Story submitted by WUWT reader Nancy Green
There is a message in Marcott that I think many have missed. Marcott tells us almost nothing about how the past compares with today, because of the resolution problem. Marcott recognizes this in their FAQ. The probability function is specific to the resolution. Thus, you cannot infer the probability function for a high resolution series from a low resolution series, because you cannot infer a high resolution signal from a low resolution signal. The result is nonsense.
However, what Marcott does tell us is still very important and I hope the authors of Marcott et al will take the time to consider. The easiest way to explain is by analogy:
50 years ago astronomers searched extensively for planets around stars using lower resolution equipment. They found none and concluded that they were unlikely to find any at the existing resolution. However, some scientists and the press generalized this further to say there were unlikely to be planets around stars, because none had been found.
This is the argument that since we haven’t found 20th century equivalent spikes in low resolution paleo proxies, they are unlike to exist. However, this is a circular argument and it is why Marcott et al has gotten into trouble. It didn’t hold for planets and now we have evidence that it doesn’t hold for climate.
What astronomy found instead was that as we increased the resolution we found planets. Not just a few, but almost everywhere we looked. This is completely contrary to what the low resolution data told us and this example shows the problems with today’s thinking. You cannot use a low resolution series to infer anything reliable about a high resolution series.
However, the reverse is not true. What Marcott is showing is that in the high resolution proxies there is a temperature spike. This is equivalent to looking at the first star with high resolution equipment and finding planets. To find a planet on the first star tells us you are likely to find planets around many stars.
Thus, what Marcott is telling us is that we should expect to find a 20th century type spike in many high resolution paleo series. Rather than being an anomaly, the 20th century spike should appear in many places as we improve the resolution of the paleo temperature series. This is the message of Marcott and it is an important message that the researchers need to consider.
Marcott et al: You have just looked at your first star with high resolution equipment and found a planet. Are you then to conclude that since none of the other stars show planets at low resolution, that there are no planets around them? That is nonsense. The only conclusion you can reasonably make is that as you increase the resolution of other paleo proxies, you are more likely to find spikes in them as well.
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As a primer for this, our own “Charles the Moderator” submitted this low resolution Marcott proxy plot with the Jo Nova’s plot of the Vostok ice core proxy overlaid to match the time scale. Yes the vertical scales don’t match (numerically on the scales due to the ticks being different and the offset difference), but this image is solely for entertainment purposes in the context of this article, and does make the point visually.
Spikes anyone? – Anthony
![marcottvostok2[1]](http://wattsupwiththat.files.wordpress.com/2013/04/marcottvostok21.jpg?quality=83)
(Added) Study: Recent heat spike unlike anything in 11,000 years “Rapid” head spike unlike anything in 11,000 years. Research released Thursday in the journal Science uses fossils of tiny marine organisms to reconstruct global temperatures …. It shows how the globe for several thousands of years was cooling until an unprecedented reversal in the 20th century. — Seth Borenstein, The Associated Press, March 7th
Note: If somebody can point me to a comma delimited file of both the Marcott and Vostok datasets, I’d be happy to add a plot on a unified axis, or if you want to do one, leave a link to the finished image in comments using a service like Tinypic, Imageshack or Flickr. – Anthony
Help mods, it looks like I missed hitting [shift] on closing the start italic notation and got a period rather than a greater than symbol. I think I closed italics following “the two curves are identical…” but it does not show, please correct. Thank you.
richardscourtney,
I really tried to get through your whole post but was unable to. I had to stop reading after you wrote, “Each year mean global temperature rises by 3.8 deg.C deg.C from June to January and falls by 3.8 deg.C deg.C from January to June.
So, the warming which you want to exaggerate is about a fifth of the rise experienced during 6 months of each year.”
Please, could you reference where you got this from. I am at a lost as to how you came up with that number but feel it explains so much about your posts.
Slightly O/T:
In a Real Climate comment (#124), Shakun responds to criticism of the core re-dating issue:
http://www.realclimate.org/index.php/archives/2013/03/response-by-marcott-et-al/comment-page-3/#comment-327407
The concluding statement of this comment is interesting in that it refers to the rate of change conclusion as ‘our main conclusion.’ That is, the main conclusion of the Marcott et al paper is, as per the press release etc, the unprecedented rate of change. However, this comes not by way of the Marcott et al proxy uptick but by comparison of its slow Holocene cooling with instrumental hockey stick blade in the Mann08 composite:
Thus, while sceptics have something to work with in this defense, in the end it their sound and fury will amount to naught. All the attention that Nancy Green, Steve McIntyre etc have given to the proxy uptick is eschewed and deflected back to a defense of Mann’s old hockey stick.
