This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
Objection:
It was just as warm in the Medieval Warm Period (MWP) as today, in fact Greenland was green and they were growing grapes in England.
Answer:
There is actually no good evidence that the MWP was indeed a globally warm period comparable to today. Regionally, there may have been places that did exhibit notable warmth, Europe for example, but all of the various global proxy reconstructions agree that it is warmer now and the temperature is rising faster than at any time in the last one or even two thousand years. Anecdotal evidence like wineries in England and Norse farmers in Greenland can never tell you a global story.
NOAA presents a whole selection of proxy studies together with the data they are based on and these can be found here. Specifically, they have this to say about the MWP:
"The idea of a global or hemispheric "Medieval Warm Period" that was warmer than today however, has turned out to be incorrect."
In specific answer to the "grapes used to grow in England" bit, I like to point people here as fairly solid evidence that grapes are in fact growing there now, denialist talking points aside.. If that is not enough, Real Climate did a remarkably in depth review of the history of wine in Great Britain and how reliable it is as a proxy for global temperatures.
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Sceptic.
"The Medieval Warm Period was just as warm as today" was first published here, where you can still find the original comment thread. This updated version is also posted on the Grist website, where additional comments can be found, though the author, Coby Beck, does not monitor or respond there.
"but all of the global proxy reconstructionn agree that...."
ALL of them???Are you joking?By making this statement you are either speaking in ignorance of the research or you are being knowingly dishonest.Which one is it?
Here are just a few of the studies that dont agree.
Loehle 2007
Moberg 2005
Baliunas&Soon 2003
Kim 2004
Lorenz 2006
Newton 2006
Thanks for those specifics tim. I'll try to look into them. I am interested to know why Loehle is only published in "Energy and Environmnet", not a very encouraging endorsement. Have you given them the same scrutiny you have given MBH98?
Moberg 2005 does not appear to be a reconstruction, but rather a comparison study. I don't have access to it.
Searching google scholar for Kim 2004 does not help me. Can't find a relevant hit for Lorenz 2006 or Newton 2006, not interested in Baliunas and Soon.
Thanks though for the specifics, I ask that question often but have not had relevant and specific papers cited before. You have given me one it seems.
"not interested in Baliunas and Soon."
Please explain why?
How would a warmer MWP affect estimates of man made global warming (MMGW)?
This topic was raised by Barrie across at the older thread but the discussion there appeared to arrive at two opposite conclusions. Without bothering with the data lets consider some possible causes. Suppose that the entire effect was due to solar variations. Then the climate sensitivity would be given by warming divided by solar forcing and this would have to be greater in order to account for a hotter MWP. This would also raise the warming produced by a given amount of man made carbon dioxide. This would certainly make the prospect of future MMGW worse rather than better. But that discussion neglects the possibility of unforced fluctuations analagous to the El Nino/la Nina cycle.
Suppose that the MWP was an unforced fluctuation (sometimes called a natural variation although this description is ambiguous). In that case a larger amplitude would also imply a larger climate sensitivity although the reasoning for this conclusion is rather less straightforward.
Once again the prospects of future CO2 produced warming would be worse. So why do the skeptics raise this issue? One reason is that they are not considering future MMGW but the attribution of recent warming. Since unforced fluctuations would have become larger, perhaps they can be made to account for the recent global warming? The trouble with this idea is that it also requires that the contribution due to all man made causes should be revised downwards. One difficulty with this approach is that the forcing due to CO2 is deduced from basic physics and is hard to revise. The revision would be especially hard because of the increased climate sensitivity. One way out would be to revise the negative forcings due to aerosols substantially upwards. This might cancel out the CO2 and reduce the man made contribution to the recent warming even after allowing for the raised climate sensitivity. But as soon as we turn our attention to the future, the whole outlook begins to change for the worse. The rising level of man made CO2 displayed in the Keeling curve is expected to dominate the aerosols and the effects of this domination would then be seriously enhanced by the raised climate sensitivity.
It is hard to avoid the conclusion that the original hockey stick of MBH with its very straight handle is the most "conservative" (least alarming) of the various ones available.
Geoff,I am afraid that your long winded explanation entirely misses the point.The MWP shows that
1]modern day temperatures are not exceptional.
2]the current warming cannot be attributed[in an historical context]only to CO2.
3]the earth benefitted from the higher temperatures.[the lower temps of the LIA caused much damage by contrast]
4]CO2 did not produce this warming.
Your whole argument about climate sensitivity is based on the flawed assumption that CO2 produces substantial warming.It does not-it only has a small effect as a greenhouse gas.
timwells have you ever seen an atmospheric transmission curve!!! CO2 band is huge and compete with H20 for impact. In the middle of the band, there is so much absorption than photons can barely make a few cm before beign absorbed. In dry air (in cold or high altitude), CO2 largely dominate.
But somehow using data sets where you take core samples from a couple of trees from a unique location tells us all we need to know? .... Or that we can accurately reconstruct the temperature history from that data.
Egads ... I don't think scientists are immune from that human tendency wherein, having invested their time and energy in a notion, they are capable of suffering criticism and admitting that there is error in their research. Being human, they will defend to the death their theories, even when clear errors are pointed out to them.
Do you expect Mann and co. to EVER admit error in their PC analysis? I surely don't.
About those Norse farmers: I've been reading some stories about finding these guys buried in the permafrost. So, it's likely that it was even warmer, if they are now still dealing with permafrost at those sites--as they wouldn't have been able to dig those graves if the ground was frozen, and had they been able to dig in the frozen ground, wouldn't the bodies have been preserved? So it was more likely even warmer than now--in Greenland at least.
Actually, I think, the answer should be: Why should it even matter that it was warm then?!. Where's the connection to today's problem?
This "it was warm, then" argument is used simply to insinuate that CO2 cannot be the reason, since it couldn't possibly have been the reason then (...this "argument" is often accompanied by the breathless statement that "the temperature was rising *before* the CO2 levels rose!!!!").
You can simply deconstruct the problem in the following way:
(1) Then:
Cause: Anything from solar radiation to aliens.
Primary Effect: Rising Temperature
Secondary Effect: Rising CO2-levels
Tertiary Effect: Rising temperature through greenhouse effect.
(2) Now:
Cause: Man.
Primary Effect: Rising CO2-levels
Secondary Effect: Rising temperature through greenhouse effect.
Tertiary Effect: Rising temperature through greenhouse effect.
Point in case: There's no need to question the evidence. It could well be in line with today's situation - it's just a shift in the line of argument: What might have been the secondary effect then, is simply the primary effect now. From there on, both scenarios are the same.
Does that mean that my argument is correct? That's my point - it doesn't matter! Just like the whole "it was warm, then" argument doesn't matter, too.
Hi Randomguy,
I agree, that is the best response to the implied argument behind "it was warmer in the MWP". I think I make that point elsewhere but it should be here too!
Yvan Dutil have you ever seen a graph showing the logrythmic relationship between C02 levels and IR absorbtion? Do you understand what saturation means? Just in case you have no idea let me explain C02 can only absorb a finite amount of IR once this point of saturation is reached it does not matter how much C02 is in the atmosphere C02 cannot absorb anymore.
By looking at the graph it is painfully obvious to all that the point of saturation is at about 280ppm of C02. Which probably goes a long way to explaining why global temps have dropped since 1998 whilst C02 levels have continued to rise.
By the way if you think the C02 band is huge have a look at how big the H20 (water vapour)bands are.
Randomguy - thanks for your Logic for Monkeys tutorial. But, to be honest, I think many of us skeptic, grandchild-hating pagans understand what you say already.
It is you that is missing the point - in answer to your question "Why should it even matter that it was warm then?!. Where's the connection to today's problem?", it is statements such as this by Coby (and many others):-
"I do however think that general understanding of the climate system can usefully constrain the range of possibilities for past global temperature trajectories enough to say it is really very likely that what we see today is not normal."
So long as AGW proponents continue to claim that today's temps are "not normal" (and, I assume, then say it must be due to CO2 as this is the only thing that is changed), attempts to determine the temperatures during the MWP will continue.
I think you people are refering to the Holocene Maximum. The Medieval Warm Period is a media term.
http://adsabs.harvard.edu/abs/2005AGUFMPP33B1563L
Hi Frederick,
The Holocene Climatic Maximum (or Optimum) was roughly 6000 years ago (or even more as your interesting link states). The term Medieval Warm Period appears commonly in the literature and refers to ~1000 years ago.
Randomguy,the logic of your argument is spectacularly illogical!Lets look at it.
[1]Then
Cause;Anything from solar radiation to aliens
Primary effect;Rising temperatures
Secondary effect;Rising CO2 levels---Rubbish,no historical evidence.
Tertiary effect;Rising temperature through greenhouse effect.---An incorrect assumption based on your false assumption in the secondary effect.
The reason that the MWP is significant is because of the claim made by many alarmists-primarily that the 20th Century is 'unprecedented'in terms of temperature,and that this is caused by CO2.The existence of the MWP demonstrates this claim to be false,and it logically follows that man made CO2 CANNOT be therfore isolated as the cause of the modern warming period. .
timobrienwells -
I'll repost this from the main post, since you apparently didn't bother to read it.
http://www.ncdc.noaa.gov/paleo/globalwarming/medieval.html
1) It was a predominantly regional effect.
2) It wasn't as warm as today (though it was warmer than the little ice age).
The existence of the MWP demonstrates this claim to be false,and it logically follows that man made CO2 CANNOT be therfore isolated as the cause of the modern warming period.
This is incorrect. You're making an error in assuming that an effect can only ever happen from a single cause.
http://en.wikipedia.org/wiki/Ignoratio_elenchi
Coby,
FYI
von Storch (2004)The centennial variability of the NH temperature is underestimated by the regression-based methods applied here [Mann et al], suggesting that past variations may have been at least a factor of two larger than indicated by empirical reconstructions. Frank et al (2005) The ring-width-based reconstruction substantially underestimates temperatures during the most of the overlap period with early instrumental data, with substantially lower values during the late 1700s and maximal divergence during the temperature minima around 1815.
D'Arrigo et al (2007)on divergence. The causes, however, are not well understood and are difficult to test due to the existence of a number of covarying environmental factors that may potentially impact recent tree growth. These possible causes include temperature-induced drought stress, nonlinear thresholds or time-dependent responses to recent warming, delayed snowmelt and related changes in seasonality, and differential growth/climate relationships inferred for maximum, minimum and mean temperatures.
Datsenko et al (2008) It is found that the Mann et al. reconstruction drastically underestimates low-frequency temperature variations, whereas the Moberg et al. reconstruction reproduces them much better, although with a certain underestimation rather than overestimation, as Mann et al. have recently argued.
Christiansen et al (2009) The underestimation of the amplitude of the low frequency variability demonstrated for all of the seven methods discourage the use of reconstructions to estimate the rareness of the recent warming. That this underestimation is found for all the reconstruction methods is rather depressing and strongly suggests that this point should be investigated further before any real improvements in the reconstruction methods can be made.
