Following my previous post there has been discussion in the comments on "which graph to believe". Sadly this becomes ideological, for some. I think the major point is that the HPS '97 graph (the one here) just isn't used anymore by anyone, except the septics who want to see a MWP. The graph has never been explicitly disowned, but the authors of it have published plenty more since then, all only going back 500 years (and AFAIK no-one else before or since has tried to use boreholes back that far), and showing a different timing of the cold bit. Naturally, if you're paranoid, this is because the evil IPCC leaned on them. Frankly, thats black-helicopter stuff of the first order, but its also non-historical because MBH'98 only went back 6 centuries, so didn't show the MWP one way or another. You have to wait for MBH'99 for the 1000 years, which was *after* the borehole folk switched to 500 years.
But if you don't like that, then another problem is the temperature it comes out with for the LGM - about -1.5K cooler than "now" (though see next point...). This isn't nearly cold enough - rather a hint that something is wrong.
Yet another point for those wanting a MWP is that the zero point on the graph doesn't represent "now" - it represents start-of-20th-century (becasue the top 100m of data were not used). Given what we know from the instrumental record, then even if you believe this graph, the MWP wasn't warmer than "now" - indeed it was a bit colder.
[Update: a suggestion from someone who has read the paper more attentively than me: It looks to me as though they have done a single inversion using an estimate of the global mean heat flow as a function of depth, as opposed to doing the inversion at each profile and then averaging as in Huang et al. 2000. Their heat flow is based on 37 profiles at 2000m, but 1001 at 100m, so there is a large change in the region being sampled. My guess is that this approach gives meaningless results -W]
Nature 392, 779-787 (23 April 1998) | doi:10.1038/33859; Received 9 May 1997; Accepted 27 February 1998
MBH98 hockey stick was submitted in the first half of 1997.
MBH99 in GRL was published around March (volume 26/6) and it was surely submitted in 1998.
[Yes yes, and the '98 borehole paper was published instantaneously?
Now - why are you so studiously ignoring the problem with the LGM temperatures in the HPS '97 study? -W]
Come on, you don't really believe that other fellow members of the paleoclimate community didn't know that MBH were going to publish hockey stick before it was actually published in 1998, do you? Or do you think that MBH 1998 was written within days?
It's amazing that you have no idea what's wrong with the 1997 paper - you don't even have some confusing controversial propaganda in this case - yet still you think it is rational that the 1998 paper is used but the 1997 paper is buried.
The reason is that around 1998, the climate science has been hijacked by politicized scientists, parasites, and crackpots who have very different methods to choose data and papers than scientists should have.
The title should have said "More Goring" or "Gore Goring", it would be more accurate.
So, back in 1998, MBH were telling everyone that they had a paper coming up to prove that global warming was happening, and that they had better not say anything against it, or they would get their legs broken?
Is that about how you see it, lubos?
Actually old stoat, you mis-state my position. I don't believe either of them as quantitative data until the method is at least more consistently established.
Hi Lubos. I notice you're conveniently ignoring the LGM temperature problem that yuor favoured version has. Errm, and the bit about the MWP temperatures. Too busy with the black helicopters :-(
Dear guthrie, yes, indeed, what you say is a popular summary of what I think.
Dear William, I am not only ignoring the "LGM temperature problem" but I even deny that this is a problem of their work. It is a problem of consistency between various papers (and especially various parts of the lore and myths) but it doesn't follow that Pollack et al. are those who have the problem.
If the holocene maximum was really much warmer than today, which I think is very plausible given many other sources of data, there is no problem, except a problem with papers that disagree with this likely fact.
Unless you have a 5-sigma guaranteed reliable picture of the history, it is just scientifically wrong to choose some random papers to be dogmas that everyone else must agree with unless they want to have a "problem".
Your biased way of talking about "problems" exactly demonstrates guthrie's point, namely that there exists the atmosphere saying that if someone publishes anything that disagrees with certain now "privileged" papers, his legs will be broken.
This is no science. It's religion with its dogmas and inquisition.
I think that everyone who reads this blog reads mine as well but anyway, I wrote about this topic here:
You won't believe what sunspots do to rabbits ...
But back to boring, I'm seeing a lot more about using cameras to look at the deep ice; and papers like this one
talk about the ice sheets making laminates at the bottom, with rapid changes. Sounds like a recipe for slippery.
