I have to say this needs even more clarifications, I’m still stuck in the 1930’s (Sorry jshore) I was attempting to refer to the 90’s and after **jshore’s ** #8 post it was clear that this debunking you are talking about remains wishful thinking.
And I did mention Mann was on the record saying that he was overall happy with the NSA commission’s report. However, the quote:
“Overall, the committee believes that Mann’s assessments that the decade of the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis.”
Does not come from the NAS report, it comes form the Wegman report that was set by the politicians to investigate Mann and the Hockey Stick, for that report Mann had an answer:
TESTIMONY OF DR. MICHAEL E. MANN
ASSOCIATE PROFESSOR, DEPARTMENTS OF
METEOROLOGY AND GEOSCIENCES
PENN STATE UNIVERSITY AND
DIRECTOR, PENN STATE EARTH SYSTEM SCIENCE
CENTER
BEFORE THE
SUBCOMMITTEE ON OVERSIGHT AND
INVESTIGATIONS
OF THE
COMMITTEE ON ENERGY AND COMMERCE
[looks at Mann’s testimony]Why should he be if others confirmed his results?
As the New Scientist took a look, and assuming they asked questions, the result in 2007 was to say it is a myth to say the hockey stick was debunked. Unless you can point to current researchers dumping the conclusions this statement of yours is indeed wishful thinking.
I don’t think this means much since the Real Climate piece is titled “Dummies guide to the latest “Hockey Stick” controversy” the reason why I quoted that article was to show other reconstructions also got the Hockey Stick.
And as you are showing here that you are still missing that what the NAS took from Mann they also took from the ones using that data as the definitive evidence to discredit the Hockey Stick.
The more problems you are making of this evidence then the more unreliable are the critics that used that evidence to claim it was hotter on the middle ages. The Hokey Stick does not depend on this data alone.
Already mentioned, and once again you show you are not checking the links.
If you had checked the first post I made, you would had noticed I’m referring to that German high-school teacher curve chart that was used before in an attempt to discredit the hockey stick. However, IIRC that chart of Beck was also posted by you in a previous discussion also looking to discredit the hockey stick. Looking at the points Real Climate mentions, I have to conclude that the ones claiming that the hockey stick was debunked got debunked already.
Sorry, but that’s NOT what you said before. Here’s what you said before:
Bolding added.
Clearly you were implying that the 9 different proxies each independently produce the same (hockey stick shaped?) result. And that just isn’t true.
Anyway, the chart you linked to doesn’t show what the average of the 9 proxy studies is. Not that it would necessarily make any sense to simply average them. It’s not as though there isn’t any overlap.
Some authority stated that at least two of his conclusions were not supported by his analysis. That’s why he would be unhappy. Although most people wouldn’t admit it.
I’ll take that as a “no.” Personally, I doubt that anyone is citing Mann for the proposition that the 1990s were the hottest decade of the millenium.
In which post #?
The fact that you cannot give a coherent answer to my earlier question makes me think that you are probably guilty of both sins.
This thread will last longer (with happier participants) if everyone sticks to wrangling over the data and avoids editorializing on other posters’ modes of participation.
[ /Moderating ]
And you wonder why I think this is now a useless discussion?
To me it is clear a formal debunking of the Hockey Stick requires the climate researchers to look at the evidence and all to refute the research completely, again, the only thing you showed so far is that the Hockey Stick of Mann was amended, the problems with the Bristle cone evidence cuts both Mann and the critics of Mann that rely on this evidence.
It is obvious that the current researchers advised the New Scientist about what was the current state of the Hockey Stick, and the New Scientist looked at the evidence and commission reports, then they published the conclusion that “It is a myth to say the hockey stick was debunked”
Well, since “hockey stick shaped” is a fairly ill-defined term, it is hard to argue precisely if this is true or not. All of them show a pronounced upturn in the temperature in recent times and have the temperatures in the Medieval times lower than they are in the late 20th century. Some of them have a bumpier “shaft” than Mann et al.'s and which is the more correct result is still being debated in the literature. (It is also worth noting that the original Mann graphs had fairly decent-sized error bars so that much of the variation that other studies have found still lie within the error bars of Mann et al.)