These studies show that low frequency variation is under estimated. Christiansen et al (2009) actually did a study into methodologies used for temperature reconstruction. The basis for your position is not supported. The Mossberg (2005) study also showed that Mann underestimated variation.
Hi Vernon,
Thanks for the citations. They seem to support the case that MBH reconstructions underestimate past variability and demonstrate that it is an area of very active research. I have no objection to either of them.
I do not see in these studies a contradiction to the central point of the post: "There is actually no good evidence that the MWP was indeed a globally warm period comparable to today.". Nor does it speak to the fact that what happened 1000 years ago is not necessarily relevant to what is happening today, and the evidence overwhelmingly suggests it is not.
Hi Coby,
I agree they offer no evidence that the MPW was a globally warm period for that, here are a collection of studies from North America, South America, Africa, Asia, etc that show MWP and LIA were a global events:
Millet et al (2009) The chironomid-based inference model reconstructed a July air temperature decrease of c. 0.7°C for the DACP and 1.3°C for the LIA compared with the temperature prevailing during the MWP.
Axford et al (2009) Much of the first millennium AD was relatively warm, with temperatures comparable to warm decades of the twentieth century. Temperatures during parts of the tenth and eleventh centuries AD may have been comparably warm.
Loehle (2007) The mean series shows the Medieval Warm Period (MWP) and Little Ice Age (LIA) quite clearly, with the MWP being approximately 0.3°C warmer than 20th century values at these eighteen sites.
Blass et al (2007) We found exceptionally low temperatures between AD 1580 and 1610 (0.75°C below twentieth-century mean) and during the late Maunder Minimum from AD 1680 to 1710 (0.5°C below twentieth-century mean).
Polissar et al (2007) Here we report a 1,500-year reconstruction of climate history and glaciation in the Venezuelan Andes using lake sediments. Four glacial advances occurred between anno Domini (A.D.) 1250 and 1810, coincident with solar-activity minima. Temperature declines of â3.2 ± 1.4°C and precipitation increases of â20% are required to produce the observed glacial responses.
Richey et al (2007) Two multi-decadal intervals of sustained high Mg/Ca indicate that Gulf of Mexico sea surface temperatures (SSTs) were as warm or warmer than near-modern conditions between 1000 and 1400 yr B.P. Foraminiferal Mg/Ca during the coolest interval of the Little Ice Age (ca. 250 yr B.P.) indicate that SST was 2â2.5 °C below modern SST
Mangini et al (2005) The precisely dated isotopic composition of a stalagmite from Spannagel Cave in the Central Alps is translated into a highly resolved record of temperature at high elevation during the past 2000 yr. Temperature maxima during the Medieval Warm Period between 800 and 1300 AD are in average about 1.7 °C higher than the minima in the Little Ice Age and similar to present-day values.
Mossberg et al (2005) According to our reconstruction, high temperatures - similar to those observed in the twentieth century before 1990- occurred around AD 1000 to 1100, and minimum temperatures that are about 0.7K below the average of 1961-90 occurred around AD 1600.
Tan et al (2003) The WTR agrees well with the HCC (Table 1), including the Medieval Warm Period (MWP) [Lamb, 1965] and the Little Ice Age (LIA) [Matthes, 1939]. (Vernon - Figure 3 shows MWP was +1C and LIA was greater that -1C from the mean.)
Yang et al (2002) General characteristics of temperature change in China during the last two millennia are most clearly expressed by the ââWeightedââ reconstruction (Figure 3). According to the ââWeightedââ reconstruction curve, temperatures in China were above average in AD 0â240 with two peaks around AD 50 and in AD 100â240. The peak at about AD 200 represents the warmest stage of the last two millennia, temperature was even higher than during the 20th century. (Vernon - Figure 3 shows that MWP was +1C and LIA was -1C but RWP was warmer than Modern warming)
deMenocal et al (2000) The most recent of these events was the Little Ice Age, which occurred between 1300 to 1850 A.D., when subtropical SSTs were reduced by 3° to 4°C.
I could get more but this does show it was not just an Atlantic basin event.
Now back to my original issue, namely that while those studies do not prove that MWP was as warm or warmer then the present, but the other side of that argument is that the temperature recreations can be used as a basis to estimate the rareness of the recent warming. It cuts both ways, there is no way to prove that current warming is exceptional since the methodologies used have been shown under estimate low frequency variation.
The MWP could very well be warmer than we are now.
Sorry, error in last post last paragraph should read:
Now back to my original issue, namely that while those studies do not prove that MWP was as warm or warmer then the present, but the other side of that argument is that the temperature recreations cannot be used as a basis to estimate the rareness of the recent warming. It cuts both ways, there is no way to prove that current warming is exceptional since the methodologies used have been shown under estimate low frequency variation.
The MWP could very well be warmer than we are now.
Coby,
Off looking for a current study? Looks like the whole AGW is running off the tracks.
I think the point to be made is not so much about the absolute warmth nowadays compared to the MWP or other warm periods, but about the speed of the climate change.
Possible underestimation of low frequency past climate changes can only support that the climate currently is changing exceptionally fast.
Vernon:
all you did was list random studies that HAVE NO CONNECTION WHATSOEVER. Some of them are referring to periods having nothing to do with the supposed MWP.
just listing a bunch of incongruous publications is meaningless at best.
Moreover, NOTHING listed addresses the point of whether CURRENT CO2 levels are higher than previous, and whether current levels are contributing to warming.
Ice core data DOES NOT LIE, unlike you bloody denialists.
Vernon,
There are two problems with your use of the MWP/LIA as points of issue for the current observed climatic change.
Firstly, despite your impressive listing of studies showing that climatic variation has occurred at numerous points around the earth at various times in the past, they do nothing to demonstrate that climatic change then was a global phenomenon. None of those studies demonstrate temporal synchronicity sufficient to provide conclusive evidence of a global event - and they are not supported by sufficient evidence from the southern hemisphere. There have been a number of studies (and you can look them up just as easily as anyone else) which suggest that, when southern hemisphere data is included, that the overall effect during the MWP is to make global temperatures slightly lower (0.3C) than the standard. There were a lot of regional events, but taken as a whole, the MWP/LIA were not simulataneous global phenomena.
However, even if we concede the point that the MWP/LIA were global phenomena, so what? Even if current temperatures are unexceptional in the context of geological climate variation, so what?
You cannot just say, "climate always varies", or "it was warmer in the past", because it is a non-argument. Of course climate always varies. No sane person would deny that. But that same sane person - if he is a scientist - then asks questions such as; "what does that mean? and "what causes the climate to change?'.
And guess what? We have searched for answers in the past, and when we have discovered the climate change culprit for both regional and global variations, it has always been some sort of natural forcing mechanism (and I won't bore you with a list here - you can do your own research).
Unfortunately, when we do the same search for an answer as to what is causing the current climatic change, ALL of those natural forcing mechanisms are absent. BUT - there is one forcing factor that we know causes climate change (we have known about it for decades and can demonstrate it experimentally) and which HAS been increasing dramatically in recent years; atmospheric CO2. So, we know the cause of the current climatic variation; it is atmospheric CO2 (and other gases).
Not only that, by analysing the isotopic characteristics of the atmospheric CO2, we know it is not natural in origin (volcanoes, undersea vents, etc), but undeniably anthropogenic (which should be obvious anyway, since we know humans are producing far more than we have in the past).
So, why is there an issue here? What don't you (and other members of the flat earth society) understand? How can we explain it any simpler to you?
Vernon.
And if you are attempting to be scientific by providing a list of papers that you believe support your position, you should be inclusive and examine all the evidence, even that which doesn't support your position.
You may want to look at this:
http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/CookPalmer.pdf
This is a paper on tree ring (yes, I know!!) reconstructions from New Zealand which shows temperature over the past 1100 years. It clearly shows temperatures during the MWP consistent with NH temperatures, and the authors state:
"The identification of a MWP sensu lato in New
Zealand adds an important new datum to the debate concerning
its large-scale occurrence and supports Broeckerâs
[2001] argument that it was indeed global"
However, they also state:
"Similar to the NH, this SH expression of the MWP is not homogeneous in time. Rather, it is composed of two periods of generally above-average warmth, A.D. 1137â1177 and 1210â1260, that are punctuated by years of below-average temperatures and a middle period that is near average."
And further:
"Of equal interest in the reconstruction is the sharp
and sustained cold period in the A.D. 993â1091 interval.
This cold event is easily the most extreme to have occurred
over the past 1,100 years. Interestingly, Gellataly et al.
[1988] reported evidence for a significant glacier advance in the Mount Cook area around the period 1100â950 BP."
I could go on about data from Antarctica and Australia, but hopefully you are getting the point.
Oh, and don't cherry pick the statements about "above average warmth" without also including the bit about "punctuated by years of below average temperatures", okay?
Mandas: Our sweet Vernon has a history of laundry-listing paper references that very frequently, when examined, don't support his position. This history goes back for some years now.
Yeah but at least he doesn't plagiarize ones that are wrong.
That honor is exclusive to our dear Crakar, far as I've seen.
Happy Holidays, all.
Methinks for the next several days I'll focus on my staple joys: gin and college football. The planet won't warm any more or less without my electronic graffiti.
Skip
Skip
You enjoy your gin and football and have a good xmas (or whatever you celebrate). Think I'll do the same with beer and cricket (although I have a soft spot for the Crimson Tide having spent a year there doing a masters).
And Merry Xmas to you to dhogoza - and of course to crakar, wherever you are (he and I live in the same city apparently).
I could get more but this does show it was not just an Atlantic basin event.
Once again the prospects of future CO2 produced warming would be worse. So why do the skeptics raise this issue? One reason is that they are not considering future MMGW but the attribution of recent warming.
See below article published by the US Geological Survey http://www.usgs.gov/newsroom/article.asp?ID=2372
Arctic Could Face Warmer and Ice-Free Conditions
Released: 12/29/2009 6:20:34 AM
Scientists documented evidence that the Arctic Ocean and Nordic Seas were too warm to support summer sea ice during the mid-Pliocene warm period (3.3 to 3 million years ago). This period is characterized by warm temperatures similar to those projected for the end of this century, and is used as an analog to understand future conditions....
Must raise the question, even with the blinkered pro-AGW lobby, why there was such high temperatures? It wasn't man made CO2, so why is this the only possible cause now?
Shame the single focus on CO2 distract from the other issue we need to investigate and resolve. I am passionate about my environment and leaving a positive legacy for my children, sad it is being railroaded by those that are not capable of thinking but just follow the masses.
You glossed over this rather relevant bit:
http://micropress.org/stratigraphy/papers/Stratigraphy_6_4_265-275.pdf
"During this time interval, the positions of the continents and the patterns of oceanic circulation were similar to modern, but mean global temperatures were 2 to 3°C warmer, and SEA LEVEL WAS ABOUT 25 METER HIGHER (Dowsett 2007)"
Considering we are on course for that level of warming this century, how does that square with this comment?:
"I am passionate about my environment and leaving a positive legacy for my children" -Mark.