Nancy, at first I thought Tamino’s shenanigans were indeed “tricks,” as you note. However, more and more I wonder if he knows how to use the tools, but lacks the fundamental understanding necessary to appreciate why and how the tools do what they do. In other words, incompetent, not a liar.
Mark
But some of these ought to show up if they were super-sized, like this one:
Nevertheless the immense warming spike of the Younger Dryas occurred. If such spikes can occur for an unknown reason, why couldn’t that unknown reason explain Modern Warming as well?
richardscourtney says, “I fail to understand any possibility of that meaning other than you were claiming that correlation of those two parameters showed the system has changed (i.e. “Null Hypothesis fails”) and I don’t understand how that can be anything other than an assertion of causality.”
No correlation or causality necessary. If atmospheric CO2 levels have changed and or temperature has changed then your null hypothesis that the system has not changed is shown to be false. Are you saying CO2 levels and or temperature has not changed or are you in agreement that the system has changed?
The consensus view is that CO2 has caused warming since 1950 (63 years), not “for well over a century.”
Nancy Green says:
April 4, 2013 at 7:44 pm
I would like to thank the many contributors that have made this the Top Post at WUWT. Wahoo! Please pat yourselves on the back. I would especially like to thank Anthony and “Charles the Moderator” for helping make this article such a success.
As the author, I would tend to think it is you who is responsible for this article being a success. The rest of us just add minor details and have a discussion on what it means in relation to the Marcott mess. You did the hard and heavy lifting and suffer the nice attacks by trolls, the rest of us just troll bait and/or troll bash.
In any regard, looking forward to future articles and I want to remind everyone once again that correlation does not imply causation. (I am looking at you Thomas.)
In my post above, that should be sinc function not sync function.
Mark T says:
April 4, 2013 at 9:16 pm
Nancy, at first I thought Tamino’s shenanigans were indeed “tricks,” as you note.
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The point of misdirection is to confound the audience so they cannot see what is really happening. Almost always this requires the performer to control the stage, to limit the audience to a specific point of view. Otherwise the illusion will break down. For this reason sites like Tamino and RC need to heavily censor and control the presentation.
The purpose of a good analogy is to change your point of view. To allow you to look at the stage from a different angle in spite of the performer, so that you can see clearly how the trick is done. In this case Tamino wants you to believe he has traveled back in time and created 3 climate spikes. He wants you to believe that these three spikes are now part of the actual proxies and are at the same resolution as the proxies.
However, that is not what he has done at all. He has drawn three spikes onto the low resolution proxies, but he drew the spikes in high resolution. Much higher resolution that what exists in the proxies themselves. He has changed the resolution without telling you the audience, hoping you will not notice. And as predicted in my article, these proxies are detectable by Marcott.
The only conclusion you can reasonably make is that as you increase the resolution of other paleo proxies, you are more likely to find spikes in them as well.
If anything, Tamino has simply demonstrated my point. He has shown that as you increase the resolution you are more likely to find spikes.
benfrommo says:
April 4, 2013 at 9:56 pm
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Thank you for your kind comments. I very much enjoyed your posting on observer bias.
One of the many positive aspects of WUWT is that different points of view are allowed. Reasoned debate may never convince the unreasoned, but it can be of great benefit to the many observers.
Mark T says:
April 4, 2013 at 9:16 pm
Nancy, at first I thought Tamino’s shenanigans were indeed “tricks,” as you note. However, more and more I wonder if he knows how to use the tools, but lacks the fundamental understanding necessary to appreciate why and how the tools do what they do. In other words, incompetent, not a liar.
Mark
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http://suyts.wordpress.com/2013/04/03/because-there-are-limits-on-learning-especially-with-the-stupid/
If you don’t want to read through the verbosity, there’s a pic that says it all.
richardscourtney, thank you very much indeed for such a detailed and clear exposition of the Null Hypothesis, specifically as it relates to the assumption of AGW. I very much admire your patience in attempting to clarify the basics of scientific principle, in the face of so much willful ignorance.
