The hockey stick issue is important for several reasons:

1) it is inconsistent with all the individual regional proxies which show many different regions on various continents warmer than today at some point in the MWP - if relatively high global temp wasn't the cause, what was?

2) many of the Detection & Attribution Studies which are hailed as some of the most compelling evidence for AGW depend on millennial temps having a hockey stick shaped trend because this means 20th Century temps are unusual and you need an unusual factor like AGW to explain it. I have argued this before http://www.usefulinfo.co.uk/climate_change_global_warming.php#weakness3

Without the hockey stick, all these studies are just fiction and the scientists who produced these studies look foolish and it shows what flimsy evidence these Detection & Attribution Studies are, a point that I have made. They are not the 'compelling' evidence as stated but simply a climate model study.

3) the enthusiasm with which the IPCC adopted the hockey stick and the emphasis placed on it in the TAR and the subsequent criticism of MBH99 and recognition that it underrates millennial temp variability by a FACTOR OF TWO brings into question the wisdom and objectivity of the scientists/IPCC.  How do we know when we can trust the statements of the IPCC on climate change?

Ferdinand

might be it's just about words and we are agreeing on the physics, but when you say "mechanism x is or is not implemented in a GCM" that means for me that you are speaking of a physical mechanism, e.g. the influence of aerosols on clouds can be described in clear physical terms. Something like "the correlation between e.g. seaice and artic cloud cover or between TSR and clouds CANNOT be implemented but (if shown relevant and robust) can only be verified in the GCM. Are we agreeing on that? GCM include only physics not any kind of periodicity/correlation/etc.

Again. See above. It's not like GCM work. 

TSI records from proxies or direct observation are NOT ( taking whatever time lag) describe satisfyingly 20th century temperature trends. Given the now 30 year long stagnacy of TSI we should - if you were right - see a near-constant global temperature evolution. Good that at least this question will be decided still in our lifetime (hopefully).

Which leaves you in the somewhat inconfortable situation that over 8000 years your solar activity is nearly completely shadowed by other factors, but right now when Greenhouse gases rise and there were people telling you that this rise is having an important impact on climate, solar activity takes over and becomes dominant. Hmmm.

Georg 

Is this uniqueness a genuine difference? Or is it because today we have weather stations recording temperature all over land surfaces and satellites reording SST so we have vast amounts of info today compared with the MWP when we have have very sparse data and what is available is proxy -based therefore unreliable relative to thermometer data.  

Some data do indeed indicate that the MWP is global. There is the global borehole data of Huang & Pollack 1997 which show a MWP about 0.6 C warmer than today.

Huang, S., Pollack, H. N., and Shen, P.Y., 1997. Late Quaternary temperature change seen in world-wide continental heat flow measurements. Geophys. Res. Lett., 24: 1947-1950

There is probably more but it won't be quoted as it conflicts with MBH99.

Returning to the individual regional proxies from different continents which show temps at times in the MWP higher than in the LIA and 20th century. As you say, these exceptional warm ones are cancelled out apparently by equally anomalous cold ones giving very marked regional heterogeneity. Is this a genuine phenemonen (and if so, what could have caused it? I note Georg that you have no suggestions) or is it the result of proxies being unreliable measurements of temperature? I think some proxies are much better measures of temp than others and if you analyse good & bad ones together, you get a result like MBH99 showing a MWP cooler than today.  Indeed Von Storch et al 2004 showed that MBH99 was flawed for the following reasons:

1. the fact that variations in proxy data are caused by other factors in addition to temperature reduces the variance in the temperature reconstruction
2. a lack of variation in temperature in the period which is used to calibrate the proxy data to temperature greatly reduces variance in the temperature construction
3. the lack of data from large regions of the northern hemisphere is also contributing to the reduced variance in Mann et al (1998)

Von Storch, H., Zorita, E.,  Jones, J., Dimitriev, Y., Gonzalez-Rouco, F. & Tett, S. (2004). Reconstructing Past Climate from noisy data. Science, 306, 679621.

So we know that there are problems with the averaging techniques whci result in a MWP cooler than today and the view of the IPCC should reflect this. But they adopted MBH99 with enthusiasm.

Both the Crowley paper & Hegerl at al used various paleoclimate reconstructions over the last 1000 years.

http://www.nicholas.duke.edu/people/faculty/hegerl/2002gl016635.pdf

And there are others. But I agree for the Detection & Attribution studies using the instrumental data for the last 150 years,the HS is irrelevant. For the remainder, the HS is not irrelevant and these papers are flawed if the last millennium did not have a hockey-stick shaped temp trend.