"Must raise the question, even with the blinkered pro-AGW lobby, why there was such high temperatures? It wasn't man made CO2 - Mark.
Clearly it wasn't man made. And as to the causes of the mid Pliocene warmth, that has yet to be determined. Also note the the Pliocene actually encompassed a time where the Earth moved from a warmer climate to the cooler glacial/interglacial cycle.
"so why is this the only possible cause now?" - Mark.
Over a century of research and observations show the enhanced Greenhouse Effect is the only mechanism which fits the observations:
http://bartonpaullevenson.com/ModelsReliable.html
"sad it is being railroaded by those that are not capable of thinking but just follow the masses." - Mark
Now that you mention "not thinking" it's a wee bit silly that you bring up this study, you seem incapable of understanding the implications of it. Regardless of what caused the mid Pliocene warming the global temperatures suggest a sea level 25 metres higher than present. If that is what the Earth has in store over the next few centuries, it will be somewhat inconvenient.
Happy New Years, folks.
Mark:
DW knows sea level stuff better than I, but the argument you made (in earnest I assume) is another of my pet peeves that I see a lot from AGW deniers/mitigat-ors:
"It was really hot before. Therefore we don't need to worry about making it hot now."
Mark, even if it was way hotter in Time Period X by natural means, it does not follow that letting it get that hot again is going to be ok for *us*. Don't forget that climate change is typically associated with huge upheavals in the biosphere. Maybe the rats and roaches will do fine if if global mean temperatures go up 10 degrees in 200 years. But what about your great-great grand kids?
Skip
You seem to imply that the medieval warm period was only a North Atlantic/European phenomenon and yet as others have pointed out there seems to be a lot of evidence that contradicts this. How about this? Or do you dispute everything that the authors state
http://pages.science-skeptical.de/MWP/MedievalWarmPeriod.html
Also you seem to admit that climate change can occur naturally, which to be quite honest we all know it must do otherwise we would still be in an ice age, so I guess we both agree on that. However, according to you though, even if there have been scores of climate changes (including much more dramatic ones than we are experiencing now, into and out of ice ages) in the earth's history caused naturally, this present one and this one alone is catergorically 100%, unequivicably due to mankind's actions when all the others in the history of the earth were 100% not?!
Well, it looks like P.Jones concedes that the MWP could have been warmer than the present and may have been global, that the science is not settled. Sort of kills your talking point, but, I forgot, this site is not for the discussion of the science, just advocacy.
"However, according to you though, even if there have been scores of climate changes (including much more dramatic ones than we are experiencing now, into and out of ice ages) in the earth's history caused naturally, this present one and this one alone is catergorically 100%, unequivicably due to mankind's actions when all the others in the history of the earth were 100% not?!" - Jason.
Other than the current one beginning in the mid 18th century, do you know of any previous Industrial Revolutions in Earth's past?. Since 1750 atmospheric levels of CO2 have increased 37%.
"Well, it looks like P.Jones concedes that the MWP could have been warmer than the present and may have been global, that the science is not settled" - Vernon.
Only trouble of course is that the evidence doesn't support this, there is no globally synchronous warm period in the MWP. If there was it would totally contradict some denier claims of low climate sensitivity.
DP,
Look at my post from last May 15, 2009. Plenty of studies that are not based on tree rings from around the world show that the MWP did happen and was not just in Europe or the North Atlantic.
P.Jone agreed that the during the period of instrumental temperature readings, the warming from 1978 to 1998 was not exceptional and was there was no significant statistical difference between the three three recorded warming periods.
So how about more than just making statements, how about pointing to some studies that were not based on tree rings that support your position.
Oh, and P.Jones was right when he was able to hide data and break laws but now that he cannot, he is not to be believed. Seems someone is in denial.
"Look at my post from last May 15, 2009. Plenty of studies that are not based on tree rings from around the world show that the MWP did happen and was not just in Europe or the North Atlantic." - Vernon.
I have already been over all the studies cited at CO2science. Many of the studies they cite show evidence of century or centuries long cool periods during the time of the so-called MWP. I agree, from my reading, there appears to be a warm period throughout the world from about 900 -1500 AD, it just isn't synchronous.
"Oh, and P.Jones was right when he was able to hide data and break laws but now that he cannot, he is not to be believed." - Vernon.
My understanding of climate science is not based upon Phil Jones. I haven't even bothered to check what you claimed was true, but if so what evidence does he provide that the MWP was a globally synchronous event?.
"Seems someone is in denial." - Vernon.
We've long ago established that it is you Vernon.
I forgot that you don't bother to check, after all, religion is based on faith, not facts.
Must be getting warmer, look what just slid out from under a rock. Vernon, we have longer memories than you. Your "facts" have been shown to be false many times over, here and on other science blogs. Why do you only read anti-science garbage you find on denier sites? You are very foolish to believe such rubbish.
What Jones is saying is that there's insufficient evidence to definitively conclude either way, in regard to the MWP, because of a lack of southern hemisphere proxies.
Now Mann's latest paper on the MWP does seem to provide a fairly strong argument against there having been a global, synchronous MWP, but I doubt if he'd be surprised at Jones stating that the evidence is not definitive. Nothing mutually exclusive in the situation.
That's not quite the spin Vernon's putting on it ... the denialsphere is riding this as though Jones is saying that there's definitive evidence that there *was* a global, synchronous MWP and of course Jones is saying no such thing.
Here's Jones' exact words regarding the MWP. Not quite how Vernon spins it:
Seems to be something of a strawman argument here in that Vernon seems to think mainstream climate science says something different than Jones is saying.
Of course he also says this:
Regarding 1910-1940, we have good physical explanations for that warming period. The "its the sun, stupid" people should take note.
Here's the first sentence of Coby's original answer to the question:
Jones is saying nothing inconsistent with this statement.
Apparently Jones doesn't believe that the negative case is as strong as do some scientists, including Mann. On the other hand, paleoclimatology isn't Jones field. We don't know for sure if he's read Mann 09, for instance.
The twisted comments coming from the deniosphere are expressed in an interview Jones had with a BBC interviewer.
It has been spun by wattswrongwithwatt and other deniers.
Here is the actual interview, where we can see that Vernon has either not referred to it or is telling lies if he had read it:
http://news.bbc.co.uk/2/hi/science/nature/8511670.stm
What are you Vernon, a liar or just a stupid non-skeptical denier?
Lets see... Ignore Ian as he is a valued troll.
dhogaza,
The whole bases for current warming being exceptional is that the MWP was pretty much removed with Mann et al 98. Up until this point, there have been no AGW proponent from the Team, or those associated with the team, that were willing to admit that the MWP may have been warmer. Note that I did not say he said it was warmer, just that the science is not in on whether the current warming is exceptional or not.
Jones also agreed that the two other warming periods that we have instrumented records for are not significantly different from the last one.
So what we are left with is the fact that we do not know if the present is the warmest it has been in the past 1000 year, the last warming from 78-98 was not significantly different from the other non-CO2 attributed warming.
This pretty much kills Coby's talking point.
Vernon - you're not worth the trouble.
People can read the interview themselves and see how careful and nuance Jones is in his answers, nothing at all the way you spin them.
The interview of course includes answers that totally refute the spin you and other denialists are putting on the interview.
I'm not sure why he gave it, he should know by now that anything he says will be quote-mined and twisted out of any resemblance to what he actually thinks about global warming.
Yes, anyone reading the actual interview will see why you suggest people ignore the post that contains the link to the interview ...
Someone throw Vernon a rope, the hole he is digging for himself is getting deeper and deeper.
Vernon, do you misread what people say on purpose or is your understanding of the English language so poor?
Jones is not saying that "two other warming periods that we have instrumented records for are not significantly different from the last one" to mean that these two periods were warmer than now, he is saying that their rates of warming are similar. That has never been in dispute since we (that is scientists who have studied these things rather than deniers who believe anything which has been distorted to support their ignorance) know that there have been a number of different major forcing agents (volcanic, solar as well as GHG's) over the past 150 years.
However, during the past 50 or so GHG forcing has been the major forcing. Also the length of these earlier warming periods are much shorter than the present one. Thus the temperature is much higher now that it was 100 years ago.
dhogaza,
Yes, I recommend reading what Jones said and did not say. He did not say that the MWP was a regional event. He did not say that the present is warmer than the MWP.
He did say that it is not settled. That is a far cry from what Coby's talking point claims.
Which part are you claiming I missed?
Ian, you can always be trusted for name calling - i.e. a troll.
Never ceases to amaze me how the deniers avoid directly quoting sources and responding.
Ian you're just doing the Denier Shuffle--quote something out of context and then pretend you never did.
Sorry Ian I meant Vernon
Oh, what is that deafening silence, could it be that other than name calling, no one is going to address the fact that Jones just stated publicly, the science is not settled.
The silence is because you are wrong and have been told you are completely wrong (as usual). Why waste time on an idiot like you?
In Jones opinion, there's not sufficient evidence. Mann, NOAA, and others who specialize in that part of the science disagree. The available proxy data for the SH does not support the existence of a global, synchronous MWP, and in fact argues against it. Jones says it's not sufficient to rule it out, others say it does. They don't disagree about what the proxies say, just sufficiency.
Yet deniers keep insisting that there was a global, synchronous MWP despite the lack of any proxy data to support that position.
Since Jones is Vernon's new hero, I'm sure he agrees with the following statement in the BBC interview that has caused him to fall to his knees in worshipful pose:
Dhogaza:
Can you assist me with the following rather basic query: part of the response to Item E is: ". . . there's evidence that most of the warming since the 1950s is due to human activity". If one were to accept this statement at face value, being that 'most' of the warming is manmade, what caused the 'remainder' of the warming? And how significant today is that forcing?
Regards,
"I forgot that you don't bother to check, after all, religion is based on faith, not facts." - Vernon.
Yes, Vernon you provide no evidence of a globally synchronous MWP yet continue to insist there was. When the metadata is analysed, your MWP is found to be very regional in nature:
http://www.meteo.psu.edu/~mann/shared/articles/MannetalScience09.pdf
SbN, check this attribution graph:
http://en.wikipedia.org/wiki/File:Climate_Change_Attribution.png
It covers five major forcings over the 20th century.
That's extremely helpful, Coby. Thanks.
Personally, I'm a bit surprised that Jones's comment to Item E in #56 above is so conservatively stated. Perhaps there is an element of self-censure because of the scrutiny he is under.
Regards,
Firstly we need to establish a few facts, the hockey stick whether fraudulent or not is a study of the NH only.
Secondly we constantly here that the MWP and LIA was not a global event and i have constantly shown everyone this site:
http://www.co2science.org/subject/m/subject_m.php
Which suggests that the MWP and LIA may have indeed been a global event, the ONLY response i have recieved so far is the the website is a denier stronghold. Which is what one would expect from someone who has had his faith shattered to the very core.
Now onto Jones, after reading his interview i would like to draw your attention to this question and answer:
H - If you agree that there were similar periods of warming since 1850 to the current period, and that the MWP is under debate, what factors convince you that recent warming has been largely man-made?
