More "hiding the decline"

Steve McIntyre points out some inconvenient data from Law Dome.

==================================

Re-reading Climategate and AR4 Review Comments, I noticed an interesting discussion about handling the Law Dome O18 record – a series used in Mann and Jones (2003) and Jones and Mann (2004) with a very elevated MWP.

The Law Dome O18 series was illustrated in Jones and Mann 2004 as follows (although the digital data for most series in this article was commendably archived, the digital version of the Law Dome O18 series wasn’t. After a couple of years of effort, I obtained it from Tas van Ommen.

AR4 Second Draft Figure 6.11 purported to show the “locations of temperature-sensitive proxy records with data back to 1000, 1500 and 1750″, but, for some reason, didn’t include Law Dome, Quelccaya and other sites. The caption was as follows;

Figure 6.11. Locations of temperature-sensitive proxy records with data back to 1000, 1500 and 1750 (instrumental records: red thermometers; tree-ring: brown triangles; boreholes: black circles; ice-core/ice-boreholes: blue stars; other records including low-resolution records: purple squares). All proxies used in reconstructions [R1] to [R11] of Northern Hemisphere temperatures (see Table 6.1 and Figure 6.10) or used to indicate Southern Hemisphere regional temperatures (Figure 6.12) are included.

Neither was the Law Dome O18 data shown in Figure 6.12, illustrating SH proxy histories.

IPCC AR4 Second Draft Figure 6.12

The IPCC stated of this data:

Taken together, the very sparse evidence for Southern Hemisphere temperatures prior to the period of instrumental records indicates that warming is occurring in some regions. However, more proxy data are required to verify the apparent warm trend.

But of course, that’s not all there is to see.

Steve writes:

Just in case you wondered what Osborn and Overpeck didn’t want you to see, here it is:

Note that the inversion of borehole temperatures raises interesting questions equivalent to principal component retention – see prior posts on this. I’ve asked the Danish institution for the pre-inversion borehole measurements.

Read the complete story here at Climate Audit

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April 6, 2010 1:00 am

I actually just read this post over at CA, and was interested as an antipodean resident who gets told that the MWP wasn’t “global”.
I do find Steve Mc’s posts get very technical and require a lot of patience and persistence to get through. Thanks to those that can summarise this information in more layman’s language.

Adam Soereg
April 6, 2010 1:11 am

In case of any disagreement with the models:
If a proxy record shows a pronounced medieval warming or lack of unprecendentedness there could by only one reason for that. The data is almost certainly wrong and it should be tossed away immediately. Additionally, Mike’s Nature trick can be used as an alternative solution.

April 6, 2010 1:45 am

Anthony,
I read through Steve’s full version of the post to see if I could find it, but other than the inconvenience of the proxy behavior (nothing new to anyone who has read anything about Mann or Briffa ; ) my spider-senses are tingling that maybe an important part of this is that Law Dome is in an area that the Hockey Team has implied did not experience the MWP? A little context/clarification might ne helpful.
Of course… it could also be that maybe I’m the only one who doesn’t know where Law Dome is 😀

D. Patterson
April 6, 2010 2:09 am

NickB. (01:45:14) :
Law Dome is an ice dome and a research station located on the coast of Eastern Antarctica.
http://cdiac.ornl.gov/trends/atm_meth/lawdome_meth.html

Snake Oil Baron
April 6, 2010 2:17 am

“Of course… it could also be that maybe I’m the only one who doesn’t know where Law Dome is :D”

It is just beyond Thunderdome. (Two men enter, one verdict leaves.)

Dave Wendt
April 6, 2010 2:21 am

My initial impression when I first heard of borehole temperature proxies was that I couldn’t believe anyone was actually taking these things seriously. The somewhat broad acceptance that they seem to enjoy led me to wonder if I was missing something and I must admit the math involved in the recons is stuff I haven’t dealt with in about 40 years. The fact that the math is so impenetrable and arbitrary that guys like SM and the Jeffs admit to having difficulty sorting it out, makes me think my first impression was probably correct.

April 6, 2010 3:46 am

Can someone provide the punch line to this controversy at Law Dome? What is the significance of this data? I am left hanging.

West Houston
April 6, 2010 4:37 am

Quoting:
“Can someone provide the punch line to this controversy at Law Dome? What is the significance of this data? I am left hanging.”
Commenting:
It’s in that last graph. A definite Medieval Warm Period warmer than today. In Antarctica. “They” said the MWP was local to Europe – when they admitted to its existence at all, that is.

