Sentences with phrase «hockey stick reconstruction of»

(The seabed reconstruction confirms the famous 1999 hockey stick reconstruction of temperatures since the year 1000, which mostly used tree rings).

One would be hard - pressed, however, to distinguish their new series from the decade - and - a-half-old Hockey Stick reconstruction of Mann, Bradley and Hughes.»

The leaker (s) released an additional 5,000 emails involving the same cast of characters, notably Phil Jones of the Climatic Research Unit (CRU) at the University of East Anglia, and Michael Mann, creator of the discredited Hockey Stick reconstruction of Northern Hemisphere temperature history.

The problem is that when the modern energy balance models, such as the Foukal's one, are run on 1000 years they give a result that is compatible with the hockey stick reconstruction of Mann and Jones.

Not exact matches

A graph of the warming trend largely replicates the so - called «hockey stick,» a previous reconstruction that showed relatively stable temperatures suddenly spiking upward in recent history.

Most later temperature reconstructions fall within the error bars of the original hockey stick.

Michael Mann, a climate researcher at Pennsylvania State University in State College, is perhaps best known for his work on the «hockey stick» reconstruction of past climate.

McIntyre and his collaborator Ross McKitrick made it their mission to get rid of anything resembling a hockey stick in the MBH98 (and any other) reconstruction of past temperature.

If more or less all reconstructions end up delivering some manner of a hockey - stick shape, then why not simply go with the reconstructions that satisfy both conditions of robustness, considering the first one is just about always met..?

The chief focus is the original hockey stick, a reconstruction of past temperature for the northern hemisphere covering the last 600 years by Mike Mann, Ray Bradley, and Malcolm Hughes (1998, Nature, 392, 779, doi: 10.1038 / 33859, available here), hereafter called «MBH98» (the reconstruction was later extended back to a thousand years by Mann et al, 1999, or «MBH99»).

I was somewhat involuntarily thrust into the center of the public debate over climate change at this very time, when the «Hockey Stick» temperature reconstruction I co-authored, depicting the unprecedented nature of modern warming in at least the past millennium, developed into an icon in the debate over human - caused climate change [particularly when it was featured in the Summary for Policy Makers (SPM) of the Third Assessment Report of the IPCC in 2001].

It just so happens that all of the reconstructions that pass these tests (though with skill that decreases in back in time) show hockey stick like features.

The «hockey stick» reconstruction of temperatures of the past millennium has attracted much attention — partly as it was high - lighted in the 2001 IPCC report as one of the important new results since the previous IPCC report of 1995, and partly as it has become the focus of a number of challenges.

These results are bound to stir up interest beyond the scientific community, since the «hockey stick» shape of previous reconstructions has become so totemic (although just about everyone agrees that there is no need for this «totemising».

In fact, this conclusion is from the 1995 IPCC report, and thus predates the existence of quantitative proxy reconstructions like the «hockey stick».

These results are bound to stir up interest beyond the scientific community, since the «hockey stick» shape of previous reconstructions has become so totemic (although just about everyone agrees that there is no need for this «totemising»).

The validity of the so - called «Hockey Stick» can, of course, neither rest on the strength of MBH98, nor any one reconstruction or model simulation result alone.

Our temperatures are not unprecedented and the Hockey Stick is a proven lie as are all the other reconstructions which attempt to resurrect it because they rely on at least one of the infamous proxies used by Mann.

