gmoran
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Posts posted by gmoran
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I accept Mann's (and Rutherford's, and Moberg's, and Hegerl's) reconstruction as it is presented, with known uncertainties and error bars;
Interesting because I accept it as a valid piece of research as well. I think the picture the graph paints is dead wrong (opinion), but the research and methodology have to be taken at face value.
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The MWP/LIA issue is not about whether or not there is real natural climate variability; this is self-evidently the case. It is about whether current values, and projected future ones, are exceptional. None of the papers I cite above claims that the MWP or LIA didn't happen, only that the temperature reconstructions, revised with new data, suggest that the current temperature is very likely as high or higher than temps in the MWP (with a sizeable error bar on the historic data). The importance of this is to place into context the current warming phase, and to provide a guide as to future uncertainties, based on the best possible information available about past climates.
Given that I could pretty well sign up to this statement, we are probably not too far apart.
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Go on...
example, please:
:)P
Hans von Storch, Stephen McIntyre and Ross McKitrick, Edward Wegman.
The National Research Council's "Temperature Reconstructions for 2000 Years" report sort of backed Mann, saying there were statistical errors but that they were not significant, but also said beyond 400 years there was less confidence. They also reaffirmed the widespread support for LIA and MWP from a variety of evidential sources.
Mann himself in an article to Nature in 2006 explained that in the original paper it was stated there was a need for more widespread high resolution data, and the uncertainties were a major point of the paper.
But this all misses the point. Manns paper represented a major shift in the accepted view, which itself was support by a wealth of good and diverse evidence. So the onus is on Mann and his supporters to prove his version of events is the correct one. This patently hasn't happened yet (even though the graphic itself has become iconic and is now widely used as fact).
If you accept Manns reconstruction of past temperatures, fine, but you shouldn't be expecting everyone else to accept it as bald fact, it simply isn't there yet.
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Ok, another of the things about AGW proponents that somewhat annoys me, it could be best summed up using this Robert Vaughan line from Superman 3: "A great man once said, I think it was Ghengis Khan, it is not enough that I should succeed, everyone else must fail".
The HS does not 'get rid of' the MWP/LIA it finds they are real but muted - subsequent studies have backed these findings up. There is debate about borehole recons.And other studies both before and since Mann support the established view that the MWP and LIA were both significant and global; it also of course makes perfect sense that there was real variability in our climate before. And it doesn't weaken the arguments for the current AGW enhanced warming. So why must everything that weakens the presentation of AGW to the masses be attacked?
Well a bit of a debate about borehole techniques, which sort of fizzles out.
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This is a mischaracterisation both of the fact and of my comment on the 'hockey stick'; no claim is being made to it's being a 'holy grail'. It's methodology and the conclusions of the paper it originally appeared in (MBH '98) have been tested to destruction and not found wanting. Therefore, it is fair to criticise those who claim some problem with it, unless they can point to a fault in the paper which the National Academy of Science somehow missed. I am aware of the critiques on 'climate audit', but McIntyre is pretty much a lone voice in insisting that MBH is fatally flawed. A close study of M&M's critique of MBH concluded that it did not establish that there was any significant error in the MBH graph.
This isn't correct. There have been a number of papers that have been critical of Mann.
However there seem to me to be problems that stick out like a sore thumb. The hockey stick graph grafts thermometer readings onto proxy readings. Secondly the HS gets rid of the medieval warming and the diminish the little ice age. The evidence for both of these events is very strong, and have excellent providence, being backed up by borehole readings (far more accurate) and documentation of the time. The MWP and LIA are real.
Decades of research has supported a view of the climate of the last 1000 years that has an expected variability. Manns paper didn't change or invalidate the accepted science.
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Okay, how can I convince you that I am not necessarily a part of the Green movement?
If you accept that agreeing that AGW is real does not need to imply an 'environmentalist' response, would you be willing to agree that AGW is an actual, real phenomenon?
:)P
It is evident you are interested primarily in the science, I was just explaining why the pro AGW stance can be irritating, and I think it really does come from the attitude of the greens; but that this language tends to leach into wider AGW sentiments.
And I already agree AGW is "real", in as much that I believe that a significant amount of the current warming is due to industrial CO2. To me the main uncertainty is the projected future effects, and in that area I tend to the conservative.