Frank Lansner
April 6, 2010 4:48 am

Law Dome is not the only Antarctic temperature proxy that CLEARLY shows WARMER MWP than today.
We also have the “Remote Plateau” located at the very South Pole showing warm MWP:
See black graph “37 South Pole”:
http://wattsupwiththat.files.wordpress.com/2009/04/lanser_holocene_figure7.png
Look fig 7 in this article:
http://wattsupwiththat.com/2009/04/11/making-holocene-spaghetti-sauce-by-proxy/
The “Remote Plateau” or “37 South Pole”
is THIS ARTICLE:
Mosley-Thomson 1996 : “Holocene climate changes recorded in an east Antarctica”
Article here:
http://traverse.npolar.no/Resource/articles-of-interest/holocene-climate-changes-recorded-in-an-east-antarctica-ice-core-6-mb
Please have patience to download (!) and then checkout fig 6.
These high quality datapoints for every 2-3 years (ten times better than Vostok..) clearly shows 2 big warming peaks in the medieval that is warmer than today. Ont the very South pole.
These data are O18 – BUT – in the very article, it is written how to translate into temperature, see pages 276-77 i think.
So some of the best data for Antarctica is hard to download, etc. but the message is clear.
(Or take a gooood look at figure 5 here, sum of several proxies of Eastern Antarctica:
http://bprc.osu.edu/Icecore/masson.pdf)

Henry chance
April 6, 2010 5:12 am

When is Algore going to come out and settle this?
He can over rule detrimental proxies.

Bill Marsh
April 6, 2010 5:17 am

And what about the temps the borehole shows for the period 1000BC – 1AD? Seems to me we shouldn’t have been victims back then of the ‘runaway warming’ that we are threatened with if current temps increase more than 2C. Area was significantly warmer 2.5K years ago than today.
This record seems to indicate that the Law Dome area has been in a ‘cold’ pattern of declining temps for the last 2K years or so and is beginning a recovery?
I’m a little puzzled by the apparent ‘divergence’ of the O18 record from the borehole proxy record before about 1000AD or am I just reading too much into it.

John S.
April 6, 2010 5:34 am

Please explain the logic that says on the one hand that we don’t have enough evidence to say we had a global MWP, yet on the other hand Mann bases global proxy temperatures on 3 trees?

April 6, 2010 5:40 am

This is devastating to AGW.
Sir Steve has done it again!

mareeS
April 6, 2010 5:42 am

It’s very cool here tonight, 2 days after Easter Sunday. We’re already in long sleeves. Unusual for the beginning of April.

RexAlan
April 6, 2010 5:46 am

Statement: Goodbye from ilovemycarbondioxide.com by Hans Schreuder.
This is of topic: but:-
http://climaterealists.com/index.php?id=5489&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+ClimaterealistsNewsBlog+%28ClimateRealists+News+Blog%29
I wished him well

Richard Garnache
April 6, 2010 6:12 am

Anthony
OT: I know you are very busy and the task must be daunting. At least it would be for me. I am waiting with bated breath for your I-phone widget. I think you should put a price on it to compensate for the effort. Five dollars would be fine for me.
Dick G.

April 6, 2010 6:29 am

D. Patterson,
Thanks for the reply!
Snake Oil Baron,
Thanks for the laugh! I was going to reply by initials but decided it would probably be better to write out your name. Never noticed that before, I’m sure it’s just a coincidence right? ; )
A MWP signal in Antarctica… I think that could qualify as an inconvenient truth for the Hockey Team
*cue dramatic chipmunk
Dah-dah-duuuuuuummmmm!

D. Patterson
April 6, 2010 6:37 am

John S. (05:34:24) :
Please explain the logic that says on the one hand that we don’t have enough evidence to say we had a global MWP, yet on the other hand Mann bases global proxy temperatures on 3 trees?

Please note, the Law Dome results are based upon three ice cores.

April 6, 2010 6:45 am

Word is starting to percolate up into the consciousness of the general public: click