We already demonstrated the falsehood of this assertion here by showing (a) that the hockey stick pattern emerges using either the MM (centered) or MBH98 (non-centered) PCA conventions, but was censored by MM through an inappropriate application of selection rules for determining the number of Principal Component (PC) to retain, (b) that use of the correct number of PC series (5) to be kept with the MM (centered) convention retains the characteristic «Hockey Stick» pattern as an important predictor, and yields essentially the same temperature reconstruction as MBH98, and finally More&hockey stick pattern emerges using either the MM (centered) or MBH98 (non-centered) PCA conventions, but was censored by MM through an inappropriate application of selection rules for determining the number of Principal Component (PC) to retain, (b) that use of the correct number of PC series (5) to be kept with the MM (centered) convention retains the characteristic «Hockey Stick» pattern as an important predictor, and yields essentially the same temperature reconstruction as MBH98, and finally More&rstick pattern emerges using either the MM (centered) or MBH98 (non-centered) PCA conventions, but was censored by MM through an inappropriate application of selection rules for determining the number of Principal Component (PC) to retain, (b) that use of the correct number of PC series (5) to be kept with the MM (centered) convention retains the characteristic «Hockey Stick» pattern as an important predictor, and yields essentially the same temperature reconstruction as MBH98, and finally More&Hockey Stick» pattern as an important predictor, and yields essentially the same temperature reconstruction as MBH98, and finally More&rStick» pattern as an important predictor, and yields essentially the same temperature reconstruction as MBH98, and finally More»

And, just as the original Mann et al «hockey stick» was followed by additional work leading to the «spaghetti diagram» of the IPCC in 2007 showing numerous similar reconstructions, with a robust common signal, we can expect that this new paper will for now serve as the standard, but will stimulate additional studies that motivate even stronger conclusions.

Can any conclusion regarding future climate change be drawn from the «hockey stick» reconstruction, and can any level of statistical confidence be placed on the conclusion?

It turns out that the proxy reconstructions were done by the SAME group of scientists who did the first hockey stick.

These other reconstructions do tend to show some more variability than MBH98, ie the handle of the hockey stick is not as straight, but they * all * support the general conclusions that the IPCC TAR came to in 2001: the late 20th century warming is anamolous in the last one or two thousand years and the 1990's are very likely warmer than any other time in the last one or two thousand years.»

One thought that occurred to me while reading this entry is how critical evaluation of millennial reconstructions in general, and criticisms of the hockey stick specifically, are often attributed to specific events or dates that represented a watershed moment.

The «hockey stick» describes a reconstruction of past temperature over the past 1000 to 2000 years using tree - rings, ice cores, coral and other records that act as proxies for temperature (Mann 1999).

In our understanding, McIntyre has raised two objections to the hockey - stick reconstruction; one was the statistical problem just mentioned, the other the selective selection of proxy data (the bristlecone question).

I also note that I have had a shot at the hockey stick at the basic level of whether tree rings are even valid as a proxy for long term temperature reconstruction (Loehle, C. 2004.

In October 2004 we were lucky to publish in Science our critique of the «hockey - stick» reconstruction of the temperature of the last 1000 years.

At the EGU General Assembly a few weeks ago there were no less than three papers from groups in Copenhagen and Bern assessing critically the merits of methods used to reconstruct historical climate variable from proxies; Bürger's papers in 2005; Moberg's paper in Nature in 2005; various papers on borehole temperature; The National Academy of Science Report from 2006 — al of which have helped to clarify that the hockey - stick methodologies lead indeed to questionable historical reconstructions.

In fact, Marohasy points out that a lack of rising temperatures for recent decades is so common in paleoclimate reconstructions that tendentious climate scientists have necessarily added heavily adjusted, hockey - stick - shaped instrumental records (e.g., from NASA GISS, HadCRUT) on to the end of the trend so as to maintain the visualization of an ongoing dangerous warming.

Amazingly enough, Mann now admits his original hockey stick existed solely because of «one set of tree ring records,» directly contradicting his 1998 paper which said the reconstruction was «relatively robust to the inclusion of dendroclimatic indicators» (dendroclimatic indicators are tree ring data).

In that paper, we discussed all 19 of the proxy - based global temperature reconstructions of the last millennium, including the Mann «hockey stick».

-LSB-...] Freedom of Information Act request for thousands of emails from Dr. Michael Mann, creator of the disputed «hockey stick» reconstruction of historical global temperatures.