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How do you think we can improve the presentation of the information so as to make it easier to understand? What would give our arguments more credibility? If you can help with these questions, I am sure that some of us will try to help you understand the technical issues.
The problem with the style of AGW is the Green movement. GW is presented as being humanities fault, that we are destroying the planet, and that the only solution is to drastically cut carbon emissions.
Like all systems, the earths temperature modulates around a stable equlibrium. We are currently on an upward trend. The rise due to CO2 is on top of this. So GW in general is not humanities fault, however we are increasing the proportion of atmospheric CO2 and this is and will continue to have a warming effect.
Anthropogenic CO2 is not destroying the planet, but it may prove economically costly (including humanitarian crises) if positive feedback mechanisms cause temperatures to rise beyond what CO2 IR absorption can achieve by itself, an area I understand to have a wide range of uncertainty.
The solution is undoubtedly to try and stabilize CO2 levels. But the decision making process on this needs to be made on economic (inc. humanitarian considerations), not ideological, grounds.
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EDIT: A quick peek at Prof Reiter's bio shows that he is employed by a research organisation ("Annapolis Centre for Science-Based Public Policy") funded by Exxon-mobil.........Now I wonder why he might not like the idea of climate change???
But this doesn't invalidate what he is writing. Is he regarded as being an expert in his field? Are his views a reflection of the mainstream in his field? Are his complaints against the IPCC valid? Also his views as written in the link don't challenge the evidence for AGW at all, merely the politicization within the IPCC concerning his area of expertise.
Science thrives on a certain amount of diversity. Many paradigm shifts occur with the questioning of the accepted wisdom. I have no problems with energy companies funding research that runs contrary to current thinking on GW, as long as that in itself doesn't distort the research.
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But, but Roo! Have a read of Melanie Philip's Blog: http://www.melaniephillips.com/diary/?p=1468
That to me is not sound.
I also see Milibands blog has taken a few scathing remarks. To be expected considering he spouted off before watching the C4 docu..
http://www.publications.parliament.uk/pa/l...f/12/12we21.htm
The second link here is very interesting. The following point:
20. The issue of consensus is key to understanding the limitations of IPCC pronouncements. Consensus is the stuff of politics, not of science. Science proceeds by observation, hypothesis and experiment. Professional scientists rarely draw firm conclusions from a single article, but consider its contribution in the context of other publications and their own experience, knowledge, and speculations. The complexity of this process, and the uncertainties involved, are a major obstacle to meaningful understanding of scientific issues by non-scientists.
Is key, and drives most of my interest in the debate following the programme. To me AGW is almost certainly a factor in current temperatures and is significant. I think the science on this is solid. Even so I find the attitude of many, particularly politicians, media, green groups, and AGW proponents to be very worrying. Scepticism is good.
I can't comment on this particular scientists credentials, but if what he says is representative of his status, the current view on malaria and his treatment by the IPCC, then we should all be concerned that the IPCC is doing us a disservice. The issue is far too important to be politicized in this way.
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Care to back that comment up with anything, I'll gladly agree with it if you can otherwise my view is that it's plain wrong.
Not the same thing as BFTP was talking about but BBC Antarctic Warming, and certainly there is a lot of information out there suggesting the models can't be relied upon; which isn't particularly surprising, the models should be hard pressed to prove anything. AGW is backed up by a lot more than climate models.
Lots of information out there suggesting Antarctica isn't behaving as the models expect, but as always we need to be careful we don't cherry pick to suit our own preconceptions: it's unlikely a single paper or study will prove something one way or the other.
While I think it is difficult to argue against CO2 induced AGW, there is still lots of uncertainty, as in all things the devil will be in the detail, and some healthy scepticism for some AGW extremes is as it should be.
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I apologise for the unncessarily polemical tone of this phrase. My point is that sceptics have persisted in the argument that the lag of CO2 behind temperature as indicated by the ice-core records, shows that CO2 does not force climate: you are probably aware that this argument is fallacious, and would be irrelevant to the current situation anyway, as CO2 does warm the atmosphere. This is why I referred to it as a 'false prop'.