Milwaukee Bob
April 6, 2010 6:45 am

Heads up and somewhat O/T-
Great article in the WSJ opinion section today –
What’s the Next ‘Global Warming’?
On line it’s behind a subscribe wall so let me summarize:
(Bret Stephens is the writer and he starts with-)
So global warming is dead, nailed into its coffin one devastating disclosure, defection and re-evaluation at a time. Which means that pretty soon we’re going to ‘need another apocalyptic scare to take its place.
(Mr. Stephens then summarizes numerous reports that have appeared here and else ware, then writes-)
Something is going to have to take its place.
The world is now several decades into the era of environmental panic. The subject of the panic changes every few years, but the basic ingredients tend to remain fairly constant.
(1) A trend, a hypothesis, an invention or a discovery disturbs the sense of global equilibrium. Often the agent of distress is undetectable to the senses, like a malign spirit.
(2) A villain – invariably corporate and right-wing – is identified.
(3) Then money begins to flow toward grant-seeking institutions and bureaucracies, which have an interest in raising the level of alarm.
(4) Environmentalists counsel their version of virtue, typically some quasi-totalitarian demands on the pattern of human behavior.
(5) Politicians assemble expert panels and propose sweeping and expensive legislation.
(6) Eventually, the problem vanishes. Few people stop to consider that perhaps it wasn’t such a crisis in the first place,
This is what’s called eschatology-a belief, or psychology, that we are approaching the End Time.
(He then makes a religious analogy and then writes-)
Given the inescapability of weather, it’s no wonder global warming gripped the public mind as long as it did. And there’s always some extreme-weather event happening somewhere to be offered as further evidence of impending catastrophe. But even weather gets boring, and so do the people who natter about it incessantly. What this decade requires is a new and better panic.
Herewith I propose a contest to invent the next panic.
It must involve something ubiquitous, invisible to the naked eye, and preferably mass-produced. And the solution must require taxes, regulation, and other changes to civilization as we know it. The winner gets a beer and a burger, on me, at the 47th street Pig N’ Whistle in New York City. (Nachos for vegetarians.) Happy panicking!
By Bret Stephens
WSJ
Write to bstephens@wsj.com
Who better than us here to come up with a winner?
(Numbering in the above was by me)
Bob Hornbeck
It’s the water, stupid!

April 6, 2010 6:49 am

John S. (05:34:24) :
Please explain the logic that says on the one hand that we don’t have enough evidence to say we had a global MWP, yet on the other hand Mann bases global proxy temperatures on 3 trees?

John S., you are obviously not seeing the wider picture and, eeh, necessity to act now.
PS. I take CET record over any NH proxy any day.

Chris G
April 6, 2010 7:49 am

Let’s see. There are lots of proxy data sets, and some show more or less MWP than others at different times and places. Therefore, there was a global MWP and that proves that CO2 is not a greenhouse gas and/or humans aren’t dumping gigatons of it every year into the atmosphere. Sorry, can someone explain the middle part a bit more clearly?

April 6, 2010 8:01 am

Smokey (06:45:16) :
As long as there are financial institutions, banks, NGO´s pouring money, the Club of Rome elite financing the promotion and marketing of this scam of Climate Change (Aka: “Global Warming”), these contributions, serious studies, real science papers, intelligent books, are but a few drops in a desert. Their objective “buyers”, their “market niché” is the majority of uninformed people, even they resort to innocent childrens´indoctrination: All over the world (the WHOLE world, not only the USA), everyday in almost every classroom, children are taught abot “climate change”, are taught how to “reccycle” to avoid the inminent armageddon. How do you call this?, what measures, if any, are to be taken to stop this insanity?.

April 6, 2010 8:23 am

Milwaukee Bob (06:45:28) :
Got one idea for you: COPY AND PASTE
“All earthquakes, all tsunamis, beginning with the december 2004 Sumatra earthquake and tsunami, all natural disasters now happening, are caused as a reaction, and as a revenge, a retaliation of our wise Mother Nature against those idiotic ideas promoted by Al Gore and other people who have been believing and passing the word about the unexisting phenomenon called by them “Climate Change”. As it has been shown, all measures invented by them and taken against our Mother Nature as the diabolic idea of reducing CO2, the transparent gas we all exhale and green plants breath, in order to produce the oxygen we breath and which makes possible life itself, has profoundly affected the health of our beloved mother earth, so we must reject all those stupid ideas and pass the word about the dangerous consequences we are now facing because of them.

Douglas DC
April 6, 2010 8:27 am

Milwaukee Bob (06:45:28) :
I vote for a cometary or meteor impact possibility. This as two benefits:
One, they might actually use taxes for something useful-like really saving the
Planet.
Two it would get NASA back into the Space Program and not Navel Gazing…
OK, three things. The Warmists could blame the impending strike on our inflated warm atmosphere dragging the errant rock into the Planet….
Grants all around!..

Bruce Cobb
April 6, 2010 8:33 am

Hope they do a lot of time.
Maybe they can do their perp walks alongside the eco-loons threatening “civil disobedience” and informing us “we know where you live”.

