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jethro

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I linked to discussions with plenty of very serious criticisms of the M&W paper. Y.S., instead of insulting me for my views, why don't you head over to Deep Climate and see if you can come up with reasons why those criticisms are invalid, ditto for the criticisms at RealClimate. There's no point in having a debate with you here as all you do is throw insults when anybody suggests that MacIntyre might be wrong, Wegman might be a politicised and plagiarised report, or that the latest paper purporting to raise doubts about anthropogenic global warming turns out to have a number of critical flaws. When was the last time you were truly sceptical of claims made by MacIntyre, Spencer or that ilk? I'm sceptical of every scientific claim I see, whatever side of the fence it's from - some of those claims stand up to scrutiny, others don't. And I'll consider a claim rubbish if it is not supported by evidence. M&W's claims about reconstructive ability appears not to be supported by evidence.

http://deepclimate.org/2010/08/19/mcshane-and-wyner-2010/

Though I do think M&W's statement is rather funny, for a skeptic paper:

"Using our model, we calculate that there is a 36% posterior probability that 1998 was the warmest year over the past thousand. If we consider rolling decades, 1997-2006 is the warmest on record; our model gives an 80% chance that it was the warmest in the past thousand years." :)

I just don't think the stats they did look likely to stand up to scrutiny, and their background reading falls very flat.

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I linked to discussions with plenty of very serious criticisms of the M&W paper. Y.S., instead of insulting me for my views, why don't you head over to Deep Climate and see if you can come up with reasons why those criticisms are invalid, ditto for the criticisms at RealClimate. There's no point in having a debate with you here as all you do is throw insults when anybody suggests that MacIntyre might be wrong, Wegman might be a politicised and plagiarised report, or that the latest paper purporting to raise doubts about anthropogenic global warming turns out to have a number of critical flaws. When was the last time you were truly sceptical of claims made by MacIntyre, Spencer or that ilk? I'm sceptical of every scientific claim I see, whatever side of the fence it's from - some of those claims stand up to scrutiny, others don't. And I'll consider a claim rubbish if it is not supported by evidence. M&W's claims about reconstructive ability appears not to be supported by evidence.

http://deepclimate.o...and-wyner-2010/

Though I do think M&W's statement is rather funny, for a skeptic paper:

"Using our model, we calculate that there is a 36% posterior probability that 1998 was the warmest year over the past thousand. If we consider rolling decades, 1997-2006 is the warmest on record; our model gives an 80% chance that it was the warmest in the past thousand years." :p

I just don't think the stats they did look likely to stand up to scrutiny, and their background reading falls very flat.

SSS

Its the overwhelming weight of evidence against the 'Hockey-stick' papers, along with other non-tree ring proxy series that makes the argument.

Not everybody who is critical can be wrong.

Independant panel conclusions also back this up and please stop insulting Wegman. You Cherry pick your arguments. Deep climate or Climate audit whatever.

The Hockey stick is dead, the maths used mined the data and the tree ring proxy series used (which appears in all the Mann Papers) have been highly questioned as being unsuitable. This latest report is just another nail in the coffin.

I have posted previous papers than use non-tree ring proxy data and which have shown no hockey stick. Known history would add weight to a medieval warm period and little ice age (certain for the Northern hemisphere) ..... the only thing that does not stack up is those ridiculous hockey stick papers. Its a joke and always has been.

Yet we are all to believe its okay and all the other folks are not 'proper scientists' or have somehow misunderstood the mighty Mann ..... come off it.

Y.S

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Funny how you keep saying the hockey stick is dead, yet it appears in numerous different proxies and numerous different reconstructions. Far from being dead, it's actually one of the most validated graphs in science. It does not just refer to tree rings (as you seem so obsessed by), but to a multitude of other proxies from flowering dates to borehole temperatures, via glaciers on the way. Quite what is 'cherry picking' about finding mutually consistent evidence from a great diversity of sources, while there is no scientifically valid evidence to suggest otherwise?

http://www.skepticalscience.com/broken-hockey-stick.htm

On Wegman among other things - it is well worth slandering as I would not use it even as toilet paper:

http://www.desmogblog.com/crescendo-climategate-cacophony

http://deepclimate.org/2010/04/22/wegman-and-saids-social-network-sources-more-dubious-scholarship/ [and links within]

