To clarify that last sentence. Yes, we have record temperatures by hundredths of a degree if you think that the statistics and the measurements and the massaged temperature datasets make any of this meaningful. But, of course our records only go back a century in most cases. As a species, we have several thousand years of relevant climate to think about.

Some say that the MWP was much warmer than today. There is evidence that we farmed in Iceland in Roman times. It is true that carbon dioxide was much higher at times in our history too.

Schrodinger's cat

Given unlimited choice of start date, finish date and time period you can find very high positive and negative rates of change in the record, up to 0.4C/decade in either direction.

What objective methods do you suggest to avoid bias when two periods in the record are compared?

How was it done in your field?

Let us step back a little. The imperative to prove catastrophic rates of warming is driven by a political agenda. If we look at the data it is as we have shown. The justification is there if you cherry pick, not if you don't and the opposite conclusion if you cherry pick the other way.

Scientists should simply say that it is inconclusive. There is risk, etc. More time (data) is needed to see what happens next. That is the honest scientific conclusion for this particular point.

Why should scientists try to invent conclusions based on inconclusive data?

Science does not do incontrovertible proof, as you should know.

Nov 22, 2017 at 7:30 PM | Entropic man

This is science not theology.

In the absence of proof, or even evidence that a problem exists, why should taxpayers have to foot the bill? The Precautionary Principle is getting rather expensive.

EM,

A lot of money has been spent. If Climate Science still has no evidence, shouldn't we assume that nothing much has changed, and the climate continues to warm and cool for reasons that remain unexplained?

Clip[e]

Golf Charlie has already put up that link twice.

We have discussed its shortcomings already.
Nov 20, 2017 at 10:20 AM | Unregistered CommenterEntropic man

I'm not going to read, notice or remember every comment out of 900 and counting....but what is meant by "shortcomings"?

shortcomings with regards to "that link".

At this point I did a big skip forward to 2003. En route I passed over the already famous 0942777075, in November 99, in which Phil Jones says, 'I've just completed Mike's Nature trick of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) amd from 1961 for Keith's to hide the decline.'

Sorry, the above is excerpted from

https://web.archive.org/web/20120108014900/http://michaelkelly.artofeurope.com/cru.htm