The fact that we canât explain the warming from the 1950s by solar and volcanic forcing - see my answer to your question D.
It seems the belief is based more on an absence of knowledge than the presence of proof.
I'm back!! Did everyone miss me?
It looks like crakar missed me, or at least he was hoping I didn't come back and call him out (as usual!), because he is back on the MWP nonsense again. Not only that, he is lying (or has a VERY short memory), because he knows that I have provided ample evidence in the way of studies from New Zealand which shows a 100 year cooling period and increased glaciation, plus a 200 year cooling period from Australia, right in the middle of the NH MWP, which demonstates conclusively that it was regional NH event, and NOT a global phenomenon.
So... back in your box crakar. You have received more than enough actual evidence on the regional nature of the MWP - not simply assertions that it is a denialist myth (which it is by the way).
Welcome back Mandas how were the goats?
No i am not back on the MWP some else kicked off this old chestnut but like Don Chip once said someone has to keep the bastards honest.
Now by looks some of those goats have given you a hard time because you have come all nasty and hot under the collar. As i explained to Skip i dont like goats because they have beady little eyes and Skip does not like thier horns apparently.
Anyway your post is a little confusing, the apparent denier stronghold site i mentioned above has three papers on NZ temps and guess what they contradict everything you say which should come as a suprise. Maybe you should take a bit of your medicine and some research.
http://w.w.w.co2science.org/articles/V7/N19/C3.php
http://w.w.w.co2science.org/articles/V3/N34/C2.php
http://w.w.w.co2science.org/articles/V11/N53/C2.php
So when you are ready you can retract your last paragraph although i suspect you are not man enough to do that. Do you know the arabic translation of muniac is Mandas?
True, it might've been due to sky fairies rather than the known physical properties of CO2 coupled with computed climate sensitivity to increased CO2.
Show my a sky fairy, and I'll listen. Until then, I'll take science.
Shut up two dogs
I put a post on to refute Mandas's verbal attacks but alas it is lost in the ether.
Will try again but in light of the turds of disinformation from Mandas just like two dogs here all politeness has gone out the window.
Mandas you said
"Not only that, he is lying (or has a VERY short memory), because he knows that I have provided ample evidence in the way of studies from New Zealand which shows a 100 year cooling period and increased glaciation"
And yet we have 3 studies that prove you to either a complete liar or an incompetent fool. Which is it?
http://www.co2science.org/articles/V11/N53/C2.php
http://www.co2science.org/articles/V3/N34/C2.php
articles/V7/N19/C3.php
Add the front end to this link, Skip you will be please to know the dot, dot, dot trick does not work anymore.
But thats not all, we also have this:
Nthern Patagonia articles/V11/N43/C3.php
Atacama desert articles/V13/N6/C2.php
Sth Patagonia articles/V8/N23/C3.php
Antarctica articles/V11/N29/C3.php
Wst equatorial Africa articles/V10/N35/C3.php
Sth Africa articles/V3/N32/C2.php
Central America articles/V11/N38/C2.php
Indo Pacific articles/V10/N6/C3.php
Do i need to go on? Of course your defence will be but....but...but....CO2 Science works for big oil and....and..and...the IPCC says it isnt so.
Just more turds of disinformation designed to prop up your stupid beliefs
crakar
Thank you for those links. Have you read them? (I have - every one of them!!). And no, I am not going to put up a defence about CO2 Science working for big oil etc, because I don't know if that is the case (do you?).
Anyway, on to the papers.....
There is an interesting graph in Lorrey et al, which shows NZ Southern Highlands glaciers advancing (increasing) around 800 AD, then retreating around 1250 AD. They show a variable increase over the next 600 years or so, before retreating again over the past 150 years. I wonder what that suggests? It isn't precipitation, because the alluvial records indicate the sites surveyed were drier than usual at the time. With regard to temperatures, the authors state that the NZ climate is highly regional in nature, and there can be and are significant differences between the North and South Islands (and between the east and west coasts) based on oceanic and wind circulations. However, in your support, there is a suggestion of a brief overall 'spike' in temperatures of around 0.3 degrees around 1000AD, but it drops back to 'normal' about 50 years later.
Interestingly, all this agrees with alluvial sediment studies from Victoria which suggests that the climate around 1150 - 800 BP (around the time of the supposed MWP) was highly variable, but was COOLER than 1400 - 1200 BP. Here is a link to a study:
http://hol.sagepub.com/cgi/content/abstract/7/2/139
So, in answer to your question about whether I am a liar or an incompetent fool, I guess the answer depends on how you define either term. If by either, you mean someone who reads the original source material before commenting, then I guess you have worked out my character.
As for "turds of disinformation...."; I'm a bit confused, since I get most of my "disinformation" from links you provide yourself. The only difference is I actually read the sources. You should try it some time; science is fun!!
"because he knows that I have provided ample evidence in the way of studies from New Zealand which shows a 100 year cooling period and increased glaciation, plus a 200 year cooling period from Australia, right in the middle of the NH MWP, which demonstates conclusively that it was regional NH event, and NOT a global phenomenon." - Mandas
Yup, NZ study here:
http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/CookPalmer.pdf
"Of equal interest in the reconstruction is the sharp and sustained cold period in the A.D. 993â1091 interval. This cold event is easily the most extreme to have occurred over the past 1,100 years. Interestingly, Gellataly et al. [1988] reported evidence for a significant glacier advance in the Mount Cook area around the period 1100â950 BP."
Mandas & DW,
Yes i read them in fact there were more to pick from but i thought that was a large enough sample to prove my point.
So we have both produced peer reviewed studies which both support our views and contradict each others.
Does this suggest that at least one peer reviewed study is flawed? I think over all (that is apart from one study you cite from NZ) there is sufficient evidence to suggest that the MWP and possibly the LIA was a global event. Granted their effects may vary from one location to another in both hemispheres but this is to be expected, yes?
Mind you the only study you can find to support your view is a flawed study of the Nth Hemisphere. I dont have the stomach to kick off that debate again, i think Coby only leaves that thread open as a mark of respect for the dead. In Australian war terms Mandas the Hockey stick thread is right up there with the beach landing at Gallipoli, The Kakoda trail and the battle of Long Tan.
crakar
Huh!!!!!!????!!!
You suggest my only evidence is a flawed study of the NH - when I gave you a link to a study from Australia (is your skill in geography up there with your views on climate?), plus DW provided you with the link from my previous post from NZ (which I also think is in the SH). And not sure on what basis you think either study is flawed.
Plus you draw the conclusion that there is sufficient evidence for a global MWP - when we have given you evidence AGAINST such a conclusion.
You obviously DIDN'T read the ENTIRE studies that you referenced (it is highly probable you only read the abstract and the summary on the denialist site), otherwise you would have noticed the information that I gave you in my last post which contradicted the conclusions your denialist site drew.
And as far as your analogies go, I'm not sure why you would lump together a strategic failure (Gallipoli), a strategic victory (Kakoda TRACK), and a tactical victory (Long Tan). But I often have problems with your logic.
One step at a time Mandas,
Firstly, the only study you can cite is your beloved hocky stick for your views on NH, i have shown multiple studies that show MWP did indeed exist in the SH and the NH and yet you ignore all of them based on your one study which you your self admit has a "spike" so go fuck your self on that one.
My reference to the hockey stick thread was that it was a blood bath you fucking dickhead. Did you get trampled by a goat last week?
Better still bash it up your arse you stupid rude ignorant fool, gone a week and you come back all a huffin and a puffin. Dont address another post to me again you are no better than that two dogs idiot.
There that feels better.
To Dappledwater Post 36, good of you to not to mention my link to 50 or so examples of where it shows that the MWP was not just a North Atlantic/European phenomenon, still why don't you just ignore that as it doesn't fit your prejudices!
I will put it here again just so you and others can have another look. You might not like the name of the link but go into it and look at some of the data as there are studies from China, Chile, New Zealand and even Antarctica! showing the MWP wasn't isolated to N.Atlantic/Europe, collated by scientists, whose credentials look pretty solid to me. You can argue and pick small little points on minutiae in all of them, no doubt, but the point is if the AGW position is correct and we are on the brink of environmental armageddon then ALL studies should back the AGW position that this is the warmest the climate has ever been and they don't.
http://pages.science-skeptical.de/MWP/MedievalWarmPeriod.html
Your previous reply to me is nonsence, the question is not about the industrial revolution but whether climate change has occured previously! Also just because we have a current warm period it does not mean that this has to soley and exclusively be caused by the burning of fossil fuels and the increase of CO2 in the atmosphere since the Industrial Revolution started, it is not necessary that one is the cause of the other, you are looking for a reason to explain why there is a current warm period and this is your smoking gun. What if there was no need for a smoking gun and it is a natural climate cycle like there has been dozens of times. Or do you not believe there are natural changes of earth's climate? If so why aren't we still in an ice age? What got the earth into and out of that? Nature or mankind's actions? (if you talk about Milankovitch cycles or that technically we are still in an ice age in your reply you are missing my point).
I attach another paper that also makes for interesting reading
https://www.dmr.nd.gov/ndgs/Newsletter/NL99W/PDF/globlwrmw99.pdf
This again shows that if you look at data over a longer period (other than the 150 years or so that AGW proponenets always seem to use, or Mann's 1000 year, doctored, hockey stick) there is a huge amount of evidence that climate changes, both cooling and warming, occur naturally.
I feel this quote is very interesting "The entirity of the Holocene climatic history can be characterised as a sequence of 10 or more global-scale "little ice ages" fairly irregularly spaced, each lasting a few centuries, and seperated by global warming events. Up to the 18th Century we were in the (c300 year) Little Ice Age and now we are in the natural warming period after it (according to the IPCC, in 2007, global temperature has risen 0.74C in the last 100 years which would seem to fit fine in conjunction with an expected natural increase after the LIA). There is no need for a smoking gun from mankind to explain why we are experiencing a current warm period. Again rubbish the person whom wrote this or whatever, but these people will have staked their reputations on these findings so they must have checked and re-checked and treble-checked their data. If you are right about AGW, then papers like this and quotes like the one above shouldn't be being written!
Jason, tell us something that's not part of mainstream science if you want to refute mainstream science.
Climate change occurs naturally. There's not a scientist in the world who has ever argued otherwise.
Meanwhile, oh my, we have a geologist telling physicists they're wrong about atmospheric physics, apparently.
"To Dappledwater Post 36, good of you to not to mention my link to 50 or so examples of where it shows that the MWP was not just a North Atlantic/European phenomenon, still why don't you just ignore that as it doesn't fit your prejudices!" - Jason.
Yes, I admit I am prejudiced - towards "real" science and common sense. A medieval warm period where the warm episodes in the Northern and Southern hemisphere are separated by over 100 years (or more in some areas) is not a globally synchronous event.
I'd hate to see your attempts at solving a jigsaw puzzle, there'd be pieces missing all over the show and you'd be sitting there with a smug look on your face proclaiming you've finished it.
