How can anyone investigate the hockey stick and not laugh at its ridiculous conclusions?

Question

Is there anyone who has ever studied this report and not laughed their a$$ off? He actually claims to be able to know the temperature (to within tenths of a degree) 500 years ago by studying tree rings? I mean COME ON! Did it ever occur to him that trees only grow during the early spring to summer periods. Or that trees do very little growing in the winter (6 to 7 months out of the year in many parts). Or maybe during a particular year, there was a drought which caused minimal growth, even though temps were high. Or how about the fact that night time (half of most days) is not represented as trees do not photosynthesis without light. Did anyone ever think about this when he first introduced this "ground breaking" report?

So Enraged, you believe that the temperature can be ascertained to within a tenth of a degree over a 900 year period by looking at tree rings? Now that is funny. Maybe you should learn to read?

Eric, thanks for the link. I had read that a while back (yes I do read this stuff) and could not find it.

Enraged,
BTW, you try to make fun of me, yet you give NO evidence to back up your beliefs. Seriously, is that all you have? My 9 year old has better AGW knowledge. ROFL

Answer 1

What is laughable is not that he used tree rings, but his methodology in achieving his results, the fact that he left out data to achieve these results, and the fact that it was accepted by the climate community without question.

Those who want a better explanation can read this article. Notice that he backs up all of his claims with references in scientific journals:

http://www.john-daly.com/hockey/hockey.htm

Answer 2

With all due respect Kristine, might I suggest that you research a little more about the methods that are used to reconstruct historical temperatures.

Some of the points you make are valid - at least they may appear to be on the surface. You state that trees do very little growing in winter, quite correct, but whilst it's winter in one part of the world it's summer in another, whilst there's a drought in place X there could be a flood in place Y, when it's night in one place it's day elsewhere. Throughout the course of a year every part of the planet receives the same amount of night and day.

The dendrochrological record can be extended back by thousands of years and dendroclimatology is just one of many methods that are employed to reconstruct temperatures.

There are limits to the dendroclimatological record but we have developed techniques to minimise these limitations. One such technique is termed 'limiting stands', it's a comparative process that minimises variation within the sample.

By far the best thing to do is to take lots of samples from sites around the planet. Locally there could have been any number of factors that may affect tree growth - soil conditions, altitude, fire, herbivore impact etc etc.

If 10 samples are taken for example and the result is, say 123.456 and then another 10 samples are taken and the result is 123.789 then it's safe to say that the process works. If the second result turned out to be 234.567 then it's clear that something is amiss in which case a further sample would be taken. If that provided a result of 123.321 then it would indicate that the second sample was anomalous or erroneous and it would be discarded and resampled. If however the third result had been 345.678 then it would be clear that the methodology itself was unreliable and the whole thing would be scrapped.

Of course, there are far more than three dendroclimatological datasets. I have no idea of the total number but it's certainly in the hundreds and more than likely in the thousands. With such a huge amount of data to go out any outliers, errors, omissions or other anomalies become apparent and are compensated for or eliminated.

That said, no one tree ring record provides an accurate representation of the climate but by averaging the data from many sets a more accurate picture emerges. It's the same with any statistical analysis - the larger the sample the more reliable the deductions.

Here's a really great thing. We have an accurate instrumental global temperature record going back over 150 years. There is no question that this accurate. The longest cointinual record is one called HADCET which extends back 348 years. What we do is to start at the present day and reconstruct the historical record using dendroclimatology, the results are compared to the known temperatures. If they match then voila, we know the tree ring method is accurate. If they don't match we can tweak the analytical and mathematical solutions until they do. Once we know the process is accurate it can be applied to longer timeframes.

Further, tree rings are just one of many different ways of reconstructing past temperatures. Others include pollen analysis, sedimentary and glacial records, ice core sampling, oxygen isotope analysis etc. The results from these different methods are compared and contrasted.