Looks like a recipe for slippery
" The clear bottom layer is distinct from the overlying debris-bearing ice and is
located over a 1.6 m tall water- filled cavity. Videos from the bottom
of this borehole show horizontal acceleration of particles sinking into
the cavity, indicating flow of water within the cavity. In the ice-
stream borehole (hereafter IS, Figure 3. 1c, d, 3. 4) a similar layer of
clear ice exists. Here this layer is 10 cm thick and lies over a thin
(mm to cm scale) subglacial water layer. Video sequences from this
borehole show a distinct outflow of borehole water into a mm to cm
scale gap separating the ice from its bed. "
AGU 1998 borehole/climate papers here --- at this point they were talking about millenia-deep records, refining the accuracy, and had already determined that the Medieval warming was in fact Medieval (western European) rather than global, looking at these abstracts. But they apparently did not know that 1998 was an El Nino year when these were published.
Just --- amateurishly --- trying to dig out when people quit looking deeper than 500 years and why.
Hope y'all can invite someone (maybe journal editors?) with, er, deep qualifications in the field to comment on the change you all are describing in what gets published.
I find hints about problems with temperatures being biased by where the ice happened to be as it moved over geothermal heat sources here and there, still wondering if that's a source of error that was discovered and not quantified so led to abandonment of analyses using the raw data from deep holes.
Else the conspiracy is hiding all the temp data. Perhaps the drills broke through into the lands on the inside of the hollow Earth, eh?
Ok, what I see in more recent papers is more specific documentation of ice motion over time, and more mentions about geothermal heat transfer from below.
Motion of 48 kilometers over varying terrain (varying melt rates) over 126.5 Kyears.
How much would that change the temperature of the ice above the melting/sliding layer?
So I speculate -- and this is enough from me as an amateur --- that the deeper temps are not being published due to doubts about deeper temperatures being reliable information about the surface temperature when the snow fell, as compared to being information about thtemperature of the buried surface over which the ice has moved since that time.
"In 2003 bedrock was reached at the NorthGRIP drill site .... The recovered ice core contains an unbroken climate record reaching back to the Eemian warm period [North Greenland Ice Core Project Members, 2004].
In this thesis a new timescale for the ice core is derived ....
The derived timescale assigns an age of
126,500 years to the bottom of the ice at NorthGRIP.
This ice is estimated to have been deposited 48 km upstream from
the drill site. The inversion of the model reveals changing melt rates along the flow line leading to the NorthGRIP drill site. ..."
[Don't forget that most of these boreholes - probably all the ones in the paper - are into rock, not ice -W]
Say what? Which boreholes are in rock?
Honest, I try to read the pages I find, before picking the few I cite (wry grin).
[Errrm, well, you just have to look at the distribution map to see this. Sandstone counts as rock, I suppose. And Clows article says it -W]
The first linked AGU page (from 1998) is mostly about permafrost drilling, although a few mention North Slope sandstone (oil drilling). Several mention ice specifically.
Among those are several mentions of deep time cores; that's why I'm puzzled to read above that nobody's going back more than 500 years nowadays. Did _all_ these studies quit being cited for some reason?
Among those in the first link:
Overpeck's article ("How unprecedented is recent Arctic warming: a look back to the Medieval Warm Period") says:
" A new compilation (this work) of high-resolution paleoclimate records stretching back 1200 years confirms the earlier assertion of Hughes and Diaz (1994; Climatic Change) that the so-called "Medieval Warm Period" (also known as the "Medieval Climate Optimum"), in fact, did not exist in the form of a globally synchronous period as warm, or warmer, than today..... "
Clow's article (Reconstructing Past Climatic Changes in Greenland and Antarctica from Borehole Temperature Measurements) says:
"Although originally conceived to utilize temperature data acquired from
boreholes drilled in rock, the borehole paleothermometry method can be adapted for
use in polar ice sheets. Analysis of borehole temperatures recently acquired by the
USGS system in the Greenland (GISP2 \& GRIP) and East Antarctic (Taylor Dome) ice sheets is improving our understanding of the magnitude of past climatic changes ..."
The second link is entirely papers from the North Greenland Ice core Project -- "bedrock was reached" only after drilling ice. That's where the issues of geothermal heating of the ice as it moves seems to come up, perhaps as a reason to question whether the borehole temp info describes the surface condition when deposited or has gotten warmed up from below.
If all the early ice cores did rely too much on rock coring measurement methods and assumptions --- only belatedly catching on that the ice has moved and been exposed to varying conditions both at base and at surface --- maybe the whole early lot of them are shelved as unreliable? Just wondering. Does seem like a lot of work was done and now isn't being talked about.