So I guess we have finally discovered the extent of crakar's debating skills.
"fuck you self", "fucking dickhead", "bash it up your arse" ????
Oh well, think I will go back to reading the science, and leave the personal abuse and the plagiarising of other's opnions to those who are obviously much more adept at it than me.
I have shown that there are many peer reviewed studies from every continent and every ocean on the planet which suggest the MWP was indeed a global event.
So we are left with a choice, we can either accept the findings of these peer reviewed studies or we can ignore them all and embrace one study from the NH which not only abolishes the MWP and LIA but has been proven to be flawed and use ignorance for the SH.
Multiple peer reviewed studies or flawed science and ignorance, its our choice.
"Your previous reply to me is nonsence, the question is not about the industrial revolution but whether climate change has occured previously! Also just because we have a current warm period it does not mean that this has to soley and exclusively be caused by the burning of fossil fuels and the increase of CO2 in the atmosphere since the Industrial Revolution started" - Jason.
Yes, we do know it has been warmer in earth's past. The association between high levels of atmospheric CO2 and global warm periods is well established:
http://droyer.web.wesleyan.edu/PhanCO2(GCA).pdf
"The correspondence between atmospheric CO2 concentrations and globally averaged surface temperatures in the recent past suggests that this coupling may be of great antiquity."
"A pervasive, tight correlation between CO2 and temperature is found both at coarse (10 my timescales) and ï¬ne resolutions up to the temporal limits of the data set (million-year timescales), indicating that CO2, operating in combination with many other factors such as solar luminosity and paleogeography, has imparted strong control over global temperatures for much of the Phanerozoic"
It is known that there is a natural Greenhouse effect that enables the Earth to be 33 degrees C warmer, than it would be in the absence of the effect.. CO2 is responsible for between 9 to 26% of the Greenhouse Effect. Since 1750 mankind has added an extra 37% CO2 to the atmosphere.
It's pretty clear why climate scientists acknowledge CO2 as the culprit.
To Dhogza 72, Well used Tactic A (so obvious though, I even put it in my update of 71) rubbish the person that writes the paper, oh no he is a geologist (well actually there are 3 of them the state geologist of N Dakota, another geologist and the Professor of Physical Geography at Stockholm University). I mean what qualifications have they got to possibly comment on what has occured in the past!
So you agree with me that climate change occurs naturally and has done since the dawn of time and that every other change that has occured has been natural, but where we differ is what you are now you are asking me to believe is that you say this one is definitely, catergorically and without question is man made and it could not possibly be anything else and there are zero natural forces involved. You can probably understand why I have huge doubts about that.
P.S Try not to use obvious Tactic B in your reply, rubbishing me.
To Dappledwater 73 and 76, No you are quite right, just ignore the link to the 50 or so studies by "real" scientists showing a warming period globally around the medieval times, just close your eyes and it all goes away. Still let me put it here again for you, as it seems very strong evidence to me, many with links to the actual papers that were written.
http://pages.science-skeptical.de/MWP/MedievalWarmPeriod.html
It is not my jigsaw puzzle that is falling apart, you are not even willing to look at all the pieces if you ignore the link above and others like it. The onus is not on people like myself, whom believe nothing much exceptional is happening with the climate and therefore are fine with the status quo. To justify the expense and sacrifices that individuals and governments are supposed to make the onus is on AGW proponents to prove that the current Global Warming in general is the big(gest) issue for mankind that we face and that we are on the brink of environmental armageddon, but for this to be correct then something special must surely be happening, however, if you are right then scientists should not be finding such results as (well it was warmer in the past globally and at different times it was colder in the past globally) outlined in the link above, but they do. Ignore them all you want, but there will be others. For AGW proponets, this flies in the face of all the doom-mongering they profess.
As stated, for there to be a major issue concerning the climate then this really should be the warmest period that mankind has ever faced on the earth, lots of evidence suggest it is not. What a great deal of evidence does suggest though is the fact that the earth was actually in a pretty cold period (the little ice age) prior to the present current warm period and the warming we see now would be logically the natural recovery from that, as has happened countless times in the past, and as outlined in my earlier link to the article written by the two geologists and the Professor of Physical Geography. It is also shown in this, which is a link to the graph submitted by Bradley and Eddy for the IPPC First Assessment Report 1990. (the upward curve we are seeing now is consistent with the one around 1000 years BP and nothing compared to the one around 10000 years BP, neither of which lead to mankind's doom)
http://www.tgdaily.com/files/images/stories/article_images/noaa/glacier…
You can also put every stat about CO2 emissions that you want, that is NOT the issue, the issue is Global Climate Change (anthropogenic or otherwise) and is mankind on the brink of disaster (that we are always told we are by AGW proponents) there are three questions that really matter and they are Q1) Is this the hottest that it has ever been for mankind, answer No (MWP, Roman Warm Period and Holocene Maximum were all as warm if not warmer) Q2) Is this the quickest rise that mankind has ever had to face, the IPCC stated in 2007 that global temperatures rose 0.74C in the last 100 years, looking at their own graph from 1990, answer No. Q3) Is the present CWP man made or not, well that is massively open to debate as we should expect a natural increase in global temperature after the Little Ice Age as has happened on previous occasions, however, whether it is or it isn't as the answers to Q1) and Q2) are no is it really that important?
PS Try also not to use tactic B as outlined in Post 77 in any reply.
"It is not my jigsaw puzzle that is falling apart, you are not even willing to look at all the pieces if you ignore the link above and others like it." - Jason.
It's my fault for not saving my link to another forum where I covered that CO2science nonsense in detail, but it doesn't take much reading of your link to prove my point, witness:
Patterson 1998 (Lake Eyrie, North America) - has warm period around 1000 AD (cold around 1400AD)
http://pages.science-skeptical.de/MWP/Patterson-1998.html
Wilson et al 1979 (New Zealand) - has warm period around 1400AD (and colder extending back to 1100AD
http://pages.science-skeptical.de/MWP/Wilson-1979.html
A warm period separated by 300 years between the hemispheres. That fact that you don't even read the studies you cite as evidence of your case is simply ridiculous.
Yeah, Jason.
As you are a new contributor to this forum I cannot resist putting my two cents in about this.
Its doubtful that you read the studies. I mean, I can't prove it, but I have seen this again and again and again from AGW deniers. Citing things that someone *says* disprove AGW without even being aware of the counter arguments as to what those sources mean. I call the process "dogma propping".
I also read your link--the one you were really keen on promoting. It says:
To evaluate the significance of the current warming, one must compare it with temperatures and variations that occurred prior to human activities. If the current warming is greater than that in the past, human activities may be a cause. If temperatures and variations in the past were comparable to or larger than the current warming, however, human activities may not be significant.
and later
âThe global temperature declined at least 10OC during the Ice Age (Pleistocene Epoch), which began two to three million years ago.â
(among other examples of extreme natural variation)
Your source's logic is so superficially confused I cannot believe you could not spot it. Jason, of course the planet has been hotter and colder in the past for any number of reasons. The questions is what is responsible for the warming *now*--which at least you're not denying is real.
Even disregarding his/your misunderstanding of MWP, your source is essentially saying, "See. Temps have changed anyway with or without us. Thus, modern temp changes are not necessarily caused by us. Case closed."
What this utterly ignores is the scientific basis for saying that *current* changes are anthropogenic. An analogy if you would indulge me:
My wife's aunt and uncle have seen the water table of their well reduced since a golf course was built in their home town and tapped into the aquifer to water the greens. By your logic, the golf course owners can argue, "Well, after all, we know that the water table level has fallen and raised naturally, historically;there have even been times in the past that it was *far* drier than it is now. This shows that this reduction is only natural variation. Its nothing worth worrying about."
Furthermore, this is a consideration I seriously doubt you've ever pondered: There is no rule that says only anthropogenic warming can hurt is. Even if modern warming trends are not completely attributable to CO2 (the IPCC uses a "90 percent" level of certainty that it is the primary driver) how is does that logically suggest it is ok to make it worse? The fact that the Earth was really hot in ages past does and supported life does not mean it will effetively support *us*.
Re: the IPCC's 1990 graph I know you are just parroting secondhand misinformation about that (we discussed it over at Oregon Petition with Tilo a few weeks ago but let me know if you are interested.)
".......I have shown that there are many peer reviewed studies from every continent and every ocean on the planet which suggest the MWP was indeed a global event. So we are left with a choice, we can either accept the findings of these peer reviewed studies or we can ignore them all and embrace one study from the NH which not only abolishes the MWP and LIA but has been proven to be flawed and use ignorance for the SH. Multiple peer reviewed studies or flawed science and ignorance, its our choice...."
Wonder if crakar is ever going to accept his own advice and accept the findings of multiple peer reviewed studies which demonstrate anthropogenic climate change as a fact, or whether he will ignore his own advice and believe blog posts from the flat earth society over science. I'm going for option B.
The hypocrisy in this place is astounding "here are some peer reviewed studies that proves me right". Well here are some peer reviewed studies that prove you wrong.
What studies? I dont see any studies, what you mean them studies from that website, oh that bloke is an idiot and that website is crap. Only my peer reviewed studies are worthy of mention because they agree with me.
Yours are just flat earth society mumbo jumbo.
crakar, they are trying to tell you that the peer reviewed studies that YOU provided do not support your claim of a globally synchronous MWP. You have not looked at them critically. The CO2Science websight does that all the time and they do it to fool people like you who are looking for things to cite without reading first.
None of the studies is a global reconstruction, none of them. When you look at them in detail you find results that specifically contradict that notion. They are regional constructions and they show that it was warm in one region when it was hot in another etc etc.
Even if we were talking about a different set of studies (which we are not) what would that say? It would say that there is no firm conclusion yet and you are not justified in claiming that the MWP was pronounced, global and at all like the current (20th-21st century) warming.
The best case you can make is that we can not rule out for sure that the MWP was global and pronounced, but that is the best case with little support. This is not equivalent to saying it certainly was global and pronounced.
Jason
I would like to thank you for the link you provided at post #78, to the map with the title "The Medieval Warm Period - A Global Phenomenon". It is probably one of the best summaries on the subject I have seen, and would make excellent reading for everyone.
Unfortunately for both yourself and the authors of the site, the graphs are the best argument I have ever seen AGAINST the idea that the MWP was global in nature. Go ahead, have a closer look for yourself at some of the graphs. Run your cursor over them and look at the expanded images, and take VERY CAREFUL NOTE of the peaks and troughs in the graphs. Go on, it's your link - take a look at it....
For everyone who couldn't be bothered checking, here are just a few snippets (all dates AD)
NZ: Climbs stedaily from 1100 to its hottest around 1380 before dropping around 1450
Chile: Coldest around 1150. Peaks around 1350 before dropping sharply at 1400.
Indonesia: Hottest from 1050 - 1250 with sharp decline at 1300.
Tornetrask Norway: Hottest from 900 - 1100 with sharp decline to coldest just after 1100.
