The "Hockey Stick" is a chart that shows almost no climate change before the last 100 years. It is a lie.
Source:
http://www.sepp.org/twtwfiles/2021/TWTW%209-4-%2021.pdf
"This TWTW will focus on two additional, significant omissions, in the “Summary for Policymakers” of the Physical Science Basis of Sixth Assessment Report (AR6) by the UN’s Intergovernmental Panel on Climate Change (IPCC).
The Summary for Policymakers (SPM) is used to justify drastic changes in the use of fossil fuels.
Given the magnitude of such changes, the document should be of the highest scientific standards and demonstrate the scientific integrity of the IPCC.
Specifically, a presentation by Stephen McIntyre examining the extent of data, or lack thereof, covering the region of the Southern Hemisphere from 0° to 30° South Latitude will be discussed.
Adding this to last week’s presentation covering the region from 30° to 60° South shows that there is very little data supporting IPCC AR6-SPM assertions that temperatures in this major portion of the globe have been roughly stable for the past 2000 years, until humans began emitting CO2 with the beginning of the industrial revolution, roughly 1850.
McIntyre has traced that the assertions that temperatures have been stable up to the industrial revolution come from a set of studies by an international paleoclimatology group based in Bern, Switzerland, known as PAGES 2k (PAst Global ChangES with 2k referring to the past 2000 years).
This TWTW looks more deeply into this group and perhaps why it has such influence in the IPCC, particularly in that the work is not peer-reviewed, at least publicly, even though the IPCC claims the work it uses is peer-reviewed and publicly available.
... Lacking Data: Steve McIntyre has discussed the studies called PAGES, which are traced to a private international group called Past Global Changes based at the Main Building of the University of Bern, Switzerland.
Using little supporting data, PAGES developed a 2000-year graph supposedly showing little variation in temperatures over time, yet with a significant upswing since the start of the Industrial Revolution.
Roughly a new hockey stick lying horizontally with a sharp upswing in temperatures as the blade.
Previously, McIntyre’s study of the data sources covering the region from 30° to 60° South showed that there is very little data supporting a hockey-stick configuration.
Focusing on the region from 0° to 30° South Latitude, McIntyre shows there are similar data deficiencies.
Most of the data in PAGES studies do not support a hockey-stick configuration.
For those familiar with the history of Mr. Mann’s hockey-stick McIntyre’s introduction is amusing.
He writes:
“In a Climategate email. Keith Briffa famously sneered at Michael Mann’s claim that a temperature reconstruction could represent a hemisphere, including the tropics, by regressing a ‘few poorly temperature respresentative tropical series’ against ‘any other target series’
– even the trend of Mann’s own ‘self-opinionated verbiage’ as follows:
“’I am sick to death of Mann stating his reconstruction represents the tropical area just because it contains a few (poorly temperature representative) tropical series.
He is just as capable of regressing these data again any other ‘target’ series, such as the increasing trend of self-opinionated verbage he has produced over the last few years, and ... (better say no more)’
“People frequently say that the PAGES2K reconstruction has ‘vindicated’ Mannian reconstructions – but neglect to mention that PAGES2K similarly regressed a ‘few poorly temperature representative tropical series’ onto an increasing trend
– thus, repeating, rather than vindicating, (one of) Mann’s erroneous methodologies.
“In today’s article on the Hockey Stick featured in the new IPCC Hockey Stick diagram, I’ll look at proxies in the southern tropics (0-30S latband) [latitude band].
The proxy network turns out to be defective in bizarre, unexpected ways, not reported on or discussed in the original article.”
McIntyre then shows that PAGES has little data dating back 2000 years, and most of the data does not date back before the year 1500.
Thus, the Medieval Warm Period is not covered.
Over the past few years data from other sources have been accumulating that the Medieval Warm Period was a global event, not a regional event confined to Europe as IPCC advocates claim.
McIntyre concludes:
“How the PAGES2K authors obtained a big-bladed Hockey Stick from this data cannot be determined without examining their code, which, to my knowledge, has not been archived.
(Nor have it been provided to me upon tweet request.)
My surmise is that they use some sort of ‘stepwise’ method in which successive steps incorporate the proxies available in that step.
Such techniques will effectively splice the coral blade onto the two non-descript non-bladed long proxies to present a sort of hockey stick.
The failure of the two long proxies to record the proposed blade means that the confidence levels prior to AD1800 or so extend from the ‘floor to the ceiling’ – an apt phrase used by Rosanne d’Arrigo many years ago.
I.e. with this set of information, we know essentially nothing about 0-30S temperatures prior to AD1800 or so.
This does not mean that we actually know nothing.
There are many interesting proxies in the 0-30S latitude band and many fascinating discussions in technical literature that does not appear to be reflected in the IPCC report.
“Consolidating some of the information in this post with my prior post on the 30-60S latband, which consisted almost entirely (~96%) of ocean,
PAGES2K only used one ocean core in the 0- 60S latband, totally omitting high resolution alkenone series.