Bill Marsh
April 6, 2010 8:35 am

@ Chris G (07:49:33) :
Let’s see. There are lots of proxy data sets, and some show more or less MWP than others at different times and places. Therefore, there was a global MWP and that proves that CO2 is not a greenhouse gas and/or humans aren’t dumping gigatons of it every year into the atmosphere. Sorry, can someone explain the middle part a bit more clearly?
—————————–
Sorry, in reading the post I didn’t see any statements that would lead someone to think that the authors point was “there was a global MWP and that proves that CO2 is not a greenhouse gas and/or humans aren’t dumping gigatons of it every year into the atmosphere.”
I think the point was that there was a Global MWP (and Roman warming, and ‘unnamed pre-Roman warming).
I don’t think that the author believes that CO2 is not a greenhouse gas or that humans aren’t putting gigatons of CO2 into the atmosphere every year. What point were you trying to make?
How did you arrive at this conclusion?

kwik
April 6, 2010 8:43 am

Steve,
I cannot see the punchline either. I see the last graph.
I see a black sawtooth called del CL18. Dont know what that is.
Then I see a red line called Borehole (deg C) uncorrelated to the saw-tooth curve.
It goes from -19.5 deg ….is it 1000 BC? down to -22 deg 1000 AD? ( Does -1000 mean 1000BC ? )
Is this the warming ? At 1000 BC ? 2.5 degrees warmer than…. -22?
Sorry for being so stupid.

Beth Cooper
April 6, 2010 9:03 am

Caves at Waitorno on North Island of New Zealand also show proxy warming greater than present period during MWP, not by three ‘hocky stick’ trees, but by four stalagmites, (Williams, King, Zhao, Collerson, 2004) which supports Ice Dome data.

Beth Cooper
April 6, 2010 9:08 am

Correction,’Law’ Dome. Definitely not an igloo!

Richard A.
April 6, 2010 9:08 am

Milwaukee Bob,
The next scare is easy, and a perfect fit: someone needs to do the dihydrogen oxide thing en masse.

April 6, 2010 9:12 am

Bruce Cobb (08:33:56) :
“we know where you live”.

As Mother Nature perfectly knows where HE lives.
I am sure the last Baja California’s earthquake was just a jogging practice for the BIG ONE, next summer, when Al Baby (Aka:”El Gordo”) moves to his beach residence and marina, so to enjoy him with a nice at least 300 feet high tsunami wave.(tell him to get a big, big , and wide-of course-surfboard).☺

Bill Illis
April 6, 2010 9:45 am

The dO18 ice core data is the best temperature proxy we have.
The fact that the IPCC paleoclimate chapter authors found another clever trick to exclude it just because it shows a MWP, tells you all you need to know about these individuals and the IPCC process in general.

Chris
April 6, 2010 9:48 am

Adam Soereg,
You’ve earned a degree in climate science. Well done sir!

Milwaukee Bob
April 6, 2010 9:49 am

Enneagram (08:23:05) :
So who would we identify as the villain – Mother Nature? or Al Gore and company? 🙂
Douglas DC (08:27:18) :
Good point as I think we all know that mile wide rock from space would sure put a dent in our existence, but as above who’s (what) the villain?
I think, as point out by Bret, we need a NEW “environmental” issue, trend, hypothesis, invention or discovery that “disturbs the sense of global equilibrium.”
I’m thinking – BLACK SOOT…. !! If we just had a study that showed IT is killing children in Zimbabwe…. Talk about grant money!!!

nc
April 6, 2010 9:53 am

I have two bids for the burger and beer.
1. Methane will become the dominate gas in the atmosphere from those four hoofed burger producers.
2. Land is becoming top heavy and is in danger of capsizing from human population. Everyone grab their pool rings, rubber duckies, etc. and tie them to the nearest ocean shoreline. Also donate to Gore’s rubber factory. I am sorry for the last, not.

Milwaukee Bob
April 6, 2010 9:59 am

Richard A., I love it – DHMO! That the kind of thinking we need – to win.
Dihydrogen monoxide:
Is called “hydroxyl acid”, the substance is the major component of acid rain.
Contributes to the “greenhouse effect”.
May cause severe burns.
Is fatal if inhaled.
Contributes to the erosion of our natural landscape.
Accelerates corrosion and rusting of many metals.
May cause electrical failures and decreased effectiveness of automobile brakes. (Toyota should have blamed it!)
Has been found in excised tumors of terminal cancer patients.
Not “new” but with the right – – trickout numbers in a study…. email Bert at WSJ, he might like it.

Bill Marsh
April 6, 2010 10:02 am

kwik (08:43:29) :
Steve,
I cannot see the punchline either. I see the last graph.
I see a black sawtooth called del CL18. Dont know what that is.
Then I see a red line called Borehole (deg C) uncorrelated to the saw-tooth curve.
It goes from -19.5 deg ….is it 1000 BC? down to -22 deg 1000 AD? ( Does -1000 mean 1000BC ? )
Is this the warming ? At 1000 BC ? 2.5 degrees warmer than…. -22?
Sorry for being so stupid.
———
Kwik,
Not stupid.
I think that black line is for the presence of an isotope of Oxygen – O18, it wasn’t CL18, it isn’t easy to read, you would have to know that the ratio of O18/O16 is used as a proxy to determine precipitation temperature to easily recognize it. I somehow managed to pick up and retain that factoid in my other readings of this site (Thx Anthony).
Since this place is in Antarctica the temps are going to be below 0C (hopefully).