Florida: Coldest around 800 AD climbing steadily to hottest at 1100.
Japan: Coldest from 900 - 1200 with a brief peak at 1300.
Southhampton Island Canada: Coldest at 1200 with sharp increase and hot peak from 1200 - 1300.
Makapansca Valley South Africa: Hottest from 1250 - 1300.
Germany: Hottest from 800 - 1000 and coldest from 1100 - 1250.
I have to ask, do you people EVER read the information before you post it here? This was your link, supposed to prove that the MWP was a global phenomenon, and it is the best demonstration that it was CLEARLY REGIONAL IN NATURE, with peaks and troughs occuring at different times at different locations.
You might also want to have a look as well crakar.
Coby,
So you fall under the "that website is crap" category then.
Yes you are right none of them are a global study that is correct, they are studies from several different geographical locations throughout the world and they suggest that each of these locations experienced some sort of warming in a similar time frame.
In fact there is no global study that i know of that shows us either way so what is your point?
Do you accept that the studies on CO2science are genuine or bogus?
Do you accept that these studies indicate that there was some warming (more in some than others) that suggests the MWP was in fact global? If not please elaborate.
If you have in your possession a study or group of studies then please provide a link to them. Oh and there is no point showing flawed studies as this tends to diminish credibility.
You might also want to have a look as well mandas
crakar
Funnily enough, I do have in my possession a group of studies that you ask for. See post #84 above.
As the saying goes, "read 'em and weep".
Oh - forgot to mention. That group of studies I have in my possession comes from CO2science, so I'm happy with your assertion that they are genuine. The only difference between you and me crakar, is that I just happened to read them, to compare the data and graphs to see if the temperature highs and lows were temporarily synchronised. Can you guess what I discovered?
(Spoiler alert.....they aren't!!)
The question related to Coby's assertion that none of the studies was global in nature, so i asked him to provide (if one exists) a study which was global. It would appear that nothing you provided qualifies, better luck next time.
Whilst i am responding to religious door knockers like Mandas i see neither one of you can or could be bothered in telling me why the studies i have shown are no good. I know Coby said "that cite is crap" but aside from that?
[coby here: carakar, stop being obtuse. Several of us of told you several times each that the studies are fine, they just don't say what you claim they say. Pretending not to hear that simple message does not make you look smarter.
The studies are legitimate, but they do not show warming at the same time all around the globe. They show that various periods of regional warmth happened for different durations and during different centuries. Therefore they seem to indicate no globally synchronous MWP. Period. ]
http://joannenova.com.au/globalwarming/hockey-stick/mwp-global-studies-…
Here is a wonderful picture listing what the studies from all over the world say about the MWP.
[ That link does not show the times of these warming periods so they do not support your position. Since they are coming from the same CO2Science source, have a look at the other link abouve that mandas praised. NOT a globally synchronous event!]
Now i know this cite is crap and you are going to tell Jo Nova is an idiot and the 752 scientists from 442 seperate institutes from 41 countries are all nut jobs, all i want you to do is tell me why they are all nut jobs.
What sick of looking at goat shit? Think you can
pass the time by annoying me?
Ok lets put an end to your little charade.
The MWP apparently spanned the years 800 to 1300 AD
The following links that you provide which show a peak in temps at the upper of the 500 year span.
"NZ: Climbs stedaily from 1100 to its hottest around 1380 before dropping around 1450"
Yeah thats pretty close, dont you think?
"Chile: Coldest around 1150. Peaks around 1350 before dropping sharply at 1400."
Once again that is a close match yes?
"Indonesia: Hottest from 1050 - 1250 with sharp decline at 1300"
And again the peak falls within the 500 year span yes?
"Makapansca Valley South Africa: Hottest from 1250 - 1300."
And again!
"Southhampton Island Canada: Coldest at 1200 with sharp increase and hot peak from 1200 - 1300."
Now you also provided a number of studies which showed a peak in temps at the lower end of the 500 year span.
"Florida: Coldest around 800 AD climbing steadily to hottest at 1100."
"Tornetrask Norway: Hottest from 900 - 1100 with sharp decline to coldest just after 1100."
"Germany: Hottest from 800 - 1000 and coldest from 1100 - 1250."
Now i am not sure what the point of your post was, if it was "to beat me in an argument" then i suggest you failed miserably. If it was to prove the MWP never existed or some other faith saving exercise i would once again suggest you failed miserably.
Looks like I have to say this VERY simply so crakar gets it.
You asked whether there was a group of studies regarding the global natuure of the MWP. I said yes, there is. It happens to be at CO2science, a site you refered to at post #85, and Jason linked to at post #78.
I went to the site, and I read ALL the studies (not just the abstracts) and I took careful notes. I then gave you some of the information I noted at post #84 - you have to read them yourself if you want more (I can't post it all here).
The papers all appear to be genuine papers. I have no problems with them. In other words, to answer your question in post #88, they appear to be good papers.
BUT... and here's the big BUT. The papers show quite conclusively that the MWP WAS NOT GLOBAL IN NATURE. You may read some of that information at post #84. If you want more, or you want to confirm (or deny) my findings, you have to READ THE PAPERS YOU KEEP REFERRING TO!!!!!!
Got it now!!!???
Is it only me, or does anyone else here think that crakar has completely gone over the edge with his denial of reality?
Seriously, you need help crakar.
Again, I have to apologise on behalf of my country(wo)men here, we ARE NOT all as stupendously stupid, ignorant and deliberately deceptive as Crackhead down here. The vast majority of Aussies actually realise the importance of this issue and how badly it has already begun to affect our abilities to produce agricultural goods as well as maintain our river ecosystems and coral reefs.
For fuck sake Crackar, when a group of events do not peak at the same time, they can NOT be said to be SYNCHRONOUS. Get it? It's not that difficult. If the "whole globe" went through a MWP then globally, the ups would go up together (pretty much exactly) and the downs would go down together. Not a series of completely different peaks and troughs spread over seven bloody centuries. Do you get it yet?
AAAAAaaarrghh!!!!
Crackpot, crackhead i will add them to the list Ok, thanks for the poll MattB. Mind you most people i know would laugh you out of a room. Admittedly i dont know a lot of poeple but i beleive you are being generous with the "most" claim.
Do you realise that KRudds ETS is now a white elephant this is his third go at getting it passed and it will fail again. People like yourself are the minority whether you like it or not.
Obtuse Coby? well i suppose thats the most polite way i have ever been called stupid (dull and blunt), thanks for that.
I will respond a bit more 2morrow its getting late bye for now.
In reply to Dappledwater 79 and Mandas on Point 84,
Do you believe that now all temperatures all around the world are rising now at exactly the same temperature at the same time showing uniformity everywhere and that each region has seen an exact 0.74C increase in the last 100 years. We are told were I live in England to now expect overall cooling due to global warming because of the supposed (imminent) failure of the gulf stream (eventhough 10 years ago we were in exactly the opposite postion after a few hot summers and we were all going to drown because of global warming). We are also told the temperature is rising quicker nearer the poles than anywhere else. We are also told the oceans are warming quicker than land. If we are experiencing global temperature rise it is not going to be uniform everywhere at the same time is it.
You are also arguing over semanitcs about times and dates to try to fudge the issue, as listed for the reasons above it is not necessary for temperatures to rise at the same rate with other areas at the same time. The author stated that there are very limited studies showing that the medieval warm period was just a N. Atlantic/European phenomenon, that is not true. There is a lot of evidence (you don't like the name of the site but it links to scientific studies) that shows that during medieval times areas outside of Europe also experienced warmer weather than we see now. It does not matter whether it was 1100, 1200, 1300, 1400 whatever. If those temperatures are higher there than they are now then that shows in that area that there was a warmer period than now during the medieval times for them.
Hate the site all you want (and as usual rubbish the posters), and twist and turn and try to get out of it but the problem for you is that for there to be this potenetially huge issue concerning climate change (man made or otherwise) it really needs to have never been warmer than it is. You are the accusers, you are the ones that are saying there is a potentially mankind threatening situation. For you to be right there should be NO studies that show that it was warmer than now, none, but there are lots of them.
Crakar's been around a long time, and it's not clear he's *ever* been on the reality side of that edge.
This is just ... what to say? I'm speechless.
Uh . . . uh . . . .
I'll try to think of something.
Uh . . . how 'bout them snowboarders?
I thought of something else to say.
Oh . . . my . . . God.
"Hate the site all you want (and as usual rubbish the posters), and twist and turn and try to get out of it but the problem" - Jason.
Isn't that was you are attempting to do?. It's been demonstrated that the MWP was not a globally synchronous event, using the studies you provided.
" for you is that for there to be this potenetially huge issue concerning climate change (man made or otherwise) it really needs to have never been warmer than it is" - Jason.
Wrong, the climate has been much warmer in the distant past, the polar ice sheets for instance only formed in the last 35 million years or so. But that does not alter the fact, that human infrastructure & agriculture is vulnerable to change, let alone the effect the current abrupt change may have on natural systems.
"You are the accusers, you are the ones that are saying there is a potentially mankind threatening situation." - Jason.
Nope, that's what the science implies. For instance:
http://e360.yale.edu/content/feature.msp?id=2241
"An Ominous Warning on the Effects of Ocean Acidification"
"A new study says the seas are acidifying ten times faster today than 55 million years ago when a mass extinction of marine species occurred. And, the study concludes, current changes in ocean chemistry due to the burning of fossil fuels may portend a new wave of die-offs."
You guys are tough nuts to crack.
First some acknowledgements
Dogs, its a thin edge.
Skip, didnt see the snow boards but saw the US belt the crap out of the Swiss in ice hockey.
Coby, i acknowledge your point about the pic having temps but no dates, i thought it would have been implied but yes i should have made a note of it in the post.
Moving on, i think we have made some progress since the last time we argued about this as no one here has brought up the hockey stick.
I think we all agree that at times the globe has been warmer than now in recent times but these warm periods may not have been at the same time. Maybe future studies will explain all of this a lot better.
I wanted to look at the studies and see if a region all warmed at the same time and then another region or was it all over the place, as yet i have not had the time. If and when i do i will let you all know or maybe someone else (with more time) can beat me to it.
I have a couple of retorical questions, firstly how accurate are the proxy data. i would assume we would have a higher error tolerance than usual, it is not like we are using accurate thermometers synchronised to an atomic clock is it.
Secondly, if some one from the year 3000 were to use proxies to see the temps today (because we gave all the temp info to Jones and he lost it)what would he see? Would he see the variations in temps from one region to another that we see today? There some stations mainly rural that show little or no warming for 100 years, would this show up in the proxy data? Interesting subject when you think about.
"Secondly, if some one from the year 3000 were to use proxies to see the temps today what would he see? Would he see the variations in temps from one region to another that we see today?" - Nutcrakar.
I'd expect future scientists would clearly see evidence of the simultaneous retreat in the Antarctica and Greenland Ice sheets.
To Dappledwater 99.
