GLOBAL WARMING BOMBSHELL: Hockeystick Broken

MIT Technology Review ^ | 15 October 2004 | Richard Muller

[Yelling]

Well, lets take a look at where we are. You stated that the methodology of Soon was sound. I have presented numerous errors in it. From errors in how he interpreted data, to errors in how his methodology was established and finally to just plain wrong errors (i.e. saying someone said one thing when they clearly said the opposite). Any one of these is enough to doubt a paper. Taken together all three are devastating.

However I agree that he shows some papers that are legitimate attempts at reconstruction. If you want to look at these, great but that is another discussion.

You raise some very good points about stalagmites. Now, did the papers that Soon use follow this?

In regards to research on Cioccale, OK, what is your interpretation of it? I'll dig up a copy tomorrow and we can compare notes.

[palmer]

It's a great time to see where we are. You have poked various holes in the science mentioned in Soon's paper. From there you have decided the paper doesn't pass muster. Your critiques revolving around the use of precip changes to imply support for warming and cooling was pretty good and you had some good specific critiques. Unfortunately nobody was really able to answer those since we all lack the scientific basis to evaluate proxies and especially to control for other factors, notably precip.

However, your decision that the paper has a "devastating" number of errors is meaningless. Unless you have suddenly become a scientific reviewer in the field which doesn't seem to be the case. The purpose of this thread is to attack the hockey stick. That has been successful as you have done little to defend it. You have (to reiterate) raised useful concerns about Soon and others who attack the hockey stick, but you have presented little to support the hockey stick except some repetition of Mann's statistics.

The "complexity" of those statistics (which you first used as a sword and then as a shield) makes it impractical to critique them. But there are two ways in which Mann has been critiqued here:

First you have cast doubt on the use of temperature proxies by everyone but Mann and Mann's use is the weakest of anyone's (let's not get distracted by the 98 paper, it only looks at LIA and the 99 paper is sorely lacking in data).

Second we have presented ample evidence from temperature oriented proxies that the MWP was at least as warm as today. You have poked a few holes in that assessment but have not come close to refuting it. You have yet to provide an indication that there was cooling during MWP to counterbalance the substantial warming observed in N America and Europe. That warming greatly exceeds today's climate and with the addition of other global warming evidence clearly breaks the hockey stick.

[Yelling]

However, your decision that the paper has a "devastating" number of errors is meaningless. Unless you have suddenly become a scientific reviewer in the field which doesn't seem to be the case.

I did not say it had a devastating number of errors. I did say that the errors it did have combined with poor methodology and a lack of understanding of what some of the papers were measuring to provide a devastating combination. Lets be clear. Any paper can have a small error. For example Soon classifies Mann'a 99 paper as a global indication when we have all agreed that it really is a reconstruction of the Northern Hemisphere. That is a minor error.

However saying that a papers shows no climatic anomaly in the 20th century when the paper days that "the warming in recent decades is unprecedented relative to the past millennium." is beyond a minor error!

In regards to how we got onto S&B as opposed to the Hockeystick, again that was not me who changed the topic thread. S&B was presented as a solid piece of research by WOSG (and I believe you liked it the first read through). So I think it is fair of me to examine it.

The "complexity" of those statistics (which you first used as a sword and then as a shield) makes it impractical to critique them.

Impractical! Is that an appeal to ignorance as well? Now I don't feel so bad. However I can agree that we probably would not be able to go much further with Mann.

Instead I would like to address the concerns that you raised in post 140 by presenting the paper Climatic Fluctuations in the Central Region of Argentina in the last 1000 years by Marcela A. Cioccale. I have just given the paper a read and I have found nothing to support a MWP warmer than today. As I said, it has been only a quick read so I am interested in your review.

[palmer]

Instead I would like to address the concerns that you raised in post 140 by presenting the paper Climatic Fluctuations in the Central Region of Argentina in the last 1000 years by Marcela A. Cioccale.

Fine with me. I haven't found the paper so if you have a link please post it.

It's better to debate these source papers than reviews like Mann's or Soon's so we don't get caught up in "what he said" games. I am interested in the facts not in reparsing Soon's words. But try to keep in mind there are a lot of papers representing a lot of climate anomalies including a fair number pointing to warming for MWP equal to or greater than today's. You are more than welcome to point out any that point to less warming or cooling in the MWP anywhere on earth, but naturally those should be source analyses of temperature proxies. In other words reread WOSG's post 101 and answer his points without evading the issue like you did in post #105.

