Guest post by J Storrs Hall
There are several ways to predict what the temperature trends of the next century will be like. The standard method of prediction in science is to create a theory which embodies a model, test the model experimentally, and then run it into the future for the prediction. There is another way, however, which is simpler in some ways although more complex in others. That’s simply to remember what’s happened before, and assume it will happen again.
Here’s a record of what’s happened before, which most WUWT readers will be familiar with. It’s the GISP2 Greenland ice core record, shown for the Holocene:
I have shamelessly spliced on the instrumental record in red (by setting the temps in 1850 equal); it is the HadSST record.
When I first started looking at GISP2 it seemed to me that there were several places in the record that looked very much like the sharp spike in temperature we’re experiencing now. The obvious thing thing to do seems to be to overlay them for an easy comparison:
Here I’ve plotted the 400 years following each minimum in the record that leads to a sustained sharp rise. There were 10 of them; the first five are plotted in cyan and the more recent 5 in blue. You can see that in the latter part of the Holocene the traces settle down from the wilder swings of the earlier period. Even so, every curve, even the early ones, seems to have an inflection — at least a change in slope — somewhere between 200 and 250 years after the minimum.
The hatched black line is the average of the 5 recent (blue) spikes. The red dots are the uptick at the end of GISP2 and HadSST, spliced at 1850. Note that ALL the minima dates are from GISP2.
Prediction of the 21st century is left to the reader as an exercise.
Read ’em and weep.
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Am I the only one hoping for more global warming?
Thanks! A great comparison!
Personally i believe the Grand Minimum – the coming Eddy minimum – will send us 5 deg C lower like the Wolf minimum did after the MWP within 20 years. That’s what i’m planning for. Wished i had gloves on the bike this night coming home from the pub in July in Germany at 0:30. Cooling is already imminent here IMHO. “Inflection” in your words….
(Notwithstanding fake statistics by GISS and NOAA)
We are cooling, folks; for how long even kim doesn’t know.
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You are learning, Grasshopper. Now you must apply for huge grant. Sensei gets honorable movie rights.
The standard method of prediction in science is to create a theory which embodies a model, test the model experimentally, and then run it into the future for the prediction. There is another way, however, which is simpler in some ways although more complex in others. That’s simply to remember what’s happened before, and assume it will happen again.
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Whether you remember it in your brain….or remember it in a computer
it’s still the same…….we can’t predict the future
Great post J, and something to think about…………
I think your graphs show that we will likely see a much colder climate over the coming decades. Since that means problems with growing food, and we now have over 7 billion people to feed; it don’t look good to me.
To add to the above …
A useful prediction is one that contains sufficient detail to reduce the number of explanations. Even better is a prediction that will rule out competing explanations.
Prediction is unhelpful if it leaves the field open to competing explanations as it does nothing to reduce scientific controversy.
A poor prediction is to claim that temperature will rise because it does nothing to favour one reason or to challenge other reasons.
The big red spot is an example of a much more acceptable prediction. Temperature might rise, but the big red spot is a very particular pattern of warming related to claims of the enhanced greenhouse effect. Other reasons for warming might cause a different pattern, as Chapter 9 of AR4 takes the time to explain.
Likewise, if that particular pattern of warming is not observed, the correct response is to conclude that the enhanced greenhouse effect is falsified.
J,
Interesting way to look at the data. I hope you will be able to plot the next couple of red datum- to see what the slope is up to.
Is there a way to calculate sun activity for the same periods ?
Great example of heavy use of common sense. Are you an Engineer (it takes one to know one!)?
I know predicting the future by looking in the rear view mirror is not recommeded, but for the well established cycle you’ve highlighted, it’s going to take a significant change in something to produce a different result. A minor change in a trace gas doesn’t qualify as that something in my book.
Quite clearly the end of the world is up next…
/sarc
Did somebody say “unprecedented”?
The 2nd graph is how it’s done. It shows what the weather/climate feels like: Going down real soon, hard by the bow.
In fact, the present curve looks just like a yearly cycle, January to December.
The 1850-present record, though it is a splice-on, looks spent. If Mann and others are going to present warming biased splice-ons, and keep recycling them as proof of warming, that 2nd graphic is the way to go. Relativity is honest.
Please note:
(1) HadSST is not local to Greenland so the red extension here may in fact be a larger peak.
A claimed nearby T reconstruction from Greenland itself has been presented (http://www.skepticalscience.com/10000-years-warmer.htm), a simplified version of which I made here:
http://oi53.tinypic.com/sg2wav.jpg
(2) A similarly long ice core from Antarctica (Vostok) does not correlate to this one:
http://www.skepticalscience.com/pics/Bond-events2.png
Unless you address these claims, here and on the SS web site, AGW enthusiasts will only scoff, mightily, and thus I no longer use the Greenland ice core in my usual package of arguments, since I don’t yet have a strong come back.
rbateman @ur momisugly 4:44
I like your yearly cycle. And here we are on July 1. Perhaps CAGW was just a Midsummer’s Night’s Dream.
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On the other hand if you want to consider what would happen to our civilisation if some if the more extreme temperature spikes in the record were repeated, go right ahead.
Let’s look for example at cereals like rice and wheat. As suitable temperature zones for these crops move towards the poles, what happens to the amount of land available? Since the earth is a sphere it likely goes down. Seems like Russia and Canada are going to be big winners.
I don’t believe those graphs. I mean it’s impossible to believe them because just one look at them, especially the first one should be enough to convince any sane person that current temperatures are not outside of natural variation. Why on Earth would anyone think otherwise?
Am I going mad or what?
Interesting post, thank you. “shameless splicing” – now where have I seen that before? When you look at the bigger picture the current trends all look precedented.
But…isn’t GISS Arctic temps “borrowed/filled-in/call-it-good” from a non-local source? If they can do it and call it appropriate, how come we can’t say HadSST is good enough for Greenland?
Nik,
You don’t have a strong comeback? Listen to yourself. A skeptic does not think like that. A skeptic follows the evidence – even if it is mixed.
The idea the Greenland temps are a proxy for global temps is absurd. That’s why there is no comeback! The evidence is clear the GHG’s are warming the world. Follow the science. Hint: science is done by scientists not blogggers.
Hope you are wrong!
This is not prediction. It is extrapolation. You are picking up the debased language of the Warmista. It will bite you in the behind.
Scientific prediction is a matter of having some reasonably well confirmed physical hypotheses and some set of initial conditions describing observable fact. Together the hypotheses and the initial conditions imply sentences describing observable phenomena in the future, unless you are retrodicting the past.
Looking at past graphs for patterns that resemble existing patterns is harmless enough and might give people some good ideas. However, it is not different in principle from reading chicken bones.
Finally, models are not found in theories or hypotheses. Models are analytic tools that can be used for investigating unknown assumptions in a theory. Using models to forecast the future is reading chicken bones.
Well I’ll use NASA for a proxy and state that the colder it was said to get the farther out to space NASA got. Later, when it got presumably warmer the less interested NASA to got to get out into space.
It’s really the coincidence that when NASA took on Hansen and let him bloom and come out and behave how ever, the higher the temperature got, the less NASA could sustain being a space faring organization, the more tax payers’s hard earned cash was needed to sustain a non space faring space organization model their way into even more of the tax payer’s hard earned cash. Go figure. :p
Splicing a global average temperature onto a point site is an interesting trick. Do you think the global-average variability is a valid comparison with this point variability?
What is the long term average temp on that top chart?