Good of you to be selective and completely ignore my first paragraph in 94 which was
Do you believe that now all temperatures all around the world are rising now at exactly the same temperature at the same time showing uniformity everywhere and that each region has seen an exact 0.74C increase in the last 100 years. We are told were I live in England to now expect overall cooling due to global warming because of the supposed (imminent) failure of the gulf stream (eventhough 10 years ago we were in exactly the opposite postion after a few hot summers and we were all going to drown because of global warming). We are also told the temperature is rising quicker nearer the poles than anywhere else. We are also told the oceans are warming quicker than land. If we are experiencing global temperature rise it is not going to be uniform everywhere at the same time is it.
Which would totally explain why any warming during the medieval period would not need to be exactly at the same rate at the same time all over the world like I said if the temperature was warmer in anywhere in an area in the medieval age than it is now, that is a sign that area was warmer there in the medieval times than it is now (if there are multi places all over the globe that this happened then this is not a localised European event like the first proposal mooted). Also if climate cycles instead of tens of years, lasted hundreds of years (which is what they seem to do i.e little ice age around 350 years) any time during the medieval years is part of the same phenomenon.
You can put a link to every study in the world you want about CO2 emissions and the effect that has but what really matters is what is happening to the climate and at present the IPCC says that the global temperature has risen 0.74C in the last 100 years, nothing exceptional at all and is easily within an expected range of what we should expect after coming out of the little ice age as the global climate recovers exactly as it has done naturally numerous (and every) time in the past.
and good of you again to miss this line to
For you to be right there should be NO studies that show that it was warmer than now (during human civiliation), none, but there are lots of them.
There are more and more of them all the time and your only tactic when dealing with such findings are to rubbish either a) the article or b) the person who wrote/draws light to it (does he work for the Oil industry (yawn).
I'd also quite like to know your opinion on this.
In my lifetime Around 1975 We were told that were going to freeze where I live we are on the brink of an ice age.
Around 1988 We were told were I live that we were on brink of being drowned by Global Warming due to man made actions (I can remember seeing a map of where I live being underwater in what is now the not too distant future, 2020)
Around 2005 We were told that were I live that we were going to freeze again due to the gulf stream being reduced due to sea ice melting in Greenland. Caused by overall (a?) global warming
And do you know what none of these things have happened, it is still as wet and as damp as it has always been in England!
You can make all the feeble excuses but this is what I know I have been told, almost totally contradictory things. Do you understand why people are sceptical? I used to believe in AGW but now I don't because not only are these predictions contradictory they also don't happen. All you do is twist and turn argue about minor technicalities (post 84) rather than actually even being interested in finding out and reaching the truth (I mean what is this nonsence about the MWP only being local to Europe of course it isn't, lots of other people on this thread have shown examples of this too), airbrush things out of history (bottom of post 80), rubbish anyone whom disagrees you (bottom of post 72), falsify and overexagerate figures (e.g Climategate). Do you understand why people are sceptical when you say believe us, this time (they are thinking just what are you going to be saying the situation is going to be in 20 years time) How can AGW proposers be allowed to flip flop so much?
"Good of you to be selective and completely ignore my first paragraph in 94 which was
Do you believe that now all temperatures all around the world are rising now at exactly the same temperature at the same time showing uniformity everywhere and that each region has seen an exact 0.74C increase in the last 100 years" - Jason.
Which is of course a silly strawman argument. Maybe if the Earth was a flat disc facing the sun, that could occur, so are you saying you are a paid up member of the Flat Earth Society?.
"We are also told the oceans are warming quicker than land." - Jason.
You sure are confused about a great many things. It's that nuance thing again, the specific heat capacity of water is far greater than air. Most of the heat is going into warming the oceans, which comprise 70% of the Earth's surface, but given it's higher specific heat capacity the oceans warm more slowly than the atmosphere:
http://www.cru.uea.ac.uk/cru/data/temperature/nhshgl.gif
Note how the Southern Hemisphere (predominately ocean) is warming more slowly than the Northern Hemisphere?.
Jason:
Do you believe that now all temperatures all around the world are rising now at exactly the same temperature at the same time showing uniformity everywhere and that each region has seen an exact 0.74C increase in the last 100 years.
No.
We are told were I live in England to now expect overall cooling due to global warming because of the supposed (imminent) failure of the gulf stream (eventhough 10 years ago we were in exactly the opposite postion after a few hot summers and we were all going to drown because of global warming).
Straw man. Who âtoldâ you this? Classic denier tactic: âSomeone who holds your position said something stupid. Therefore, your position is stupid.â
. . .if climate cycles instead of tens of years, lasted hundreds of years (which is what they seem to do i.e little ice age around 350 years) any time during the medieval years is part of the same phenomenon.
*What* âphenomenonâ?? The entire point, Jason, is that we now have evidence ofâplease get this very, very clear--*global* warming. There is *no* evidence of a *global* MWP. Canât you see this simple distinction? Yes of course there is current *regional* variation (i.e. poles heating faster, etc) but the overall global phenomenon is happening at an exponentially faster clip than the multi-centuries long stretch of time that you so loosely refer to as "the medieval years".
By your logic, you could arbitrarily choose *any* stretch of "hundreds of years", and use *any* finding for *any* region being hotter "then" relative to "now" to claim that current *global* warming is "within natural variation". In your case that stretch just happens to run from 900 to 1500 because we have studies showing that multiple regions had temperatures spikes within that broad range combined with your denier predisposition to believe in a MWP.
For you to be right there should be NO studies that show that it was warmer than now (during human civiliation), none, but there are lots of them.
A multi-headed monster of a straw man.
I donât believe you will, on second reflection, even agree with your own statement. Whether through design or honest error your statement is an effort to hide behind the vagaries of the word âitâ.
(1)Even if âitâ referred to the *global* temperature (i.e. there really *was* a globally synchronous MWP), that does *not* exclude the possibility of anthropogenic global warming *now*--that can only be resolved through other science. The existence of a MWP would certainly be a fair consideration in resolving that matter, granted, but it still would *not* be the silver bullet that deniers desperately try to make it.
(2)Alternately, if by âitâ you mean only ,âthe temperatures at *various* time periods in studies of *multiple* regionsâ temperature historiesâ, then youâre right back at your original problem, that you cannot use historic *regional* temperature variations as proof that a current *global* phenomenon is only ânatural variationâ.
There are more and more of them all the time and your only tactic when dealing with such findings are to rubbish either a) the article or b) the person who wrote/draws light to it (does he work for the Oil industry (yawn).
Utterly false, Jason. Dappled and Mandas are pointing out what *your own sources* do and do not say. Because you are either deliberately or honestly confusing the distinction between 1 and 2 above you just will not/cannot see it.
In my lifetime Around 1975 We were told that were going to freeze where I live we are on the brink of an ice age.
Again, by whom?
This is the same order of straw man you first used.
Around 1988 We were told were I live that we were on brink of being drowned by Global Warming . . . )
Who said this?
Around 2005 We were told that were I live that we were going to freeze again due to the gulf stream being reduced . . .
Who said this?
And do you know what none of these things have happened, it is still as wet and as damp as it has always been in England!
I am sure it is, Jason.
No one on this forum, in the IPCC, at the CRU, the Goddard Institute, or in the field of climatology is dumbfounded by your statement. I wonder if you have any idea why.
I used to believe in AGW
When and why? If it was because you were swayed by these inane straw man âpredictionsâ you mentioned then your alleged âbeliefâ was a fragile second-hand chimera that was doomed the moment you saw that England was âwet and damp.â
All you do is twist and turn argue about minor technicalities (post 84)
No, mate. The contributors to this forum are hard-bitten realistic academics and thinkers. They are not trying to baffle you with bullshit.
(I mean what is this nonsence about the MWP only being local to Europe of course it isn't, lots of other people on this thread have shown examples of this too) . . .
Youâre still utterly confused about the distinction between global and regional temperature patterns.
falsify and overexagerate figures (e.g Climategate).
I love challenging people to justify statements such as this. Consider the challenge issued. Youâre repeating, secondhand, something you read on a blog; you clearly have no idea what the âclimategateâ emails mean.
How can AGW proposers be allowed to flip flop so much?
Your understanding of âproposersâ conflates secondhand reports of false âalarmistâ predictions with actual climate scientists whose work is in fact the âquest for truthâ you say you want.
Look, Jason, if you really feel youâve been burned by âalarmismâ before, ask yourself what the sources of this alarmism were and whether you can use that to justify a wholesale rejection of climate science now.
Hi Coby
> "I like to point people here (http://www.english-wine.com/index.html) as fairly solid evidence that grapes are in fact growing there now, denialist talking points aside..
Ha ha ! Appreciate the joke Coby ;o)
No seriously, during Medieval times English wine used to be imported to France (just to say). It wasn't produced just for the eccentricity of it.
Regards,
Nils
Coby,
> "but all of the various global proxy reconstructions agree that it is warmer now and the temperature is rising faster than at any time in the last one or even two thousand years."
This is not true.
You're probably referring to MBH98 (the infamous "hockey stick"), but that's just one reconstruction amongst others.
Let's not dwell on the huge controversy surrounding this particular one and cite :
-Moberg et al. 2005 (http://www.ncdc.noaa.gov/paleo/pubs/moberg2005/moberg2005.html)
-Mann et al. (himself) 2009 (http://www.meteo.psu.edu/~mann/shared/articles/MannetalScience09.pdf)
Regards,
Nils
-
Skip,
(In your response to Jason)
Fair enough.
Although you will admit, I hope, that "temperatures being locally warmer, 'locally' being the whole northern hemisphere (See Mann et al. 2009), for a few centuries, is just a bit more than (I quote you) a 'regional' variation".
Regards,
Nils
MMGW skeptics deny MMGW and MMGW advocates deny MWP.
Just a thought.
@Nils
Not all temperature reconstructions that have ever been produced show that it is warmer now than in the MWP, but nearly all do.
Note that many of the reconstructions are Northern Hemisphere-only reconstructions. If you look a the Alley (2000) Greenland reconstruction, it's apparent that Greenland is not a good proxy of the NH.
http://residualanalysis.blogspot.com/2010/02/greenland-canard.html
Nils,
Your link http://www.ncdc.noaa.gov/paleo/pubs/moberg2005/moberg2005.html has a graph that clearly shows a MWP that was not as warm as current temps, and the abstract clearly states the same thing. Oh and the graph clearly shows the rise is much faster now than for the MWP or any other point on the graph. Perhaps you don't understand that the proxy reconstructions are fundamentally noisier than the modern instrumental record (and yet the current temp is still higher than the peak of the MWP noise). The broad smoothing applied to the proxy reconstructed temps is appropriate, but the modern instrumental record only requires 11 year smoothing to effectively remove the noise (even 5 year smoothing is pretty good). So I can safely say that the MWP peaked around an anomaly of 0.0 while the current anomaly is over 0.5C (global, 0.6 in just the northern hemisphere to compare with the MWP reconstruction).
Your second link shows basically the same thing, although Mann apparently believes he doesn't need as much smoothing for the proxy data, so there are some minor MWP (and prior) peaks over 0.1C.