I’m sorry that neither Thomas nor ‘sceptical’ is able to follow the argument, but I (and no doubt others) will find it useful here in the UK for forwarding to friends who get their news from the BBC, and who read the Guardian, the Independent and other such AGW-addicted media outlets, due their blinkered Greenie political views.
@ur momisugly scpetical, who wrote
“No correlation or causality necessary. If atmospheric CO2 levels have changed and or temperature has changed then your null hypothesis that the system has not changed is shown to be false. Are you saying CO2 levels and or temperature has not changed or are you in agreement that the system has changed?”
richardscourtney clearly demonstrated – with citations – that records show nothing unusual or unprecedented in the warming of the last half of the C20th. So no: the variations do NOT prove any change in the system, and your argument therefore falls.
This was again explained above, for your benefit, by Theo Goodwin (April 4, 2013 at 3:34 pm)
Furthermore, all records show that the increases in CO2 lag those in temperature by several hundred years. To quote richardscourtney again, because these points are crucial to the argument against AGW:
” (b) … that feedback was so small that it failed to stop temperature rising and falling because (according to the Vostock ice core) the delay of CO2 reversal was typically 800 years after each temperature reversal.
Also, that is the longest time scale and I said “at all time scales”.
At the shortest time scale CO2 follows temperature by 5 months. This was first discovered in 1990 by Kuo, Lindberg & Thomson (ref. Cynthia Kuo, Craig Lindberg & David J. Thomson “Coherence established between atmospheric carbon dioxide and global temperature” Nature 343, 709 – 714 (22 February 1990) )
This has been independently confirmed by several others since and the subsequent studies have revealed that the time of the delay of CO2 after temperature varies with latitude.
Atmospheric CO2 was much higher than now throughout most of the time since the Earth has had an oxygen rich atmosphere. ”
/// end quote ///
Sam the First:
At April 4, 2013 at 11:40 pm you say you are in the UK.
I wonder if your are in the West Country?
The excellent and impressively knowledgeable ‘tonyb’ lives in Devon and I am in Cornwall. If there were sufficient of ‘climate realists’ in the West Country then it may be possible for us to meet-up at a pub to swap AGW anecdotes.
At very least we could amuse each other with tales of abuse we have had from warmunists, and nobody can know what may develop from such a social gathering.
Richard
There’s lots of good discussion about scientific method here. Could I just add something?
For almost all physical sciences, experiments are performed in order to understand more about reality. An experiment is a closed system, so that a scientist can change one input variable and determine whether the outputs are changed. The null hypothesis is that there will be no change, and that is deemed disproven if there is a change in output which is statistically significant (generally at the 5% level, though this is just a convenience and does in fact permit 1 in 20 experiments to give a false positive (type I) error). Following that, theories are propounded to explain the mechanism, and then further experiments are performed on those… and so on in order to deepen our understanding (eg. elements -> atoms -> protons/neutrons/electrons -> subatomic particles…etc).
It is not possible to do experiments in an open system. The real causes may or may not be acting, but because the conditions are not controlled (ie. it’s not a closed system) it is not possible to know for sure. Anything that happens may be caused by the thing of interest, but it may also be caused by a million and one other things concurrently acting (or not acting). It’s impossible to tell.
So it may be that CO2 is a greenhouse gas, and that in a closed system (experiment) an increased concentration raises temperatures. This does not mean that it has that effect in an open system, because other forces are acting at the same time.
So the most we can ever say about CO2 (in the open system that is climate) is that an increase in its concentration is correlated with an increase in temperature (if indeed we ignore the last 15 years, and we accept the temperature record as re-re-re-adjusted and reported to 2 decimal places). We may assume that CO2 drives that temperature change but it’s impossible to know for sure because we can’t do any experiments. We can model its effects, but models are not evidence until we can be sure we know all the “million and one other things concurrently acting (or not acting)” — and I would argue we will never know them all.
I think the way the models fail on average to predict the last 15 years’ lack of warming is evidence enough that we should humbly be saying “we don’t know very much” rather than “the science is settled”.
Nancy Green says:
April 4, 2013 at 7:44 pm
Thanks for your excellent work. I look forward to reading more from you.
I’m not really getting it. The Marcott spike is a rubbish end effect so we can’t really infer anything from it (I mean about temperature – perhaps media gullibility, state of climate science…).