toyotawhizguy
April 6, 2010 11:13 am

CRU climate fraudsters “vindicated” by UK Parliament
“The trick was not a ‘neat’ way of handling data, nor a recognized form of statistical analysis. The trick was a clever way of tricking the readers of the IPCC 2001 graphic into receiving a false rhetorical impression” of the coherency of the climate data.”
Link: http://tickerforum.org/cgi-ticker/akcs-www?post=133072

April 6, 2010 11:29 am

Milwaukee Bob (09:59:39) :A very good idea. You have already convinced several thousands of progressive scientists, which in turn will inmediately pass the word to politicians who will wiseacre about it. Good job!
BTW. Fox journalist Tossel recentely made a poll among newyorkers about this issue and about 83% agreed to ban it!
Quite a pity, cause I like to drink that hydroxyl acid with whiskey on frozen pieces of dihydrogen monoxide!

April 6, 2010 11:34 am

This example of how the NSIDC sea ice extent chart was “adjusted” to avoid an inconvenient outcome has been sitting on my desktop for almost a week. This seems to be a good time to use it. The red line is the adjustment: click

Anders L.
April 6, 2010 11:55 am

I think the whole MWP debate is totally useless. Suppose that the world was indeed warmer a thousand years ago due to some natural variation. Does that in any way mean that CO2 is not warming the planet today? Suppose we get another “MWP” in the future, on top of AGW…
In my opinion, the case is closed: if you increase the greenhouse gases in the atmosphere, then the planet will get warmer, no matter how the natural variations come and go. There is just no way around it.

Frank Lansner
April 6, 2010 11:58 am

“Bill Illis (09:45:20) :
The dO18 ice core data is the best temperature proxy we have.
The fact that the IPCC paleoclimate chapter authors found another clever trick to exclude it just because it shows a MWP, tells you all you need to know about these individuals and the IPCC process in general.”
Hi Bill !
I would like to make a study of O18 analysis only. But to do this, i would need
1) Good argument that O18 is state of the art, the best indicator
2) Good methods to translate into temperature.
Can anyone help with this?
K.R. Frank Lansner

L
April 6, 2010 12:00 pm

Chris G: Let’s make this as simple as possible. If there was a MWP, and it was not confined to the North Atlantic where we have written evidence of its reality, then the present warming is not unprecedented and CO2 is not implicated one way or another. Simple enough to bury AGW forever, is it not?

April 6, 2010 12:24 pm

Anders L. (11:55:08),
Even after a one-third increase in CO2, there is no empirical evidence that CO2 has caused any rise in temperature. I tend to think it has a slight effect, but that the minor radiative effect is wildly overstated for political and monetary reasons.
To state that “There is just no way around it” shows that you have your mind made up, and the lack of real world evidence won’t change it. That approach is not scientific, it is emotional.
Keep in mind that the recent rise in temperature might well be only a spurious correlation with the rise in CO2.
It is simply too soon to tell, absent any measurable, testable evidence showing that CO2 is the primary cause — or the cause of any measurable warming at all, for that matter.
At this point AGW is only an unverified hypothesis, and the proper course of action is to be skeptical until there is actual evidence that CO2 is causing global warming.

Chris G
April 6, 2010 12:34 pm

L,
No, it is not. You have voiced the fallacy that there is only one driver of climate. _No one_ claims that anthropogenic CO2 is the only driver of climate; so, the fact that there have been climate changes in the past in no way refutes that CO2 is the dominate driver the changes we are seeing in the past century.
So, what is your stance?
That CO2 is not a GHG? If so, please go open a physics textbook, and try to read it.
That more GHGs do not lead to more warming? Please see the definition of a GHG, and again, open a physics textbook.
If neither of these fit your stance, then how much warming do you predict from a doubling of CO2? And how do you arrive at that figure?

Readertom
April 6, 2010 1:19 pm

I appreciate the questions asked in these comments. Most of them are things I didn’t know the answer to, but didn’t want to be thought ignorant. If we were really concerned about co2, why don’t we have a mass planting of trees to absorb it? Oh, I know, there wouldn’t be a lot of grant money.