As to whether the 1990s was likely the hottest decade and 1998 likely the hottest year, the NAS report said that they felt that this conclusion of Mann et al.'s was the least supportable because they felt there just wasn’t the temporal resolution in all of the proxies to determine something like which single year was the hottest (or even which decade). However, Mann et al. have noted in response to this that they never meant this as a claim based on the resolution of their measurements but rather as a statement based on a combination of their results with statistical arguments. I.e., that the previous warmest general period was enough below the 1990s that it would have been statistically very unlikely to have a decade as warm as the 1990s during that period…and likewise for 1998 as the warmest year. Anyway, this is clearly a point that will generate more discussion and study in the future.
Following common definitions of what a debunking is this discussion is over. The hockey stick was not debunked.
However the only loose item to me that remains, is that it needs to be clarified if the definition of debunking used by the OP is a valid one. If a couple of authorities claim that something was debunked and this is valid, then we might as well say that the idea that “HIV causes AIDS” was debunked when more than a few authorities say so. (sadly, it is true that some authorities do insist on this)
It is clear to me a debunking in science requires the mainstream or the consensus to uphold that debunking.
Well, it doesn’t have a very dramatic a “blade” but the reason is that it ends before most of the recent (late 20th century / early 21st century) warming. If you look at this image, the curve you show (the light green one in this image) seems to agree quite well with the instrumental record at the time that it ends. However, by ending when it does, it misses over 0.4 C of the warming in the instrumental record.
It runs through 1992. Do you have a cite for the claim that the Esper 2002 proxy measurement would have a “blade” if it were extended from 1992 to 2007?
By the way, after thinking about it a little, I would say that the essential aspects of the “Hockey Stick” are as follows:
(1) A temperature reconstruction of the last 1000 years;
(2) Relatively little temperature variation between 1000 and the early 20th century (maximum of 0.5 degrees C from between highest anomaly and lowest anomaly);
(3) A dramatic and relatively steady increase in temperature (perhaps 1 degree C) between the early 20th century and the present; and thus
(4) Temperatures in recent years that are unprecedentedly (in the last 1000 years) high, both in absolute terms as well as in the rate / magnitude of change.
If the Hockey Stick were true, it would certainly support claims of AGW.
If you look at the one picture, you’ll note that the black line is recorded (non-proxy) temperature. Assuming that Esper’s really is a measurement of temperature, it will parallel the actual temperature. If it doesn’t, then it isn’t a measure of the temperature.
Too late to edit: Or, of course, it’s in a wierd location that doesn’t track with the global average very well (the danger with relying on a single source of data.)
It doesn’t look to me like the line really extends to 1992…Maybe it uses data through 1992 but they use this low-pass 40-year filter so they are not getting an average all the way to that year.
As Sage Rat notes, the most recent few decades are best documented by the actual instrumental temperature record.
Hope this doesn’t hijack the thread, but it seemed a good place to ask several GW related questions.
I’ve seen that chart before myself. My question(s) have always been: Was the Medieval Warming Period only considered a local event (i.e. in Europe or in the Northern Hemisphere), or was this a global event? Were the glaciers in Greenland smaller then than today…if not, why was Greenland more habitable then than now? If the glaciers WERE smaller then, was the sea level much higher (I don’t think it was but going from memory)…if not, why not (I assume the answer to this was that the MWP WAS a local as opposed to a global event, but if I knew I wouldn’t need to ask)? What is the level of uncertainty (plus/minus) of the temperature projections before anything before global temperatures were measured in any kind of systematic ways globally using some temperature baseline (Celsius/Fahrenheit)?
Ok…so, initially it WAS apparently viewed as a global phenomena but now ‘this view has been questioned’. Any thoughts on the extent of the questioning and whether this is widely accepted? It says Europe was ‘where the phenomenon was most obvious and clearly documented’…does that mean additional data has come to light?