As for the NAS report which you persist in suggesating that it wrecked Mann's early hockey stick, maybe you should read the report and the discussion here:

http://www.realclimate.org/index.php/archives/2006/06/national-academies-synthesis-report/

From the NAS summary:

"The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on ice caps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years. Not all individual proxy records indicate that the recent warmth is unprecedented, although a larger fraction of geographically diverse sites experienced exceptional warmth during the late 20th century than during any other extended period from A.D. 900 onward." Hardly demolishing the paper, is it?

http://www.nap.edu/catalog.php?record_id=11676

Climate science moved on, past Mann et al (1998,1999), and confirmed the hockey stick. Only those people like MacIntyre and cronies (Montford, Monckton) still claim it's "broken", failing to realise there are many sticks made of different materials.

The hockey stick is dead... in the eyes of a very few.

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The theory and validity of human induced climate change doesn't hang in the balance based upon one single piece of scientific work - shoddy or excellent.

Yorkshiresnows and sunny starry skies - isn't it about time you two agreed to disagree on this and let it drop? Michael Mann and his work isn't the be-all and end-all of climate change.

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<BR>The theory and validity of human induced climate change doesn't hang in the balance based upon one single piece of scientific work  - shoddy or excellent. <BR><BR>Yorkshiresnows and sunny starry skies - isn't it about time you two agreed to disagree on this and let it drop? Michael Mann and his work isn't the be-all and end-all of climate change.

Hi Jethro,

Yes, I've had enough and I guess evrybody else must have too. Just infuriated by the lack of vision .... or indeed common bleedin sense.

No more from me on this issue.

Let the blind carry on

Y.S

Edited by Yorkshiresnows

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Cheers YS.

There's plenty more in this debate to argue over, who knows, there may even be common ground?

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The theory and validity of human induced climate change doesn't hang in the balance based upon one single piece of scientific work - shoddy or excellent.

Yorkshiresnows and sunny starry skies - isn't it about time you two agreed to disagree on this and let it drop? Michael Mann and his work isn't the be-all and end-all of climate change.

Jethro, those are exactly the two points I've been making all along. Thankyou. I'm happy not to discuss with YS anymore, as the concept of a rational discussion seems to disappear when the words 'hockey stick' appear in relation to research. It's not even that important in connecting humans to climate change - other lines of evidence are far more important (radiation measurements, changing patterns of temperature etc).

Edited by sunny starry skies

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Hi SSS!

I've seen a temperature reconstruction that looks remarkably similar to a 'Swiss Horn'.........

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Jethro, those are exactly the two points I've been making all along. Thankyou. I'm happy not to discuss with YS anymore, as the concept of a rational discussion seems to disappear when the words 'hockey stick' appear in relation to research. It's not even that important in connecting humans to climate change - other lines of evidence are far more important (radiation measurements, changing patterns of temperature etc).

Yes it was .... it provided a clear means to show that past climate was pretty flat until most likely human derived greenhouse gas emissions forced an unprecedented rise in temps. The whole IPCC third summary report centered its arguments around this issue ...... and that graph.

Its not the be all and end all, I agree, but it was made an important issue in selling the whole greenhouse gas derived global warming issue to the general public. But, if there were past periods where similar temperature changes had occureed on a global scale, this then opens the possibility that natural cyclical events / drivers have a role to play.

Surely to god at least that point isn't up for debate ?

Edited by Yorkshiresnows

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IMO the 'hockeystick' has been manipulated (by all sides) by vertical scaling. Then again, what in the graphical representation of statistics hasn't?

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Yes it was .... it provided a clear means to show that past climate was pretty flat until most likely human derived greenhouse gas emissions forced an unprecedented rise in temps. The whole IPCC third summary report centered its arguments around this issue ...... and that graph.

Its not the be all and end all, I agree, but it was made an important issue in selling the whole greenhouse gas derived global warming issue to the general public. But, if there were past periods where similar temperature changes had occureed on a global scale, this then opens the possibility that natural cyclical events / drivers have a role to play.

Surely to god at least that point isn't up for debate ?