April 6, 2010 1:56 pm

I took brief look at some of the FIO emails and files. There is a lot of material there that needs thorough investigations, as you all know. Anyway, one email that caught me eye was ‘briffa-keigwin.email.txt’. I’ve plotted out the data and present it here:
http://www.trevoole.co.uk/Questioning_Climate/userfiles/gallery/In_Progress_Graphics/d18O_data_from_Briffa-Keigwin_email_of_FOI2009zip.htm
If ice volume, of which d18O is supposed to be a proxy, scales with temperature then where is the hockey-stick? Generally d18O is in good agreement with dD temperature in ice cores.
I don’t know if this time-series has been published as it is here or just used as part of a multii-proxy reconstruction. It might be interesting to find out. However I note:
Quote: “The final figure of the published data (1996) attenuated the signal by lumping the data into 50yr boxes …”

Chris G
April 6, 2010 1:57 pm

Bill Marsh,
Well, what is the point of the article?
I interpreted it as either a discussion of the science, whether the MWP was global or not, or as an attempt at character assassination. I took the science route. And, since the agenda of this site is to refute AGW theory, I put it in that context. But, it really doesn’t fit in that context, which is my point.

rbateman
April 6, 2010 2:45 pm

Smokey (12:24:59) :
The way I am seeing this is that
1.) the MWP was much warmer than today’s warming period
2.) Greenhouse gases may contribute to warming
3.) the contribution that is implied to warming is NOT sufficient to raise global temps to the MWP levels, so there really isn’t anything to get excited about, nor is there anything to be gained in limiting them.
4.) the stupidest thing that can happen is to be messing with C02 concentrations necessary for the biological cycles when an impending cooling cycle is taking place.

DirkH
April 6, 2010 3:17 pm

“Chris G (12:34:58) :
[…]
That CO2 is not a GHG? If so, please go open a physics textbook, and try to read it.
That more GHGs do not lead to more warming? Please see the definition of a GHG, and again, open a physics textbook.”
Do CO2 and H2O not compete for the same frequencies? Is the CO2 GH effect not nearly saturated even without taking this competition into consideration? Your strategy of showing it as simple and proven don’t work here.

April 6, 2010 3:47 pm

Chris G (12:34:58) :
You have no physical basis for your non sequitur:
“… the fact that there have been climate changes in the past in no way refutes that CO2 is the dominate driver the changes we are seeing in the past century.”
There is zero empirical [real world], testable evidence that CO2 is a significant forcing of temperature. None. There is radiative physics, which is fine as far as it goes. But we really know too little about the climate to state that “CO2 is the dominate [sic] driver [of] the changes we are seeing in the past century.” That is an evidence-free claim.
Any effect from CO2 depends on how sensitive the climate is to additional CO2 – the climate sensitivity number – and also on CO2’s persistence in the atmosphere. Keep in mind too that human additions to natural CO2 emissions are only about one molecule in 34. Almost all CO2 emitted from all sources is due to natural emissions.
The planet has warmed around 0.7° C in more than a century, while CO2 has risen by about one-third. But did the rise in CO2 cause that rise in temperature? Or are there other factors at work, such as natural warming from the Little Ice Age? Or was the CO2/temperature correlation completely specious? In other words, did the planet happen to warm naturally at the same time, coincidentally and independent of CO2? There is evidence for that.
The fact that on all time scales, changes in CO2 follow changes in temperature is a mighty big clue. People who say “This time it’s different” are invariably proven wrong, whether they’re predicting it will never rain again because they’re in a long drought, or predicting a permanent new plateau in the stock market.
CO2 has the same effect on the climate whether it’s now, or a thousand years ago, or ten million years ago. The laws of physics don’t change.
The climate has gone into major Ice Ages when CO2 has been many times higher than it is today. In fact, the only correlation between CO2 and temperature is that CO2 follows temperature. It has never been proven to be the cause of temperature changes. Since cause cannot follow effect, why – exactly – would radiative physics act differently now? Why would CO2 suddenly become the cause? Please answer using verifiable evidence.
You ask: “how much warming do you predict from a doubling of CO2? And how do you arrive at that figure?”
A generous answer is: a little over 1.6° per doubling from pre-industrial levels; about 280 ppmv. So we’re looking at a maximum of about 0.8° to go: click
But based on the ever declining estimates of climate sensitivity, that number is probably too high. And even if it’s correct, there is no problem with an additional 0.8° temperature rise; the beneficial effects far outweigh any negatives.
Finally, you say that “the agenda of this site is to refute AGW theory [sic].” That is wrong.
The purpose of this site is to find correct answers. Since all honest scientists are skeptics first and foremost, we do not accept scary proclamations based on always-inaccurate GCMs, none of which can make accurate predictions. Nor do we accept peer reviewed opinions that fail to provide the raw data and methods they are purportedly based on.
The climate peer review system has lost its credibility. It has been corrupted by money, by status, by constant expense paid trips around the world, and by its allegiance to the political appointees in the IPCC, rather than to the taxpaying public that pays their basic salaries. Skeptical scientists soon find that if they want to be invited to holiday conferences, or have their papers published, they had better keep their skepticism to themselves.
The author of this article, Steve McIntyre, was never the beneficiary of the loot flowing to the climate alarmist contingent, so he has no reason to invent alarming hypotheses. He is the primary reason that the Mann hockey stick chart was debunked. You can learn more honest science here than from all the IPCC political appointees put together. And it’s all free.