We agree on something Georg. [yes]

Yes the IPCC was wrong to adopt the HS with such enthusiasm and yes I'm sure a lot of the science presented by the IPCC is sound and uncontroversial. But the problem is that how can I or anyone know when the science is good and when it is poor like the HS. There are other areas in addition to the HS where I don't trust the IPCC view:

1) that most global warming over the last 50 years is due to human activities - judging from the rise of global temp in the 1980s & 1990s and the stalling post 1998, it is obvious that internal climate variability eg El Ninos & other factors are dictating global temp variations

2) the claim that anthropogenic sulphates caused the mid-20th century cooling - they couldn't cause a global effect and it is obvious that PDO, SOI & NAO were the main cause for this global cooling

These are the main two areas where I don't trust the IPCC view and the HS issue of course has big implications for natural variability. I don't accept that a 1 C rise since the LIA is an exceptional global temp rise and a reason for alarm. It is within natural variability.  The individual regional proxies show a massive amount of climate varibility within regions which eclipses or equal any temp change regionally in the 20th century. Take the CET over the last 300 years showing a warming of about 1 C, there are countless paleoclimate studies showing much greater warming or cooling regionally than 1 C. What is the big deal about current climate change? It is not exceptional, it is all hype and alarm and possibly the biggest example of mass hysteria the world has ever known.

Ah, it doesn't make Von Storch look good does it. But there is plenty more criticism of MBH99 and the reconstructions which show much more variability than MBH99 (eg Moberg) and there is of course the global borehole data showing a warmer MWP than today.

And of course, a MWP cooler than today doesn't prove AGW and a MWP warmer than today doesn't disprove it. This is all a sideshow to the science of AGW. But the arguements are endless and I feel can't be resolved as we have no thermometer data for the MWP.

I think comparing regional proxies from the last millennium with regional temp of the 20th century is a much more fruitful way of working out if current climate change is anomalous compared with the past.  This averaging of lots of dodgy proxies can only ever produce a dodgy global temp record. And I suspect if you do this, recent regional warming will not stand out as anomalous compared with the past. I am working on an article looking at this.

You can try to distribute on the following map proxy sites which give you a similar heterogeneous pattern as for the MWP. Quite tricky.

Because the secret Greenhouse Warming mafia sends professional killers ?

Because each time when one of the rare courageous climate scientists tries to cite these existing but uncited results looses his jobs, credit card numbers, bank account, and dirty stories about their private life are published in the Sun?

Well, the IPCC2001 couldnt reflect von Storch 2004 and so let's wait what the new IPCC says about all that (I know it, but I am not allowed to speak).

Well we agreed even on more: That in fact there is virtually (have to read the Crowley paper to see if I would call it an attribution study) no attribution/detection studies based on the HS and so it's of no importance for this part of IPCC claims.

That's plain wrong. For example look for ENSO pattern in the upper graph. Same for your second claim. These patterns dont have the right spatial/temporal structure. That was an easy one.

The big deal is its globally uniform structure, its amplitude and its timing. "The biggest mass hysteria the world has ever known". Just in front of lets say Orson Welles "War of the worlds" radio emission and Joseph Goebbels speach in Berlin's Sportpalace? I am extremely interested in your personal list of greatest mass hysteria ever. Give me the top ten.

Yes it is very odd this lack of publications which show the MWP to be regionally cold. I don't know of a single one. And what also is absent is any theory to explain how such anomalous cold & warmth existed at the same time.

Now Rossby waves do explain why some regions can be warm while others are cold but Rossby waves don't explain why so many regions were so anomolously warm in the MWP (which we know to be true) nor do they explain why some regions were so anomaloulsy warm and others were so anomalously cold (which is not supported by publications) at the same time.

Or perhaps Rossby waves can explain this assuming that in the MWP, they had higher amplitude than today's Rossby waves. But I have never seen any attempts to explain how this MPW climate of regional contrasts occurred, how it was supported meteorologically. Perhaps Georg would like to expain the theory behind this strange MWP climate and provide some links to support his theory?

"The Truth Is Out There" !!!

Andre you all seeing wizard you. Tell me the TRUTH. You clearly are the chosen one who knows all!

Being more serious.

