

As you see it neatly accounts for the global cooling from ca. 1940 to ca. 1970 as well as for the "accelerated" warming since 1970.  (Since the cycle is going up AND the trendline is going up.) 

It also nicely accounts for the leveling off of temperatures in the past ten years and the drop in the past two.  Temperatures are of course still "high" [thank goodness], but that is because we're on a sine wave roller coater.  The red dot is set to do some sliding downward for the next 20-30 years. 

Hilaire Belloc once famously observed that we are always too impressed with the immediate past and are prone to project it unreflectively into the future.  [He was writing in the 1930s about recently impotent Islam.  He said, do NOT expect this to continue.  Look at the longer-term history.]  Is this psychology related to human lifespan?  So it is no surprise that there was some alarm in the 1970s about the recent cooling; and a much more organized and bureaucratized alarm over warming in the 1990s.  If you take any section of Immediate Past Data and simply project it, you will wind up with a New Ice Age or a Global Warming.  The alarm over the next phase of global cooling will, since the institutional mechanisms are now already in place, with be orchestrated much more seamlessly.  (Never expect a government agency to suggest there is no emergency to justify its funding.) 

What I learned in quality assurance is that most secular [= time] series in an uncontrolled process reflect the joint affects of multiple causes, and each cause contributes some portion of the overall pattern.  The kinds of things that cause a spike are different from the kinds of things that cause a shift, and these are different from the kinds of things that cause a trend, or which cause a cycle. 

In the simple pattern above, 1) the trend has a cause - and that cause is something operative over the whole time of the trend; and 2) the cycle has a cause, and that is something that is occurring on a regular and repetitive basis.  There may in addition be more than one trend line, each with a different cause and more than one cycle, as well as sudden shifts (tipping points), spikes (Mt.Pintatubo), etc.  But the chances are that whatver caused the Little Ice Age to end and whatever causes the MDO accounts for the bulk of the variation. 


( 15 comments — Leave a comment )
Apr. 19th, 2009 01:11 am (UTC)
I think I get what a spike, a trend, and a cycle are, in the sense that I could graph any of them, or pick them out on your graph. But I'm not sure what you mean by a shift. Could you give an example, and perhaps show a graph that represents a shift?
Apr. 19th, 2009 01:33 am (UTC)
A shift is an abrupt change in mean level. If the shift is all that's going on, data will fluctuate around a particular value up to the shift point, then will start fluctuating around a different value. Examples include business failure rates in the US before and after the Great Depression, solar magnetic field strength a couple of years ago [if I can find the graph again, I will post it.] Basically, it means things like: the setting on the machine has been changed, the tooling has been replaced, the tooling broke, a different operator is running the machine, a new lot of raw material is being used, a new measurement instrument in use. [Happened on a time plot of print-to-perforation measurement of pharmaceutical blister packs. Nice stable series around a nice constant average. Then one day, poof, the numbers started to vary around a different mean entirely. The reason: they were using a different ruler to make the measurement!]

Apr. 19th, 2009 01:40 am (UTC)
So a shift is like a spike, except that it doesn't revert to the previous value?
Apr. 19th, 2009 02:29 am (UTC)
That's one way of putting it. Or a spike is a temporary shift.

This is somewhat crude, but you get the picture:

If you can find the old AT&T SPC Handbook, it is very nice.

Apr. 19th, 2009 05:11 am (UTC)
Central Tendency Tendency
I had an argument with a physicist of our mutual acquaintance over global warming, regarding error bars.

Early Mann hockey stick curves included error bars.

The projection appeared horrific: boiling seas and swamped cities.

That is, if one were hypnotized by the central-tendency best-fit line instead of the deviation area.

This is the thing I cannot get people to realize: as long as one is within the bounds of the area of measurable error, one can draw any non-recursive line one wants.

Jan. 26th, 2010 08:24 pm (UTC)
It's right there in your graph, you ADMIT that it's REAL! Argument OVER. ARGUMENT OVER.

...or that's what the AGW zealots will say if you show them this graph. They'll conveniently forget the hockey stick and the Dire Warnings they made part of their liturgy; the story will be "HYPOCRITE DENIERS ADMIT WARMING EXISTS".
Jan. 26th, 2010 09:42 pm (UTC)
Alas, that was never the real issue. WHY the Earth has been warming, lo, these past four centuries is the puzzle. The CO2 effect, by itself, is insufficient. It all depends on the supposed feedback loops and which way the adjusted data is nudged. These feedback loops are not by any means as well-established as the Arrhenius Effect.
Jan. 26th, 2010 10:02 pm (UTC)
No, that's not hard. We've been warming since the Ice Sheets retreated, and the little Ice Age 400 years ago was a deviation from that overall trend.

The Ice Ages themselves are a harder problem, of course ...
Jan. 31st, 2010 04:53 pm (UTC)
You're right, the CO2 on it's own is insufficient. But when you add in water vapor effects, and water is a powerful greenhouse gas you get the right answers. The sun accounts for a fraction if the warming too.

Jan. 26th, 2010 09:57 pm (UTC)
Cycles and crises and change and tippings; it's all (politically and financially) in how you describe it.

Speaking of words, that would be "seamlessly", not "seemlessly". Although it's fun to try to imagine just what seemlessness might be ...
Jan. 26th, 2010 10:05 pm (UTC)
Re: Words
"Seemless" would be something that did not seem to be anything.
Jan. 26th, 2010 10:08 pm (UTC)
Re: Words
Nothing to do with unseemliness, then?
Jan. 26th, 2010 10:32 pm (UTC)
Re: Words
So it would seem.
Jan. 27th, 2010 02:17 am (UTC)
climate Cycles
I seem to remember reading about a 400 year cycle from soil samples in central america. Relating to the various civilizations problems. Adding those into the 30 yr cycle might explain some of the deeper temperature cycles.

Feb. 4th, 2010 03:13 am (UTC)
Wondering about "IPCC Prediction" line
What is the source for that "IPCC Prediction" curve in the upper right? Is that based on a specific publication, or a specific prediction made by the IPCC and/or some of its members?
( 15 comments — Leave a comment )


Captive Dreams

Latest Month

June 2015


Powered by LiveJournal.com
Designed by Taylor Savvy