Hide the decline

From: "Chris de Freitas" <c.defreitas@auckland.ac.nz>
To: Inter-Research Science Publisher
Date: Wed, 18 Jun 2003 13:45:56 +1200
Subject: Re: Climate Research
Reply-to: c.defreitas@auckland.ac.nz
CC: m.hulme@uea.ac.uk
Priority: normal
X-mailer: Pegasus Mail for Win32 (v3.12c)
Otto (and copied to Mike Hulme)
I have spent a considerable amount of my time on this matter and had
my integrity attacked in the process. I want to emphasize that the
people leading this attack are hardly impartial observers. Mike
himself refers to "politics" and political incitement involved. Both
Hulme and Goodess are from the Climate Research Unit of UEA that is
not particularly well known for impartial views on the climate change
debate. The CRU has a large stake in climate change research funding
as I understand it pays the salaries of most of its staff. I
understand too the journalist David Appell was leaked information to
fuel a public attack. I do not know the source
Mike Hulme refers to the number of papers I have processed for CR
that "have been authored by scientists who are well known for their
opposition to the notion that humans are significantly altering
global climate." How many can he say he has processed? I suspect the
answer is nil. Does this mean he is biased towards scientists "who
are well known for their support for the notion that humans are
significantly altering global climate?
Mike Hulme quite clearly has an axe or two to grind, and, it seems, a
political agenda. But attacks on me of this sort challenge my
professional integrity, not only as a CR editor, but also as an
academic and scientist. Mike Hulme should know that I have never
accepted any research money for climate change research, none from
any "side" or lobby or interest group or government or industry. So I
have no pipers to pay.
This matter has gone too far. The critics show a lack of moral
imagination. And the Cramer affair is dragged up over an over again.
People quickly forget that Cramer (like Hulme and Goodess now) was
attacking Larry Kalkstein and me for approving manuscripts, in
Hulme's words, "authored by scientists who are well known for their
opposition to the notion that humans are significantly altering
global climate."
I would like to remind those who continually drag up the Cramer
affair that Cramer himself was not unequivocal in his condemnation of
Balling et al's manuscript (the one Cramer refereed and now says I
should have not had published - and what started all this off). In
fact, he did not even recommend that it be rejected. He stated in his
review: "My review of the manuscript is mainly with the conclusions
of the work. For technical assessment, I do not myself have
sufficient experience with time series analysis of the kind presented
by the authors." He goes on to recommend: "revise and resubmit for
additional review". This is exactly what I did; but I did not send it
back to him after resubmission for the very reason that he himself
confessed to ignorance about the analytical method used.
Am I to trundle all this out over and over again because of criticism
from a lobbyist scientists who are, paraphrasing Hulme, "well known
for their support for the notion that humans are significantly
altering global climate".
The criticisms of Soon and Baliunas (2003) CR article raised by Mike
Hume in his 16 June 2003 email to you was not raised by the any of
the four referees I used (but is curiously similar to points raided
by David Appell!). Keep in mind that referees used were selected in
consultation with a paleoclimatologist. Five referees were selected
based on the guidance I received. All are reputable
paleoclimatologists, respected for their expertise in reconstruction
of past climates. None (none at all) were from what Hans and Clare
have referred to as "the other side" or what Hulme refers to as
people well known for their opposition to the notion that humans are
significantly altering global climate." One of the five referees
turned down the request to review explaining he was busy and would
not have the time. The remaining four referees sent their detailed
comments to me. None suggested the manuscript should be rejected. S&B
were asked to respond to referees comments and make extensive
alterations accordingly. This was done.
I am no paleoclimatolgist, far from it, but have collected opinions
from other paleoclimatologists on the S&B paper. I summarise them
here. What I take from the S&B paper is an attempt to assess climate
data lost from sight in the Mann proxies. For example, the raising on
lowering of glacier equilibrium lines was the origin of the Little
Ice Age as a concept and still seems to be a highly important proxy,
even if a little difficult to precisely quantify.
Using a much larger number of "proxy" indicators than Mann did, S&B
inquired whether there was a globally detectable 50-year period of
unusual cold in the LIA and a similarly warm era in the MWP. Further,
they asked if these indicators, in general, would indicate that any
similar period in the 20th century was warmer than any other era.
S&B did not purport to do independent interpretation of climate time
series, either through 50-year filters or otherwise. They merely
adopt the conclusions of the cited authors and make a scorecard. It
seems pretty evident to me that temperatures in the LIA were the
lowest since the LGM. There are lots of peer-reviewed paleo-articles
which assert the existence of LIA.
Frankly, I have difficulty understanding this particular quibble.
Some sort of averaging is necessary to establish the 'slower' trends,
and that sort of averaging is used by every single study - they
average to bring out the item of their interest. A million year
average would do little to enlighten, as would detailed daily
readings. The period must be chosen to eliminate as much of the
'noise' as possible without degrading the longer-term signals
significantly.
As I read the S&B paper, it was a relatively arbitrary choice - and
why shouldn't it be? It was only chosen to suppress spurious signals
and expose the slower drift that is inherent in nature. Anyone that
has seen curves of the last 2 million years must recognize that an
averaging of some sort has taken place. It is not often, however,
that the quibble is about the choice of numbers of years, or the
exact methodology - those are chosen simply to expose 'supposedly'
useful data which is otherwise hidden from view.
Let me ask Mike this question. Can he give an example of any dataset
where the S&B characterization of the source author is incorrect? (I
am not vouching for them , merely asking.)
S&B say that they rely on the original characterizations, not that
they are making their own; I don't see a problem a priori on relying
on characterizations of others or, in the present circumstances, of
presenting a literature review. While S&B is a literature review, so
is this section of IPCC TAR, except that the S&B review is more
thorough.
The Mann et al multi-proxy reconstruction of past temperatures has
many problems and these have been well documented by S&B and others.
My reading of the IPCC TAR leads me to the conclusion that Mann et al
has been used as the basis for a number of assertions: 1. Over the
past millennium (at least for the NH) the temperature has not varied
significantly (except for the European/North Atlantic sector) and
hence the climate system has little internal variability. This
statement is supported by an analysis of model behaviour, which also
shows little internal variability in climate models. 2. Recent global
warming, as inferred from instrument records, is large and unusual in
the context of the Mann et al temperature reconstruction from multi-
proxies. 3. Because of the previous limited variability and the
recent warming that cannot be explained by known natural forcing
(volcanic activity and solar insolation changes) human activity is
the likely cause of the recent global change.
In this context, IPCC mounts a powerful case. But the case rests on
two main foundations; the past climate has shown little variability
and the climate models reflect the internal variability of the
climate system. If either or both are shown to be weak or fallacious
then the IPCC case is weakened or fails.
S&B have examined the premise that the globally integrated
temperature has hardly varied over the past millennium prior to the
instrumental record. I agree it is not rocket science that they have
performed. They have looked at the evidence provided by researchers
to see if the trend of the temperature record of the European/North
Atlantic sector (which is not disputed by IPCC) is reflected in
individual records from other parts of the globe (Their three
questions). How objective is their assessment? From a purely
statistical viewpoint the work can be criticised. But if you took a
purely statistical approach you probably would not have sufficient
data to reach an unambiguous conclusion, or you could try statistical
fiddles to combine the data and end up with erroneous results under
the guise of statistical significance. S&B have looked at the data
and reached the conclusion that probably the temperature record from
other parts of the globe follows the same pattern as that of the
European/North Atlantic sector. Of the individual proxy records that
I have seen I would agree that this is the case. I certainly have not
found significant regions of the NH that were cold during the
medieval period and warm during the Little Ice Age period that are
necessary offsets of the European/North Atlantic sector necessary to
reach a hemispherically flat pattern as derived by Mann et al.
S&B have put forward sufficient evidence to challenge the Mann et al
analysis outcome and seriously weaken the IPCC assertions based on
Mann et al. Paleo reconstruction of temperatures and the global
pattern over the past millennium and longer remains a fertile field
for research. It suggests that the climate system is such that a
major temporal variation as is universally recognised for the
European/North Atlantic region would be reflected globally and S&B
have given support to this view.
It is my belief that the S&B work is a sincere endeavour to find out
whether MWP and LIA were worldwide phenomena. The historical evidence
beyond tree ring widths is convincing in my opinion. The concept of
"Little Ice Age" is certainly used practically by all Holocene paleo-
climatologists, who work on oblivious to Mann's "disproof" of its
existence.
Paleoclimatologists tell me that, for debating purposes, they are
more inclined to draw attention to the Holocene Optimum (about 6000
BP) as an undisputed example of climate about 1-2 deg C warmer than
at present, and to ponder the entry and exit from the Younger Dryas
as an example of abrupt climate change, than to get too excited about
the Medieval Warm Period, which seems a very attenuated version.
However, the Little Ice Age seems valid enough as a paleoclimatic
concept. North American geologists repeatedly assert that the 19th
century was the coldest century in North America since the LGM. To
that extent, showing temperature increase since then is not unlike a
mutual fund salesmen showing expected rate of return from a market
bottom - not precisely false, but rather in the realm of sleight-of-
hand.
Regards
Chris