Nancy Green,
Your article in the lead post was a significant addition to the increasing knowledge base critical of Marcott et al (2013). Thank you.
However, you undervalue your argument comparing scientific discovery developments in planetary science to Marcott’s research methods when you refer to your comparison as an ‘analogy’.
What you have done is compare the scientific reasoning elements common to two areas of scientific discovery. That is not analogy. It is evaluating epistemic processes in different areas of science..
You exceeded the threshold of lowly analogy and stepped Up into analyzing reasoning in science developments.
Hope to see you again at Anthony’s place.
Note: for years here at WUWT I have been no fan of analogy in science communication. It is not scientific.
John
Robert in Calgary says:
The mass hysteria of CAGW is spread by consensus of the media not by consensus of the scientists. Fear is contagious, calm skepticism is not.
http://xkcd.com/1170/
toto “Even if CO2 emissions completely stop in 2100, the warmth will remain for centuries.”
Please, you have absolutely no idea what will happen to “the warmth” in the future. Even “the warmth” itself is questionable, it’s not at all clear that it’s warmer today than the 1930s — most of the signal is in questionable adjustments to the raw data, and the rest could be explained by siting problems, meaning CO2 may have little to no discernible effect at all.
Werner Brozek:
I am grateful for your post at April 4, 2013 at 3:24 pm but I write to knit-pick. My knit-pick concerns statistical validity. And I make this cavil for the benefit of onlookers because I am certain you know the point I am writing to make.
The issue of the validity of statistically derived information goes to the heart of the subject of this thread. The elegance of Nancy’s analogy is that it explains a point concerning validity of statistically-derived information without need to provide any maths.
Also, I have waited until now before replying to your post because I wanted to be sure Thomas had withdrawn in case this comment induced another dialogue about superstitious nonsense.
Your post says
Actually, your graph addresses a different question to the point I was making. Your graph considers the recent period when the trend has been negative.
As I explained in my post at April 4, 2013 at 2:35 pm, I was considering discernible global warming at 95% confidence. And I wrote
That is true.
So, I reported the period when the global temperature trend is not discernibly different from zero at 95% confidence.
And
You have reported the period where the RSS trend is negative without assessing confidence limits.
I suspect Thomas would find the information you have provided more cogent than the information I stated, so I am grateful for you having provided it. However, readers who understand statistics will recognise that the information I provided has more validity.
Richard
richardscourtney,
Still waiting to hear a reference for your claim that the global temperature rises and falls by 3.8 deg.C twice a year. Thank you.
richardscourtney says:
April 5, 2013 at 3:25 pm
Thank you for your comments. My next post is in the pipeline and I expect it out in a day or two. As with my past posts, I talk about both “no warming” on several data sets and “no significant warming” on the same data sets. The SkS site only goes to the January data for RSS. And for 16 years and 3 months, the slope on RSS is -0.003 ±0.223 °C/decade (2σ). I interpret this to mean that there is a larger than 50% chance there has been cooling for 16 years and 3 months.
And since September of 1989, the trend is 0.129 ±0.130 °C/decade (2σ).
So you could say that at the 95% level, there is no warming for 23 years and 7 months. If the data is updated with February and March, it would either have no affect or it would add a month to this time.
(I must confess to some confusion on this point since is it really 95% or is it 97.5%? Suppose that it said 0.129 ±0.129, would that mean the chances of being above 0.258 are 2.5% and the chances of being below 0 are also 2.5%? And if so, could we then only say that we are 97.5% certain of an increase in temperature since September 1989?)
sceptical says:
April 5, 2013 at 5:39 pm
richardscourtney,
Still waiting to hear a reference for your claim that the global temperature rises and falls by 3.8 deg.C twice a year. Thank you.
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What’s the gag, sceptical? Seasonal variation obviously, you know; gets hot in summer, gets cold in winter. Please don’t come back to cudgel me with some sort of stupidity about how this isn’t global temperature change, I know Richard said global in his original post. It’s got nothing to do with the point he was making about exactly how trivial a 0.8C change really is.
sceptical says:
April 5, 2013 at 5:39 pm
richardscourtney,
Still waiting to hear a reference for your claim that the global temperature rises and falls by 3.8 deg.C twice a year. Thank you.
Hello, Richard may have a different source, but the following is an excellent and recent article that answers this question:
http://theinconvenientskeptic.com/2013/03/misunderstanding-of-the-global-temperature-anomaly/