In other words you have yet to show ANY evidence that temperatures were cooler in the MWP anywhere than they are today.

[Yelling]

I could not find a link to it, but I was able to find it in the Quaternary International Journal Volume 62 (1999) pages 35 to 47. It required a quick trip to the library but I was glad of the excuse (I never seem to have enough time for good old fashioned digging in the library these days).

Your comment about me "evading" his questions wounds me deeply and thus requires a detailed response from me. In my opinion, WOSG post the questions as rhetorical since he went ahead and answered them with an reference to S&B. However he did not leave it as simply a reference, he refers to it as the "Authority" (something I believe you might have said about me). He had read Mann, M&M and S&B in the last few days and thought that the S&B paper was the best - to quote him "It's solid". Since he had obviously gotten the three questions from the Soon paper I figured the best start was to show that Soon's paper was not all that he claimed it was. Thus I evaded nothing! Although I do notice that you do love to get the little debating jabs in!

However since you asked directly I will be pleased to answer them.

1) There was a period of warming during the time of the Medieval Warming Period. I believe that it was global but that it was more predominant in some areas such as Europe. That could be somewhat due to our culture's Euro-centric history. However I do not believe that the MWP was as warm as current temperatures.

2) There is no question that there is was a Little Ice Age. The best climate reconstruction that I have come across is a look at Europe based on a 1/2 degree grid (published last year but the name escapes me, I can dig it up if anyone is interested). I was amazed that they could get that fine resolution but they used historical records as well as proxies. However it was only for the last 500 years. They were able to show the LIA on both yearly and how it effected the seasons.

3) Yes and No. I believe that the MWP may well be warmer than the early part of the 20th century, roughly on par with the average temperature of the 20th century and slightly cooler than the recent decades (say 1985 onwards).

In regards to looking for papers that show cooling during the MWP, I don't know of any offhand, but quoting from Cioccale "In the first part of the present millennium, between 1100 and 1400 AD, sometimes called the Medieval Warm Period, the global temperatures rose around 0.3C in comparison to the norm of reference, the year 1900 (Riccardi, 1995)." Of course the current temperature is about 0.5 C warmer than it was in 1900 so that puts the MWP cooler than current times.

[palmer]

"In the first part of the present millennium, between 1100 and 1400 AD, sometimes called the Medieval Warm Period, the global temperatures rose around 0.3C in comparison to the norm of reference, the year 1900 (Riccardi, 1995)." Of course the current temperature is about 0.5 C warmer than it was in 1900 so that puts the MWP cooler than current times.

Averaging 3 centuries to produce one number and comparing that to two decades of above-normal surface temperature measurements (with a well known 0.1 to 0.15 degree bias)?

Comparing a reference year in one study to reference years in others which use different measurements and calculate global average differently? Nice bit of 1900ism there.

There were certainly decades in the MWP that exceeded the extremes of the 1980's and 1990's, that's easy to establish from the long term averages being higher and what we observe about short term variations. You have yet to show a single study showing the MWP was cooler than the 1900's which would call that into question. On the other hand, I and the others have presented global temperatures proxies to show that the MWP was not isolated to the north Atlantic. Yet all you do is blame eurocentrism for the overemphasis on MWP and wave around your non-quantifiable (in terms of temperature offsets) ocean current local effects as the other cause.

On the other hand I admit it is easy to get caught up in Viking stories. But I will keep waiting for your evidence that MWP was cooler than the 1900's comparing averages to averages.

[Yelling]

Averaging 3 centuries to produce one number To be able to say that this is what they did you must have read the paper. So what methodology did they use. Oh, and remember I am actually quoting from the paper that you referred to when you said "I researched the examples you stabbed at above and found it wasn't just glaciers in Argentina (with possible precip influence) but climate compared to today (Cioccale 99)."

[palmer]

There aren't too many ways to get one number, but you are restricted to whatever measurement interval is available in the data. I couldn't find that reference either (Riccardi, 1995) so I don't know how they did their averaging.

But suffice to say it's not thousands of reporting stations worldwide, weighted for area and averaged. Because of that fact, the extremes like 1998 won't show up. You are welcome to point to some error bars and repeat (but not explain) some statistics, and I will try to critique it.

Still waiting for some temperature proxy measurements showing average (about a half century or more) cooler conditions anywhere on earth during the MWP. So far the Vikings are winning.