GaryPearse
April 6, 2010 5:40 pm

D. Patterson
“…they only used 3 ice cores”
How devious! Do you realize that each few mm core is a sample? If you have several 100s of samples in a sequence that gives a MWP pattern that is repeated in other holes is good sampling. Choosing 3 trees and rejecting a hundred others that were available is malpractice. Gee they only use one thermometer at a town -is this enough to show global warming for a hundred years? Worse, if you are happy with carefully choosing 3 trees to create the hockey stick, which even the creators have now rejected, why would your masters hide the three cores evidence if they were seeking truth? With what has transpired since NOv 09, I have to wonder how hard it was to convince you of agw in the first place – clearly its a political thing with you.

vigilantfish
April 6, 2010 7:51 pm

Steve,
I went to the entire thread on your website that was linked here, and want to express my appreciation for what you are doing. So many of the ‘CRUtape letters’ are meaningless without the back story, and here you are, providing the context that is missing in a series of e-mails that reveals yet another series of scandalous treatments of science by Jones et al in their quest to get only the desired answer. Keep up the great work! There will have to be a Vol. 2 of The CRUtape Letters!

Ed
April 7, 2010 9:04 am

“If there was a MWP, and it was not confined to the North Atlantic where we have written evidence of its reality, then the present warming is not unprecedented and CO2 is not implicated one way or another. Simple enough to bury AGW forever, is it not?”
You’re not even wrong, because you make an elementary logical fallacy.
Here’s an analogy:
We have an arson suspect for whom we have some material evidence that he started a bushfire. We also know that lightning has started bushfires since long before humans existed.
Does the latter fact disprove the charge that the suspect commited arson? If you believe so, then you’re making exactly the same logical fallacy.
This is the problem with the climate change “debate”, that it is so riddled with logical fallacies and other elements of pseudoscience.

April 7, 2010 10:53 am

Ed (09:04:37),
Just put a period after “unprecedented” in the first sentence, and we’re good to go.

Ed
April 7, 2010 11:30 am

I don’t understand your point Smokey. If you split that sentence up then it changes the meaning completely and no longer says that the a worldwide MWP disproves AGW in my opinion. The existance of a worldwide MWP is logically decoupled from the existance of AGW and it just becomes a collection of unlinked assertions.

April 7, 2010 5:04 pm

Ed (11:30:50),
I was being facetious. Sorry, I should have put “/sarc” under my response. If I had been arguing seriously, my explanation would have been more than a sentence.
When I went to school there was never any question about the MWP. The physical evidence showing that it occurred and was warmer than now is found throughout the world, in both hemispheres.
Because a warmer MWP debunks the idea that human emitted carbon dioxide has anything but an insignificant effect on the temperature [if that], those who stood to gain from the CO2 scare needed to show that we are currently undergoing unprecedented warming. Since we’re not, they had to do something about the MWP problem.
Dr. David Deming of the University of Oklahoma testified to a Senate subcommittee in 2006 that he received an email from a colleague [who thought Deming was with the alarmist crowd], stating, “We have to get rid of the Medieval Warm Period.” [source]
And of course Michael Mann was debunked by Steve McIntyre after Mann attempted to show that the MWP was cooler than now: click
The fabrication that the MWP was only regional is a desperate attempt to prop up the increasingly ridiculous catastrophic AGW hypothesis. The MWP lasted for 400 years. There were short-lived cooler periods during those four centuries, but overall the MWP was significantly warmer than today: click
There is no credible evidence that the MWP was confined to one location on the globe, at one general latitude. That would pretty much violate the 2nd Law of Thermodynamics, since winds and ocean currents would tend to even out global temperatures over four hundred years.
I was being sarcastic because only the most credulous true believers in the evil of “carbon” [by which the ignorant mean CO2] still argue that the MWP was a local “anomaly.” With a warmer MWP, the whole CAGW hypothesis is unsupportable.