https://web.archive.org/web/20130203114335/http://di2.nu/foia/1057944829.txt

GC Sour lemons or sour grapes? Karl demoted Bates a few years earlier, for a lack of professionalism inter alia. Once Bates realised he could not substantiate the allegations published at Curry's blog, he walked them back pretty smartish. Which part of

no data tampering, no data changing, nothing malicious.

Is giving you the problem?

The 'whistle blower' is John Bates who was not involved in any aspect of the work. NOAA's process is very stove-piped such that beyond seminars there is little dissemination of information across groups. John Bates never participated in any of the numerous technical meetings on the land or marine data I have participated in at NOAA NCEI either in person or remotely.

Peter Thorne (who did work on the project) torpedoes Bates's allegations here: 

http://icarus-maynooth.blogspot.co.uk/2017/02/on-mail-on-sunday-article-on-karl-et-al.html

There may also be something beyond simple “engineers vs. scientists” tension behind Bates’ decision to go public with his allegations. Two former NOAA staffers confirmed to Ars that Tom Karl essentially demoted John Bates in 2012, when Karl was Director of NOAA’s National Centers for Environmental Information. Bates had held the title of Supervisory Meteorologist and Chief of the Remote Sensing Applications Division, but Karl removed him from that position partly due to a failure to maintain professionalism with colleagues, assigning him to a position in which he would no longer supervise other staff. It was apparently no secret that the demotion did not sit well with Bates.

https://arstechnica.com/science/2017/02/article-names-whistleblower-who-told-congress-that-noaa-manipulated-data/

Phil Clarke,

Output from Judith Curry has been consistently more reliable.

Have Peterson, Connolley and Fleck ever admitted their mistakes, or are you standing by William M Connolley on behalf of the Hockey Team?

Which bit of the Hockey Team's variable versions of the Climate should be trusted as honest?

If they could only admit which bits were wrong, it would be easier to preserve those bits that are right.

Could you accept there was a MWP , LIA, and there were concerns about a cold period in the 1970s? Hubert Lamb got 3 out of 3. The Hockey Team, 0 out of 3. No computer models required to work out accuracy.

Nov 23, 2017 at 8:34 AM | Phil Clarke

Are your sources certain that Karl's vesion of events would stand up in Court?

Karl 2015 did not impress, even before Bates responded.

The Karl paper was just one of nearly 70 papers denying the existence of the pause for all sorts of reasons. None has the credibility to gain traction except with those who are desperate to get rid of the pause. The Met Office accepted that there was a pause some time ago.

The pause was interrupted by El Nino. The current cooling of the oceans suggest that the pause may resume.

The current cooling of the oceans suggest that the pause may resume.

https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/

The Met Office accepted that there was a pause some time ago.

Following three record years for global surface mean temperature in 2014-2016, the observed recent slowdown in average global temperature has ended.