Not really, as you then have to show what natural cycle(s) drove such a past change. There is no evidence for natural cycles that can force present climate and past climate in the observed pattern... unless you are arguing that somehow the natural cycles operated in a different way in the past?? [or suggest that half a dozen different proxy types are all wrong in the same direction of wrongness]. You cannot base any hypothesis, or course of action, on an unknown that might be imaginarily the case - you have to show why it is the case. And present a compelling suite of evidence that not only shows your unknown process is consistent with the observed and proxy data, but shows why we can largely disregard CO2 variations which, coincidentally, already explain the observed and proxy data variations. So far, climate skeptics have failed this crucial test.

An while the match between temperature and CO2 over the past 1000 years is quite appealing if the 'swiss horn' is closest to the mark, it does not provide direct evidence for a human imprint on climate. Direct evidence of temperature forcing includes outgoing and downward longwave radiation measurements showing the CO2 signature, and observations of increasing nighttime and winter temperatures, stratospheric cooling etc that show a signature in the forcing pattern of the atmosphere that is neatly consistent with GHGs, but not consistent with other forcings. They, to me, are the most important pieces of evidence. 'Swiss horns' tell us about sensitivity, and indicate a lower sensitivity to forcing than otherwise.

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Not really, as you then have to show what natural cycle(s) drove such a past change. There is no evidence for natural cycles that can force present climate and past climate in the observed pattern... unless you are arguing that somehow the natural cycles operated in a different way in the past?? [or suggest that half a dozen different proxy types are all wrong in the same direction of wrongness]. You cannot base any hypothesis, or course of action, on an unknown that might be imaginarily the case - you have to show why it is the case. And present a compelling suite of evidence that not only shows your unknown process is consistent with the observed and proxy data, but shows why we can largely disregard CO2 variations which, coincidentally, already explain the observed and proxy data variations. So far, climate skeptics have failed this crucial test.

An while the match between temperature and CO2 over the past 1000 years is quite appealing if the 'swiss horn' is closest to the mark, it does not provide direct evidence for a human imprint on climate. Direct evidence of temperature forcing includes outgoing and downward longwave radiation measurements showing the CO2 signature, and observations of increasing nighttime and winter temperatures, stratospheric cooling etc that show a signature in the forcing pattern of the atmosphere that is neatly consistent with GHGs, but not consistent with other forcings. They, to me, are the most important pieces of evidence. 'Swiss horns' tell us about sensitivity, and indicate a lower sensitivity to forcing than otherwise.

I think we agree to disagree.

Y.S

Edited by jethro
No need for the second sentence

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IMO the 'hockeystick' has been manipulated (by all sides) by vertical scaling. Then again, what in the graphical representation of statistics hasn't?

Shhhh.. Careful Pete... You'll make people think that raw data is a good way to do research.. :whistling:http://nwstatic.co.uk/forum/public/style_emoticons/<#EMO_DIR#>/biggrin.gif

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Indeed P.P.!!!

I find the best way to do science is to find a body with massive vested interests ,who want a near 'settled' debate stoking up or skewing and who are willing to pay you lot's of money for doing such.....who needs peer review when you can just make it up and then pay to have it distributed throughout the world by blogs and newspapers?

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who needs peer review when you can just make it up and then pay to have it distributed throughout the world by blogs and newspapers?

That's what's happening isn't it?

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That's what's happening isn't it?

No!!, well who'd have believed it? (the dis-info that is!....)

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A new study published in Nature finds that estimates for ice-mass losses for Greenland and Antarctica have been over-estimated by more than half.

http://icecap.us/index.php/go/joes-blog

"These findings confirm the ongoing shrinkage of the polar ice sheets,†state Bromwich and Nicolas. “However, and most importantly, the newly estimated ice-sheet mass losses represent less than half of other recent GRACE-based estimates for the same time interval: -230 +/- 33 Gt yr-1 for Greenland2 and -132 +/- 26 Gt yr-1 for West Antarctica.†According to Wu et al. “We conclude that a significant revision of the present estimates of glacial isostatic adjustments and land–ocean water exchange is required."

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo938.html

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A new study published in Nature finds that estimates for ice-mass losses for Greenland and Antarctica have been over-estimated by more than half.

http://icecap.us/ind...hp/go/joes-blog

"These findings confirm the ongoing shrinkage of the polar ice sheets,†state Bromwich and Nicolas. “However, and most importantly, the newly estimated ice-sheet mass losses represent less than half of other recent GRACE-based estimates for the same time interval: -230 +/- 33 Gt yr-1 for Greenland2 and -132 +/- 26 Gt yr-1 for West Antarctica.†According to Wu et al. “We conclude that a significant revision of the present estimates of glacial isostatic adjustments and land–ocean water exchange is required."

http://www.nature.co...ll/ngeo938.html

Hi Jethro,

Thanks for posting those links.