Roger Knights
April 8, 2010 6:47 am

Anders L. (11:55:08) :
I think the whole MWP debate is totally useless. Suppose that the world was indeed warmer a thousand years ago due to some natural variation. Does that in any way mean that CO2 is not warming the planet today? Suppose we get another “MWP” in the future, on top of AGW…

The existence of a long-term, global, significantly warmer MWP implies that “We’ve been here before” in terms of temperature and that:
1. No runaway warming effects occurred. E.g., from decreased albedo and methane-released-from-permafrost. (Apparently shrubs start growing in the tundra to shade the permafrost — a negative feedback that was recently discovered.) The sea level didn’t rise alarmingly.
2. The Present Warm Period (PWP) is well within the range of recent-historic natural variation, making it less likely that CO2 is the major cause of it, and reducing the credibility and/or strength of the greenhouse gas argument.
3. The warmist establishment, including the IPCC, that tried to erase the MWP and created the hockey stick, has been “crying wolf.” I.e., the alarmists are “globally” untrustworthy. This is the most important implication of this controversy.

In my opinion, the case is closed: if you increase the greenhouse gases in the atmosphere, then the planet will get warmer, no matter how the natural variations come and go. There is just no way around it.

Sure, but how much will it rise? If there are no large positive feedback effects, it’s not worth worrying about.
Are there any realistic alternatives to coal and oil (aside from new-tech nuclear)? Surely there are some “no regrets” policies we could all agree on, like encouragement for better insulation and for the use of natural gas for heating. But major penalization of carbon would be economically devastating.
If “we” (the developed world) do reduce our emissions, will developing countries like China curtail theirs significantly? (Very unlikely IMO.) If not, why bother?
If “we” (the entire world) do reduce our emissions, will that have a noticeable effect on atmospheric CO2? (Very unlikely according to Monckton.) If not, why bother?
Has the effort by the EU to penalize emissions and encourage the development of renewable energy sources lived up to the hype of its promoters, or has it mostly fallen flat? If the latter, why follow in its footsteps?
Have the alarmists established their credibility as trustworthy guides — or mostly as faddish, sophistical, and partisan alarmists? If the latter, their credibility is that of other advocacy groups and causes — low.
I don’t want to go into all the details of these points. There’s an immense amount of justification for a “keep cool” position on this site in the archived threads. (I only wish that the 10% best articles and comments were flagged or highlighted to make skimming by new visitors easier.)

Ed
April 8, 2010 8:37 am

You still don’t present any logical case for a worldwide MWP disproving AGW. These past temperature reconstructions have fervently gripped the popular imagination, but they do not in themselves prove much in regards to AGW. Instead, it is detailed analysis of 20th Century data, not pre-instrumental data, that provides evidence for AGW. Simply put there is evidence for warming that cannot be explained through natural phenomena in the 20th Century-present, eg historically warm temperatures at a time when natural variables such as the output of the sun are historically “cool”.
Let us imagine that all these studies were wrong and that the MWP was worldwide and significantly warmer than today. That would simply prove that natural causes can cause warming greater than we have seen in recent decades. Yet this is already known, and not controversial; we have evidence that the last interglacial was significantly warmer than today and that sea-levels were 6-8m higher than now. We know the Paleocene-Eocene Thermal Maximum of 55 million years ago was dramatically warmer than today, with sub-tropical forests growing well within the Arctic Circle.
I am intrigued by your assertion that regional climate change violates the Second Law of Thermodynamics. Have you got any reliable sources for that? Even as a non-physicist it strikes me as unlikely. Here’s why. Climates are not distributed in neat latitude bands around the world, but are strongly influenced by ocean circulation etc. North West Europe is much warmer than other locations at a similar latitude because of the North Atlantic Drift. Drift Ice in the Sea of Okhotsk reachest the same latitude as the mild Adriatic Sea. Would it violate the 2nd Law of Thermodynamics for a weakening and strengthening North Atlantic Drift to cause a cooling and warming of Europe, for example? I think not.
Steve McIntyre is the only significant paper from a reliable source to make these findings, as far as I am aware, and what is more was published in a journal of social science, which surely makes it far less compelling than those that came to a different conclusion published in respected natural science journals. Further, his paper was rejected by Nature (probably the most prestigious scientific publication in the world) as faulty and has been criticised as having a faulty method by Rutherford et al in Journal of Climate. Since then his findings have not been published in scientific publications, only in opinion pieces and other non-peer-reviewed publications.
Thus to rely on this particular source is troublesome; one of the distinguishing characteristics of pseudoscience is to rely heavily or almost exclusively on one study’s findings while ignoring a much larger number of studies that are contradictory. Mann’s findings, which McIntyre attacked, were not unique, but similar to findings by multiple independent teams.
Speaking of reliable sources, what reliable sources (ie peer reviewed scientific journal sources) do you have for the sweeping statement “with a warmer MWP, the whole CAGW hypothesis is unsupportable”? It seems as though you dismiss Nature and other highly regarded scientific publications as “credulous true believers in the evil of ‘carbon'”, in favour of, it would seem, non-scientific internet opinion pieces. This leaves your argument with little weight.