The slowdown in the rise of average global temperature had been observed in the recent temperature record, but with the last three record years, this slowdown has ceased.

The Met Office

The met office said in 2013 that the 15 year pause was ending.

The ocean cooling was in the HadCrut data for September.

So it is. Plain as day.

http://woodfortrees.org/plot/hadsst3gl/from:1975/mean:12/plot/hadsst3gl/from:1975/trend

https://tamino.wordpress.com/2017/10/28/how-climate-skeptics-misuse-data-sea-surface-temperature-edition/

Nov 23, 2017 at 3:03 PM | Phil Clarke

I thought Tamino still believed in the Hockey Stick, and the non existence of the LIA and MWP.

Phil Clarke, here is one example of Tamino's use of statistics

https://climateaudit.org/2008/03/26/tamino-and-the-magic-flute/

Tamino and the Magic Flute

"Tamino has recently re-iterated the climate science incantation that Mann’s results have been “verified”. He has done so in the face of the fact that one MBH98 claim after another has been shown to be false. In some cases, the claim has not only been shown to be false, but there is convincing evidence that adverse results were known and not reported.

Today I’m going to look at what constitutes verification of a relationship between proxies and temperature, assessing MBH results in such a context, trying as much as possible to emphasize agreed facts.

Verification 
One thing that Tamino and I agree on is that a proposed reconstruction should “pass verification”. Tamino says:

… frankly, that’s the real test of whether or not a reconstruction may be valid or not. If it passes verification, that’s evidence that the relationship between proxies and temperature is a valid one, and that therefore the reconstruction may well reflect reality. If it fails verification, that’s evidence that the reconstruction does not reflect reality. It has the drawback that the data we set aside for verification we must omit from calibration; with less data, the calibration is less precise. But without verification, we can’t really test whether or not the reconstruction has a good chance of being correct.

and later

… it’s the verification statistics that are the real test of whether or not a reconstruction may be valid. Pass verification: probably valid. Fail verification: probably wrong.

While we strongly disagree on what constitutes “verification” and whether the MBH reconstruction “passes” verification, I’m prepared to stipulate to a verification standard."

What to do when moving end points slightly gives you wildly varying results -aka cherry picking.

Use all start and end points within your area of interest.

E.G. If you want to see a 10 year trend then chose say, 5 values before and 5 values after, at the start of the 10 year period and at the end of the 10 year period.

What do you get? a range of trends, thats as close as you are going to get.

It gets worse.

We talk of hottest years or 30 year trends etc.

The raw data is daily averages (suspect : (Tmax-Tmin)/2) we then change them into an annual average or smooth them in another way.

We only need to smooth or average if we are creating a graph to look at.

Stats routines should always be fed with non smoothed data. Is it I wonder?

Here are five members of the Hockey Team, justifying themselves. The last Comment on the thread produces some interesting responses from the Hockey Team, even quoting a paper by Jones and Mann. CRU knew there was a problem with the MWP.

http://www.realclimate.org/index.php/archives/2005/01/senator-inhofe/#more-97
Senator Inhofe on Climate Change

Filed under: Arctic and Antarctic Climate modelling Climate Science Greenhouse gases Paleoclimate — group @ 10 January 2005

by Michael Mann, Stefan Rahmstorf, Gavin Schmidt, Eric Steig, and William Connolley

"Senator James Inhofe (R) of Oklahoma recently provided us with an update of his views on the issue of climate change in a speech given on the opening senate session, January 4, 2005. His speech opened with the statement:

As I said on the Senate floor on July 28, 2003, “much of the debate over global warming is predicated on fear, rather than science.” I called the threat of catastrophic global warming the “greatest hoax ever perpetrated on the American people,” a statement that, to put it mildly, was not viewed kindly by environmental extremists and their elitist organizations.

Cutting through much of his polemic, Inhofe’s speech contains three lines of scientific argument which, according to him, provide “compelling new scientific evidence” that anthropogenic global warming is not threatening. We here submit his statements to scrutiny."

Read the full post, but the issues are The Paleoclimate Record, Global Sea Level Rise and Recent Arctic Warming.

Clips

The map you linked has about 900 links. I sampled two dozen.

In those papers that reported MWP type warming disagreed on the start time, somewhere between 800AD and 1100AD.
The end time varied between 1150 and 1500.

Some papers described cooling, not warming. others described wetter or dryer conditions.

On the basis of my sample, the evidence for the major MWP golf charlie espouses is so vague and contradictory as to be meaningless.

You may be familiar with the term Gish Gallop. IMHO that map is a Gish Gallop.

Incidentally, do you know the meaning of the word "trick" in mathematics? It is a way of doing a calculation using fewer steps. Most climate change deniers are evidently not mathematical.