A site/article/report (like the link on your post) that states alot of quotes of people who clearly know nothing about science, who infact state alot of nonsense. Does not a conspiracy make.
Do the media do this, yes quite alot and about so very many subjects. One can easily spot this when the news story crosses a subject known by oneself.
But what you are noticing is not some mass conspiracy of powerful world dominating climate scientists but cr*p journalists quoting or reporting people who haven't got a clue.

The proof is in the pudding mate. Nothing is actually being done, in real terms, to reduce anthropogenic impact on planet Earth. So in reality this supposed "climate change mafia" have done nothing at all.

JohnF

Good grief oh great one, don't you read the links you post? 

http://www.sepp.org/NewSEPP/StateFear-Deming.htm

Opening 7 paragraphs!

Including the momentous personal discovery that the media are not subject to the rules of objective rational discussion. 

"It was my first realization that the media intentionally filter the information the public receives."

Blimey he's observant! (though they filter as much from ignorance as from any agenda the editor/owner might have)

JohnF 

1) I did not notice Dr Mann answering questions on the NAS panel sessions, which was a scientific forum COMPLETETELY dedicated to his publications. He didn't even bother to attend the early speakers.

2) Luterbacher posted on RC AFTER my webpublication.

Georg,

Good that you mention clouds... These are implemented in GCM's based on parameterizations, not on physics. And are far from perfect in the tropics (and up to 60N-60S, see Allan & Slingo) and in the Arctic (see Cicero):

And maybe in the rest of the world, but there it doesn't change the radiation balance significantly.

And what about (sulfate) aerosols? As far as I know, the physical and chemical processes making stratospheric aerosols (from volcanoes) and tropospheric aerosols (from human/natural sources) are not different, only the formation and residence times are quite different (2-3 years against average 4 days). This means that the temperature reduction by human-made aerosols is not more than 0.025 K (based on 0.6 K - including water vapor feedback - from the Pinatubo). Current GCM's implement 1 W/m2 (or 0.3 K in equilibrium) for aerosols. Where is that based on? Not to be forgotten the secondary/tertiary effects of aerosols (brighter and longer lasting clouds), but in the (sub)tropics, the area of increasing SO2 emissions (SE Asia), there are less clouds and albedo is decreasing...

Thus, if problematic clouds and aerosols are included in current GCMs, why shouldn't  the observed trend in cloud cover/TSR be included in GCM's as a fortifying factor for the long-term solar irradiation trend? Even if the exact physical process is not known? Over two sun cycles there is a highly significant inverse correlation between low cloud cover and TSR.

Although short-term cycles (ENSO, 11/22 year sun cycles) don't need to be reproduced by GCM's, other medium-to-long cycles (AMO, over 50 year sun cycles) should be included (even if difficult, as these are not exact predictable cycles), or one can find the GCM's in deep trouble (is already the case for short-term cycles, but that is less important, except if one bases projections on a too short time base). 

I suppose that there will be more clarity in the next 10 years (except if the next solar cycle - as predicted! - would be very active)...

According to the Hadcm3 model, the "optimum" results of their model (within all constraints of the model) give a 50% attribution of solar to the 1900-1950 temperature rise, and a 10-30% (depending of the solar reconstruction) for the second halve of the past century. If solar is underestimated (by a factor 2 or so), then there is not much left for GHGs in the first halve and 40-80% in the second halve... Thus there is a high probabilty that increasing GHGs have an influence. The remaining problem is that even for the second halve, the overlap between GHG warming and solar warming is quite substantial, which makes it difficult to attribute the right values to the right forcing.

Besides that, even internal oscillations (AMO) can give huge changes in ocean heat storage/SST/SAT, not related to GHGs and/or solar.

Ferdinand

Reality check? You are kidding.

To confirm the map take the 6000 stations, do a proper homogenization and you will find the same. It's one of the most unbased claims of sceptics comparing single unhomogenized records with grid point values. Yawn.

andre - 1/5/2006 22:10

Georg Hoffmann - 1/5/2006 19:29

 

You can try to distribute on the following map proxy sites which give you a similar heterogeneous pattern as for the MWP. Quite tricky.

How about a little reality check?

 

 

Apparantly the range of the temperature is very well chosen to show a significant start point and point bias if at all accurate. But on some longer term, trends look pretty different.

 

A potential MWP definetly does not look this (based on the existing data) but for any 30-50year period you find lots of cooling signals as well.

 

I see your single cooling signal and raise you 25 hot spots.

Mmmmm, nice yummy cherries