I'm not saying that these methods are perfect because they're not. The margin of error increases the further back the temperature record is taken, as a rough guide to accuracy the following can be used.

log y ÷ (30 ÷ log y) where y is the number of years

100 years - accuracy ± 0.1°C
1000 years - accuracy ± 0.3°C
10000 years - accuracy ± 0.5°C
100000 years - accuracy ± 0.8°C
1,000,000 years - accuracy ± 1.2°C
10,000,000 years - accuracy ± 1.6°C
100,000,000 years - accuracy ± 2.1°C
542,000,000 years - accuracy ± 2.5°C

542 million years is the furthest we can extend the climate record back because beyond this point the only lifeforms were single celled organisms and so O18 isotopic analysis isn't possible.

Mann's hockey stick is an old graph and not a particularly accurate one. That said, when you overlay the revised graph on top of the original one there really isn't a lot of difference. It's a variation of about 0.2°C relating to temperatures from approx 400 and 1000 years ago - the Little Ice Age and the Medieval Warm Period. Compare the two graphs over the period of the last couple of hundred years, the time for which global warming is applicable, and there's almost no difference.

Since the graph was first produced the science of climatology has developed tremendously. We're learned more since 2000 than in all the time that went before. Inevitably there are updates, revisions, errors etc and when they come to light steps are taken to make the necessary corrections.

I appreciate that you may wish to refute the theory of global warming but it's not all that easy to do. Behind the headlines there's a lot of extremely complicated and sophisticated science, it's the sort of stuff that skeptics (even the 'professional' ones) run away from because it's factual and demonstrable.

If I've failed to explain any of the above points or you just want more information about global warming, climate change or climatology in general please feel free to ask.

Answer 3

Kristine, have you ever studied the subject or have any research experience? Read the documents you allude to; look at some of the scientific literature - the physical science, the potential impacts, the sociological and economic implications; look at the scientific reviews (NAS does a great job with these); then ask yourself "What's wrong with me that I don't understand?"

Most people have the ability to learn.

Answer 4

Kristine, I agree with you completely. The best article on the Hockey Stick was in the Dutch science magazine, Natuurwetenschap & Techniek. You can read the English translation here.

http://www.uoguelph.ca/~rmckitri/research/Climate_L.pdf

I love the part about the CENSORED subdirectory.

The other great things to read are
http://climateaudit.org

and

The Wegman Report and Fact Sheet
http://www.uoguelph.ca/~rmckitri/research/WegmanReport.pdf
http://republicans.energycommerce.house.gov/108/home/07142006_Wegman_fact_sheet.pdf

Wegman is a real statistician, not like Michael Mann.

Note to Bob -
Your statement is completely wrong. While the NAS panel was polite to Mann (much more so than Wegman), they agreed with McIntyre on every important point of science. NAS said Mann's thesis was not supported by the science and that the most that could be claimed is that temps in the late 20th century were warmest in the last 600 years (Mann had claimed there were the warmest in 2,000 years). The NAS panel also agreed with McIntyre that strip bark tree series are not temperature proxies and should not be used in temp reconstructions. They did not look at McIntyre's claim that Mann's approach of decentering the data led to an artificial hockey stick even with trendless red noise used as data, but Hans von Storch and Eduardo Zorita did look at that issue and agreed with McIntyre.

Please read something besides RealClimate before forming your opinions. RealClimate does not have any credibility with real scientists any more. Everyone knows it is owned by a public relations firm.

Answer 5

Well, the National Academy of Sciences treated it with respect. Mann's conclusions were affirmed by the National Academy of Sciences, although they said his statistical methods were not the best.

Since then his work has been duplicated by many scientists using better statistical methods. Ten peer reviewed studies here:

http://www.globalwarmingart.com/wiki/Image:2000_Year_Temperature_Comparison_png

By the way, it was hardly "ground breaking". The tree ring method has been around for a long time, and is widely used.

Answer 6

you know thee is one additional thing that can be done with trees

make me to be bats when bash hippies heads in if this were true then to generally be people to do that a tree would have to be at least 500 and there are only about 5 species world wide that can approach that

Answer 7

Yes, Kristine, I assure you that anything about dendrochronology that has occurred to you occurred to Dr. Michael Mann long, long ago.

Perhaps you ought to spend less time laughing in ignorance at scientists who, in actuality, know much more about the subject than you, and a little more actually, y'know, studying and stuff.