[I think you're still missing the point, at least for this paper: that the HPS '97 is rock holes, not ice -W]
I think it's completely obvious that the borehole paper in 1998, inspired by MBH98, started the paradigm of looking into last 500 years - only to the period short enough so that we can only talk about "warming". Beltrami 2002, Mann 2003, and others followed this "convention".
It is equally obvious that with this setup, the borehole method is completely useless. The method would only be interesting if it could see both warming and cooling - some structure in the graphs. The papers where only some trivial monotonic trend in some period is reported from the boreholes are scientifically useless.
" the borehole paper in 1998, inspired by MBH98"
Got any evidence for that, or have you got a time machine?
-and AFAIK no-one else before or since has tried to use boreholes back that far)
Sen---------wait, how boring, covering up for things isn't too important to one who's business it is now covering up for things? Forg
Dear guthrie, as every person with IQ above 80 could have figured out, the punch line of the abstract of the 1998 borehole paper
The geothermal data offer an independent confirmation of the unusual character of 20th-century climate that has emerged from recent multiproxy studies.
That's clearly why they wrote the paper and once again, one must be really stupid not to understand this simple fact.
Ahh, Lubos world again. Instead of suggesting that they did a literature search or saw some of the publicity and thought, "hey, lets compare this to up to date papers and information and see how it gets on", they instead thought "Shit, we'd better agree with him or he'll send the big boys round to break our legs."
Well, look it from the opposite point of view.
Perhaps the deep time studies were about to reveal so much imminent risk of much faster icecap collapse than was then publicly acknowledged as expected -- a decade ago --- that the secret government needed an extra decade to get their secret redoubts in order without risking a runup of real estate prices in desirable areas far from the crowds and nicely placed over unpolluted aquifers --- Paraguay? --- and so threatened to break the budgets of any agency .....
It appears the conspiracy's bolthole was secured by 2005, and publication of deep ice core records resumed. Google Scholar cache here:
Among the articles, this (I suppose this is 'Niels Bohr'ing Boring)
Greenland ice Cores tell Tales on the Eemian Period and Beyond
Dahl-Jensen, D et al.
The deep NGRIP ice core from North Greenland (75N, 42W) is 3090m deep and reaches 125.000 years back in time. The climate record has an extremely high resolution with annual layers of the order of 1 cm right down to the base because basal melt reduces the thinning of the basal layers. The lowest 60 m of the ice core contains ice from the last interglacial period, the Eemian period (OIS-5e) and it is seen from the stable isotopes that the period was 5 deg C warmer in Greenland than our present interglacial period and very stable. The transition to glacial conditions occurred gradually over several thousand years. The NGRIP ice core contains the first undisturbed record of the Eemian period from the North Atlantic region. The NGRIP results contribute with a fix point in the predictions for sea level rise from a globale warming: a 5 deg warming over Greenland corresponds to the global sealevel rise of 5 m ....
And this earlier mention of the ice cores now on their way to the labs:
"High quality Pliocene through Holocene core is anticipated from the McMurdo Ice Shelf site of the upcoming ANDRILL program (to be drilled in late 2006). A key goal of this site will be to recover records of unusually warm interglacial events, allowing integration of proximal and distal evidence of the sensitivity of Antarctica and its ice sheets to climate change."
Perhaps the conspiracy has quit suppressing news from deep climate drilling? I see the usually reliable sources reporting that yes, indeed, the bunkers ("Mariscal Estigarribia, Paraguay") are up and running:
Mar 31, 2007
With links, pictures via Google Maps, and stories from all over South America.
Can't be true, it would've bumped Hilary and Paris off the front pages if it were, eh?
Eli: If you mean wrong about reading both, I am not sure. But I think it's in the same sense as "People who read the Economist may also watch a lot of 'I Love Lucy' reruns."
That's clearly why they wrote the paper and once again, one must be really stupid not to understand this simple fact.
You don't understand facts - you're either aware of them or you aren't. For someone who is going so far out of his way to insult people, you could at least be a bit more intelligent in your mudslinging.
Marion, those two are written for the same age groups, you know, the ones who think Eli is a bunny.
New borehole paper by Huang et al. here:
[Ah now that *is* interesting -W]
[Ah now that *is* interesting -W]
I thought you'd say that.
I've only skimmed it quickly, but it seems to address (at least cursorily) some of the issues you raised last year ... would have liked a bit more about some of them, like the brushoff of LGM in paragraph 20. But the most interesting thing to me was the tone of the paper. Clearly, they're not happy about how the 1997 paper was used in some quarters!
[Oh yes indeed. I'm ever-so-slightly miffed that they don't credit me with getting them to do this work (I did correspond with them about the problem, and the timing is right... Expect a post this evening! -W]