Y.S

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Hi J' , from the little i know around the subject I feel this paper is in for a rough ride. We have had plenty of studies into isostatic rejuvenation and even current measures for the acceleration of uplift because of recent mass loss from ice sheets/glaciers.

Let us keep an eye open for the reasons that are brought foreword for having this paper fall or the clamour (from NASA/NSIDC ) to revise their findings and adjust for future research.

Either I'm well out of touch with today's models or we have a good idea of the unloading impacts from the last ice age with our own SE sinking relative to NW Scotland's rises. To think we cannot know the 'mass' of the Greenland continent (depth of 'crust' and makeup) so as not to understand it's gravity anom (with or without the ice) makes me wonder whether I dream most of what I know??? To think we do not include both isostatic uplift from both the unloading of the last ice age and the unloading from the current melt (esp. with the papers outlining the 'uplift' acceleration in Greenland) nor have a proper understanding of the rock types building Greenland (to the point of knowing it's mass as it floats on the mantle) is worrisome in the least!

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A new study published in Nature finds that estimates for ice-mass losses for Greenland and Antarctica have been over-estimated by more than half.

http://icecap.us/index.php/go/joes-blog

"These findings confirm the ongoing shrinkage of the polar ice sheets,†state Bromwich and Nicolas. “However, and most importantly, the newly estimated ice-sheet mass losses represent less than half of other recent GRACE-based estimates for the same time interval: -230 +/- 33 Gt yr-1 for Greenland2 and -132 +/- 26 Gt yr-1 for West Antarctica.†According to Wu et al. “We conclude that a significant revision of the present estimates of glacial isostatic adjustments and land–ocean water exchange is required."

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo938.html

Certainly something worth investigating further, although when you open a link and see, Green Swindle, Fox News, and Sean Hannity, the phrase, slightly bias comes into mind. That’s not to say the report has no merit but it would carry more weight for me if the story and report were not being covered by Fox News (pollution of the airways) and Sean hannity (pollution of humanity).

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I didn't like to mention it w.e. and ,without open access to the full paper we are left taking their 'excerpt' as representative of both the paper and it's conclusions. The abstract does not give a 'flavour' of this?

As I say ,time will tell and there are plenty of qualified folk to look at this paper esp. if the 'denialists' bloggers are holding it up as some kind of 'black eye' for AGW. In some ways the climate gate/spring ice has spurred the AGW community into more co-ordinated action against the 'dinialsphere' (of which some quarters seem content to attack all of science as a 'closed club' of folk twisting facts to suit agendas.....unless it agrees with them and then all science is good and must be believed).

The more open and transparent the science the better......so it will be for this (and other) papers.:)

Edited by Gray-Wolf

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Sometimes you've got to take information where you can get it. Sadly this isn't available for free at the moment (at least not that I can find) but for anyone willing to pay, the abstract is linked to for payment. The abstract does give a clear indication of the findings.

It appears from this that our understanding and measurements were wrong and no, our understanding isn't that clear.This isn't a black eye for AGW nor is it being presented as such, to read that into this study IMO does a dis-service to an investigation making a genuine attempt to progress our knowledge. At no point does the article or the abstract make any such claims.

Clarity on the magnitude of ice loss is imperative to anticipate what changes, if any, we can expect in sea level rise, this paper tries to address this issue.

Personally, I'd see this as positive news, both the refining of our knowledge and the prospect that we've lost less ice than originally thought. It doesn't alter the prospects for loosing more from the fringes if the world continues to warm but it does show promise that sea level rises will be less than anticipated. Given that this is one of the major factors in the future projections of land lost to the oceans, leading to displaced people and loss of land fit for cultivation in a world with a burgeoning population - how can it be anything other than good news?

More information is available here on why these studies have thus far been incomplete and how important they are, together with an indication of the calibre of the scientists involved in this study.

http://dynaqlim.fgi.fi/texts/full_program.pdf

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