[Yelling]

I don't know how they did their averaging

An appeal to ignorance? (I have learned something from this discussion.)

Regarding the MWP. The best I can do right now is to refer you to this document. I will note that it is not a peer reviewed paper however in the figure it shows 4 reconstructions of Northern hemisphere temperature (the solid lines). The reconstructions are from peer reviewed journals. Each reconstruction used a different set of proxy data (although there may have been some overlap), different methodologies and different authors. Go wild!

[palmer]

I took a look at the Mann paper and then started looking for the papers he refers to. In the process of searching, I found this data: ftp.ngdc.noaa.gov/paleo/contributions_by_author which has some of the "raw" data used by those authors. I say "raw" because the proxy data has been tinkered with in various ways.

I have looked at 3 so far, jones1998 shows warming anomalies in both hemis from 1960 onwards but the readme says that the 1961-1990 anomalies have been altered in a way I don't understand (yet).

Crowley2000 is also mentioned in Mann's paper and has data that has been thoroughly manipulated using a simulation to remove all forcing effects except those from greenhouse gases. There's no testing of the CO2 forcing hypothesis and therefore no proof of anything.

Evans2002 (mentioned by Soon) only goes back into the LIA, but shows many warmer decades than any in the 1900's. Unfortunately this is based on tree rings and there's no indication of the method used to determine temperature.

I have a lot more work to do, but so far the hockey stick looks like an artifact of assumptions and methodology and is not supported by the raw data.

[palmer]

I believe that the MWP may well be warmer than the early part of the 20th century, roughly on par with the average temperature of the 20th century and slightly cooler than the recent decades (say 1985 onwards).

Briffa1998 (files labeled 2001) was quoted by Soon as showing the 20th century to be warmer than any of the previous 5. The data is interesting though, it shows NH growing season average temperatures from tree rings as having most of that 20th century warmth in the 1930's and 40's.

So this seems to disprove part of your beliefs above, although you will no doubt cling tightly to them.

[Wurlitzer]

bttt

[Yelling]

First, you are quoting Soon's interpretation which, as was shown above, seems to be a little biased and in some places just plain wrong.

Second, even if Soon is correct I am not sure I follow your point here. My comment was about the MWP and your comment is about a data set that covers the LIA.

My comment still stands.

[palmer]

You are obviously not following my point. Soon was quoting the paper as showing anomalous 20th century warming (which is not surprising since the data starts in the LIA). I looked at the raw data and drew my own conclusion which is that the warming is during the 1930's and 40's (with cooling since). Your comment was this:

I believe that the MWP may well be warmer than the early part of the 20th century, roughly on par with the average temperature of the 20th century and slightly cooler than the recent decades (say 1985 onwards).

The data shows that there was warming in 1930's and 1940's. Your comment is at least leaning heavily.

[Yelling]

Crowley2000 is also mentioned in Mann's paper and has data that has been thoroughly manipulated using a simulation to remove all forcing effects except those from greenhouse gases. There's no testing of the CO2 forcing hypothesis and therefore no proof of anything.

Umm, I think that you may have gotten your papers mixed up. The one that Mann referenced is "How Warm Was the Medieval Warm Period?" by Crowley and Lowery .

The one that you found the data set on was "Causes of Climate Change Over the Past 1000 Years" by Crowley alone.

[Yelling]

But there has not been cooling since. There was a period of very slight cooling about 1940 - 1980, followed by a greater increase of warming. The warming since 1980 has been about 0.4C, lots of room for a MWP.

[palmer]

Nonetheless, it is likely that Crowley used the same data tweaking in both papers. The dataset I downloaded is tweaked and can't be used to compare current proxy measurements with past ones. I'll keep downloading data sets and posting conclusions for all the ones I download no matter what the results, but I can't draw conclusions when data has been manipulated.

[palmer]

0.4 C warming (subtracting the 0.1 to 0.15 degree measurement bias) is hardly unusual in the climate record. If you look at ANY of the raw data (untweaked) you will see one or two decades of dramatic warming all over the place including the LIA.

[Yelling]

Nonetheless, it is likely that Crowley used the same data tweaking in both papers.

LOL

That is a new argument, an appeal to probability.

Go ahead and do your analysis, but please try to make sure that you actually reference the correct papers this time.

Until then.

Y.

[palmer]

The dataset is from Crowley's paper, but it is the Crowley-Lowery dataset. That's what it says in the readme file. My appeal to probability seems sound in this case.