The NAS said» Mann et al. used a type of principal component analysis that tends to bias the shape of the reconstructions», i.e. produce hockey sticks from baseball statistics, telephone book numbers, and monte carlo random numbers.

«Mann and his co-authors created a temperature reconstruction of the past 1,000 years (of the northern hemisphere) which had the shape of a «hockey stick.»

Role: McKitrick was among the first to take a swipe at the famed «hockey - stick graph,» a reconstruction of temperature in the Northern Hemisphere for the past 1,000 years that has been featured prominently by the Intergovernmental Panel on Climate Change (IPCC), and in Al Gore's movie An Inconvenient Truth.

Of course we do nt want to use any tree ring series that does nt show a hockey stick in the instrumental period for temperature reconstructions, because they do nt exhibit increased growth with increased temperature.

If the paper had used the actual confidence intervals of the reconstructions, there would be a plus or minus 1.5 C gray cloud that would have buried that hockey stick.

He (McIntyre) was able to demonstrate that the way they had extracted the temperature signal from the tree ring records was biased so as to choose hockey - stick shaped graphs in preference to other shapes... He also showed that the appearance of the graph was due solely to the use of an estimate of historic temperatures based on tree rings from bristlecone pines, a species that was known to be problematic for this kind of reconstruction.

Climategate had a profound affect in that it made clear the cabal at the centre of the hockey stick and temperature reconstructions were not to be trusted.

The biggest problem with what appears here is in the handling of the greater variability found in some reconstructions, and the whole discussion of the «hockey stick».

Please see this article for a different take on the (not new, BTW) Hockey Stick controversy, there are dozens of other reconstructions that have supported the same conclusions.

[The] fact that their paper fit some policy agendas has greatly enhanced their paper's visibility... The «hockey stick» reconstruction of temperature graphic dramatically illustrated the global warming issue and was adopted by the IPCC and many governments as the poster graphic.

Gavin Schmidt's comment on RC to the effect that he didn't care what the temperature was 1000 years ago is sufficient to realise that defence of the Hockey Stick has been abandoned — palaeo reconstructions are now regarded as irrelevant

Briffa uses just 12, then 10 and then 5 trees to form the hockey stick portion of his reconstruction.

As related in USA Today, the investigation followed a formal complaint by paleoclimatologist Raymond Bradley, co-author of the seminal (and controversial) 1998 and 1999 «hockey stick» temperature reconstructions.

The REAL issue with regard to «the hockey stick» as well as far too much of what is presented as «climate science» is in the opinion - centric attention to «temperature reconstructions», erroneous in their «fabricated production» with included methodology to produce «a temperature proxy» that is NOT relating Kinetic Energy representative OF the «temperature» of those materials presenof what is presented as «climate science» is in the opinion - centric attention to «temperature reconstructions», erroneous in their «fabricated production» with included methodology to produce «a temperature proxy» that is NOT relating Kinetic Energy representative OF the «temperature» of those materials presenOF the «temperature» of those materials presenof those materials present.

We have seen above that one of the chief criticisms of the hockey stick was the fact that its author, Michael Mann, had withheld the validation statistics so that it was impossible for anyone to gauge the reliability of the reconstruction.

Mr. Watts, while you are presenting this new study by Melvin et al. as something that provides results which allegedly refute Mann's hockey stick you do not tell your audience here that the temperature reconstruction shown in the graph, explicitly mentioned by you here, in the Melvin et al paper is done only for a region of Northern Scandinavia, unlike the temperature reconstruction in Mann et al., (1999), doi: 10.1029 / 1999GL900070, which was a reconstruction of the Northern Hemispheric temperature.

With this new, and pretty much entirely arbitrary hurdle in place, Wahl and Amman were able to reject several of the runs which stood between the hockey stick and what they saw as its rightful place as the gold standard for climate reconstructions.