The fact that the ice core records don't demonstrate CO2 affecting global temperatures, is exactly what should be expected, and neither supports nor refutes AGW. Some of the arguments given to "explain away" this anomaly by AGW proponents are somewhat contrived, and as mentioned unnecessary. I don't expect this paper to show C02 leading temperatures, because under "normal" circumstances this shouldn't occur. Sceptics are correct to raise the issue, not because it disproves, but because it has been used a number of times to "prove" the link with AGW. The main evidence supporting AGW is that it is the only credible agent that explains the rise of the last 50 years, which has outstripped that possible by solar irradiance. Some healthy scepticism in the AGW arena should be welcome, proponents are far too dogmatic, and too reliant on models when we struggle to put accurate numbers on the basic mechanisms involved. A complete denial of AGW however seems as mad to me as the idea that we are likely to see a rise of 6 degrees nearing the end of the century.
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Quick note; more tomorrow. There is an open paper currently in 'Climates of the Past discussions' (awaiting publication, open to comment from outside) which is suggesting that the assumption that temperature leads CO2 in the ice core record is wrong. Originally, the case went that T leads CO2 by 800 years, with an uncertainty of ~600 years (sometimes also quoted as plus or minus 800!). This paper is offering an explanation of why this is probably a mistake, and concludes that it is possible that CO2 runs parallel with, or might even lead, temperature, in the ice-cores.
This is not a done-and-dusted conclusion; the paper is still under revision; the authors may be overlooking something, or misinterpreting the data. But it is a very interesting development in the field of palaeoclimate. If the authors turn out to be right, it blows yet another false prop out from under the feet of those who argue that CO2 doesn't matter (I'd also say that the argument using this is erroneous, anyway).
More on this tomorrow, I imagine.
:)P
What sort of language is "it blows yet another false prop out from under the feet"? It is the language of dogma and ideology. The paper has no significance yet, and like most of the papers published probably never will.
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very fine snow grains again this morning in Birmingham when I left my house at 7:10. It also looked like there had been more substantial precipitation in the night with many cars having a thin layer of snow on the screens and roofs. Very damp on the ground though. And it now looks like fine drizzle out the window.
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Very light snow showers here in Birmingham since 7:10, the snow grains are very small.
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It snowed in Birmingham/Solihull this afternnon between 16:30 and 17:00, small dry flakes that blew around in the wind - it was sunny at the same time though so nothing settled for long even thouigh the temperature fell to 1'C pretty quickly.
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A dusting in Birmingham when I woke up at 6:00am. However since then we've only had very, very light precipitation .
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Been snowing in Brum for the last half hour, no sign of settling in the city centre though
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A couple of very light snow showers here in Birmingham this evening. Smallish flakes, lasting only for half a minute or so each time, between 6:30pm and 6:50pm. Apparently something to do with the cloud layer stuck under the inversion?
Day time maxima of -2 here today as well, the coldest day I can remember since 1995.
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Blizzard conditions in Walsall according to my mate so you might get loads more as Walsall not far away from Birmingham
Walsall is to the west of us though, and the weather is coming from the east. We've had some nice snowfall here, it's just been too wet on the ground. I wish we had time to go to the clent hills today, but we don't :-(
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Its been snowing moderately here since lunchtime, not sticking on pavements as it's too wet, but doing better on grass and gravel
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Snowing in Brum, albeit lightly with fine flakes: got a dusting already though.
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nope stopped and melted.
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Weird heavy granular snow shower, looks to be settling again?
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Started snowing again here in Brum, lightish flakes, looks too wet on the ground to settle now after the melt from this mornings snow. Radar doesn't look too bad, we need heavier snow showers into the evening I think for any reasonable prospects of settling snow now.
The Great Global Warming Swindle
in Space, Science & nature
Posted
I agree with everything here. There is a line between AGW accepting advocate and AGW accepting sceptic, and I feel you're just on the one side and I'm on the other. All of our disagreements have really been about emphasis rather than fundamentals.
And I disagree with this: the sceptics jumped on this because the IPCC deliberately positioned Manns graphic; which they did because it was such a persuasive argument about the dangers of global warming. The science is so sophisticated and so uncertain, individual papers need to be taken with extreme care. Echoes that piece from the BBC and TWS's post.