Only four PAGES2019 series in the 0-60S latband start prior to AD1100 and none of them have a hockey stick shape.
“Overall, I think that it’s fair to say that Briffa’s criticism of Mann remains just as appropriate for the IPCC in 2021, as it did in 2001.
Like Mann’s network, PAGES 2019 ‘contains a few (poorly temperature representative) tropical series’.
And PAGES 2019 authors ‘were just as capable [as Mann] of regressing these data against any other ‘target’ series, such as the increasing trend of self-opinionated verbage he has produced over the last few years’.
Indeed, if anything, the new generation of climate activists have proved themselves more than capable of continuing Mann’s ‘trend of self-opinionated verbiage’ to, shall we say, ‘unprecedented’ levels.
The new hockey-stick is featured in the IPCC’s AR6 Summary for Policymakers, without solid background support in the main document.
As McIntyre shows both the tropical Southern Hemisphere from 0° to 30° South Latitude and temperate Southern Hemisphere from 30° to 60° South Latitude lack data supporting the new hockey-stick.
There is no reason to accept the IPCC AR6 process and its reports as quality science fully backed by physical evidence.
What Are PAGES?
The ability of PAGES graphs to suddenly appear in AR6 Summary for Policymakers, without clear explanation in the main body of the report,
brings up the questions of what is PAGES, how does it get such graphs into AR6 Summary for Policymakers, and who funds it?
Writing in No Tricks Zone, Pierre Gosselin translates and edits a German essay appearing in Die kalte Sonne by an unnamed scientist who is an IPCC 6th report reviewer.
The essay begins:
“The latest UN report distorts climate history.
The tracks lead to Bern, Switzerland.
In the Middle Ages, it was similarly warm in Switzerland and other parts of Central Europe as it is today.
The so-called Medieval Warm Period (MWP) is scientifically well documented in the region:
Between 800 and 1300 A.D., many Alpine glaciers shrank dramatically, and some were even shorter than today.
The tree line shifted upward. Permafrost thawed in high alpine regions that are still firmly in the grip of ice today.
Warm temperatures are also clearly evidenced by tree rings, pollen, chironomid fossils, and other geological reconstruction methods.
“Controversial temperature curve
It had long been assumed that the medieval warmth might be a regional, North Atlantic phenomenon.
However, this has not been confirmed, because the warm phase also occurred in many other regions of the world, for example, on the Antarctic Peninsula, in the Andes, in North America, in the Arctic, in the Mediterranean, in East Africa, China and New Zealand.
Together with professional colleagues, we at Die kalte Sonne have evaluated many hundreds of case studies from around the world in recent years and published the syntheses continent by continent in peer-reviewed journals.
Three of the publications have been cited by the Intergovernmental Panel on Climate Change (IPCC) in its recently published 6th Assessment of the Climate report.
The medieval warmth was then followed globally by a precipitous drop in temperature.
During the Little Ice Age, 1450- 1850, the climate cooled to the coldest temperature level of the entire last ten thousand years.”
After a discussion of Mr. Mann’s hockey-stick in the Third Assessment Report (AR3, 2001) the essay continues:
“Recent paleoclimatological research confirms Medieval Warm Period
In the last two decades, however, paleoclimatology has made great progress, and data have been diligently collected.
From this, more realistic temperature developments were created, with a pronounced Medieval Warm Period and a later Little Ice Age.
All the more bitter now is the relapse into old hockey stick times.
How could this happen?
What were possible motivations behind the renewed distortion of climate history?
“Why back to the hockey stick? PAGES 2k
The questionable new hockey stick temperature curve comes from the international paleoclimatology group PAGES 2k, whose coordinating office is based at the University of Bern in Switzerland.
Climate scientist Thomas Stocker, who has contributed to IPCC reports since 1998, also teaches and conducts research at that university.
In 2015, Stocker even ran for the overall IPCC chairmanship, but lost to South Korean Hoesung Lee, who just presented the 6th Working Group 1 report.
Stocker co-authored the Summary for Policymakers of the IPCC’s 3rd Assessment of the Climate report in which the hockey stick played a prominent role.
“Dissent among the PAGES-2k group
A good twenty years later, the resurfaced field hockey stick now comes from Stocker’s university, where he heads the Department of Climate and Environmental Physics.
Just a dumb coincidence?
There are many indications that the new climate curve may have been a commissioned paper for the 6th IPCC report.
Five of the nineteen authors of the papers on the new hockey stick curve are from Bern.
But a significant portion of the PAGES-2k researchers could not technically support the new hockey-stick version and walked out of the group in dispute.”
As discussed by McIntyre in previous posts, some members of PAGES did not go along with the latest hockey-stick.
The essay continues with how this disgraceful process leads to misleading climate models used in AR6.
The essay concludes:
“Political tactics undermining science
Thus, scientific integrity falls by the wayside.
It is only a matter of time before critical climate scientists systematically address the inconsistencies in the filtered IPCC 6th climate report.
The incident reveals how political tactics are undermining the IPCC’s scientific integrity and further eroding the trust placed in the institution.” ...