I don't think any responsible scientifically minded person denies the MWP. I think the MWP went pretty much like those two reconstruction papers suggest. We are well higher than the MWP now, we're still going up, and we have an explanatory mechanism for the current warming that is well grounded in basic physics.
Yeah, Nils.
Most of us are familiar with both papers; I can't see how you thought they refuted Coby's statement.
The claim that "they were growing grapes in England" was always bizarre. It only makes sense if they don't grow grapes in England today. Of course, they do. Here is a link to the English Wine Producers Association web site: http://www.englishwineproducers.com/.
shargash
What's even funnier about this whole nonsense is that they grow grapes in Norway, Sweden and Denmark - even Finland - today.
http://www.scanmagazine.co.uk/2009/12/uncovering-the-past-present-and-f…
http://www.cityfarmer.info/2009/10/12/backyard-wine-makers-in-norway-at…
http://www.nytimes.com/2008/06/29/world/europe/29iht-finland.1.14068729…
I would have thought you could grow a decent Cabernet in England. Not sure how the Shiraz would go.
mandas
I can't wait for that Svalbard Rieseling. Give it another 20 years or so, and it should be just about right. I don't think I'll be around for the cab to ripen though, more's the pity.
The MWP was as warm as now (or even warmer)? Has anyone ever heard about the village Shishmaref? They are preparing to evacuate the whole village due to soil erosion, due to thawing permafrost. Also, the seals and polar bears have been moving away from the village, since the sea ice have disappeared, so the village can not provide food for themselves anymore. This community may be the first who must move because of Climate Change. The funny part of the story is that the village is standing where it always has been: for 2000-4000 years. Now, if it was as warm as now (or warmer) during the MWP, shouldn't this village had been destroyed back then? Obviously, it hasn't, but now the whole village is rapidly sinking into the ocean.
http://www.aaas.org/news/releases/2006/1206alaska.shtml
http://www.aaas.org/news/newsandnotes/inside137.shtml
http://www.aaas.org/news/releases/2007/0320townhall.shtml
http://www.shishmarefrelocation.com/
Hassol, S. J. 2004. "Impacts of a Warming Artic: Artic Climate Impact Assessment. Cambridge University Press. Cambridge.
Let me begin by saying that I am lazy and I haven't read nearly everything written here, however, I scrolled down to your 'Greenland' section because I wondered what your 'talking points' would be on that. It seems to me that you are more interested in convincing people that 'your side wins' and 'their side loses' than in real scientific inquiry. I really don't think anything of such major significance should be dismissed so readily with no mention of a boreal forest in Greenland.
Also, I do not think this should be a political issue. What has been done and is being done isn't right. Science should never become involved in politics or vice versa. True scientist would be much more convincing if they stayed out of politics, gave all scientist a voice, and allowed honest discourse. If there truly is a need for action, going about it politically isn't the best way. Personally, I do not believe that mankind will be able to change the climate (if it is a threat) at this point in our history, even if we try. I think it would be like one man trying to blow against a hurricane to keep it from reaching the coast.
jlue
First of all, if you are going to quote from a paper you need to provide a link or reference so we can read it to determine the accuracy or otherwise of what you are saying, and the credibility of the paper.
Second - so what? What does the alleged facts about forests and athropods living in Greenland 500,000 odd years ago mean? You need to do some analysis to tell us what you think it all suggests.
Thirdly - your concluding statements, while expressing your opinion, are based on nothing more than a personal view with a complete absence of evidence to to support them. Indeed, all the available evidence suggests the opposite. If you want to lecture us on the ethics etc of science, you need to show you have the slightest understanding of science and the scientific process. And you have failed to impress so far.
Hi jlue,
You do understand that the MWP was in the neighbourhood of 1,000 years ago, right? So what is the relevance of time periods 450,000 and 800,000 years ago to this discussion?
That said, I echo mandas' request for a bit more of a citation as it sounds interesting.
It looks like McShane & Wyner "A STATISTICAL ANALYSIS OF MULTIPLE TEMPERATURE PROXIES: ARE RECONSTRUCTIONS OF SURFACE
TEMPERATURES OVER THE LAST 1000 YEARS RELIABLE?" 2010 in next months Annals of Applied Statistics pretty much shows that the reconstructions are not reliable and using the same proxies as Mann et al 2008 and good statistical methodology, the MWP was as warm if not warmer that today.
Mandas, post 118
If claims of stupidity is stopping you from peer reviewing one study i would have thought stupidity would stop you from peer reviewing all studies.
If you cannot grasp the fact that empirical evidence has shown the models to be in error by up to 400% then i doubt you could grasp the fact that the climate can change even without human influence.
I suggest you do what Skip does and just plead ignorance.
It looks like the 'skeptics' are once again showing they are not skeptics. The 'citizen audit' of McShane and Wyner (involving people who have a firm understanding of paleoclimatology) has already shown a number of errors that an expert in paleoclimatology would never have made (seriously, calibrate a proxy against the hemispheric temperature?!?!). But then again, neither McShane nor Wyner have any discernable expertise in paleoclimatology.
crakar
You are right. I agree with you. Ignorance of a subject should preclude anyone commenting on it.
I am going to follow your recommendation. From now on, I will restrict my comments to subjects that I am an expert in. So I will only comment on matters related to wildlife and their ecosystems.
And to be consistent, I am going to ask that everyone else does the same (including you of course). Fair enough crakar?
From post 118
You said
"First of all, if you are going to quote from a paper you need to provide a link or reference so we can read it to determine the accuracy or otherwise of what you are saying, and the credibility of the paper."
So let me get this straight you can debunk a study by Spencer because of his views on ID, you cant comment on a study which shows the models to be in error by 400% because you dont have the math skills but you are asking jlue for a reference so you can determine the accuracy and credibility of the study they are quoting from, WTF!!!!.
All i ask is for consistency Mandas, either you have the ability to peer review every study ever produced in every field or you have no idea what you are talking about.
People offer their opinions and you jump on them from a great height as if you know better, your arrogance is astounding.
I think it would be a good idea if stopped pretending to know everything about everything and just stick wild life matters as for myself i will continue to post my opinions where i see fit and the more you dont like it the better.
crakar
Thanks for that. Just needed to have confirmed what I already knew. Skip, coby, chris, dw, myself et al all provide input based on knowledge and expertise. You will just keep giving us your ill informed opinion.
Nothing will change.
either you have the ability to peer review every study ever produced in every field or you have no idea what you are talking about.
An absurd dichotomy. I don't believe even you believe your own statement, Crakar.
Vernon @120 - McShane & Wyner replaced Mike Mann's "hockey stick" with an almost identical hockey stick, and deniers are excited about that because???
http://scienceblogs.com/deltoid/2010/08/a_new_hockey_stick_mcshane_and…
Dapplewater,
If you actually read the paper, you would not make such a foolish statement. Have you read the paper or are you just quoting the talking points from deltoid?
Hey Vernon buddy, I'm not the one that claimed "the MWP was as warm if not warmer that today" @ 120. Read the paper linked to at Deltoid, and note that McShane and Wymer's reconstruction contradicts your assertion. Ouch!.
Dappledwater,
Sorry but it does not.They found:
"In other words, our model performs better when using highly autocorrelated noise rather than proxies to âpredictâ temperature. The real proxies are less predictive than our âfakeâ data. While the Lasso generated reconstructions using the proxies are highly statistically significant compared to simple null models, they do not achieve statistical significance against sophisticated null models."
Additionally they said:
"Consequently, the long flat handle of the hockey stick is best understood to be a feature of regression and less a reflection of our knowledge of the truth."
In conclusion:
"While we are able to replicate the significance tests in Mann et al. (1998), our Table 2 shows that our model does not pass âstatistical significanceâ thresholds against savvy null models. Ultimately, what these tests essentially show is that the 1,000 year old
proxy record has little power given the limited temperature record. ... The final point is particularly troublesome: since the data is not easily modeled by a simple autoregressive process it follows that the number of truly independent observations (i.e., the effective sample size) may be just too small for accurate reconstruction."
It really helps to read the paper and not just pull out a single graphic and crow that it has a hockey stick shape.
http://rabett.blogspot.com/2010/08/flat-new-puzzler.html
Check out the updates, particuarly from Martin Vermeer ( http://www.eoearth.org/contributor/martin.vermeer )
I appreciate it Chris, but I'm in a position where I don't fully get the paper *or* the critiques.
I'll be running two-by-two contingency tables while you guys sort all this out . . .
It's certainly an odd paper alright Vernon, it'll be savaged in the peer review process, no doubt about that. Paleoclimatology involves a bit more than just statistical nous, a lesson the authors are about to learn.
Particularly odd is page 5 - "With so much at stake both ï¬nancially and ecologically, it is not surprising that these analyses have provoked several controversies........."
Errrr dudes....... if the MWP was in fact as warm globally as today, or warmer than today, that infers greater climate sensitivity, than currently understood, and greater urgency to cut greenhouse gas emissions. Sheesh!.
Yeah and when I read that part I thought to myself, "Well, at least they aren't trying to disguise their political motivation."
But as a non-expert I'll be a sport and wait until something resembling a consensus emerges around the paper. Its bizarre how being an AGW believer puts me in the awkward position of always rooting for the opposition.
Dapledwater,
The paper has been though peer review. The deno's should not have problems, they used the same proxies used by Mann 08. The only thing they bring to the table is actual statisticians instead of non-statisticians misusing stats.
I do not see how you can infer that climate sensitivity is greater when there is nothing to show that current warming is outside of natural variation? While I agree an increase in CO2 will cause warming, there is nothing that indicates the sensitivity.
Has anyone else noticed that this paper is all about a reconstruction of proxy temperatures from the northern hemisphere? I don't want to point out the obvious problems with this, particularly for those of us who just happen to live in the other half of the world that seems to be completely forgotten about in this discussion.
We have been over the MWP ad nauseum, and anyone who approaches it honestly will realise that the MWP was NOT global in nature (refer to some of the posts prior to #100), so to try and infer that the medieval period was warmer than today is politically motivated nonsense. And to try and draw that conclusion based on a data set that excludes half the world is crap science. But then again, what else would you expect?
Vernon,
This study will be published in time to be included in the next IPCC report what are the chances it will get 5 full page spreads?
mandas,
Have you read the paper? Did you notice that the reconstruction uses the same proxies that made up Mann 08? You know "Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia"? If the proxies were good enough to do global for Mann, what changed that makes them not good enough for this paper?
"While we are able to replicate the significance tests in Mann et al. (1998), our Table 2 shows that our model does not pass âstatistical significanceâ thresholds against savvy null models. Ultimately, what these tests essentially show is that the 1,000 year old proxy record has little power given the limited temperature record. ... The final point is particularly troublesome: since the data is not easily modeled by a simple autoregressive process it follows that the number of truly independent observations (i.e., the effective sample size) may be just too small for accurate reconstruction."
Now what was the basis for saying MWP was not global?
Vernon
Yes, I have read the paper - but you should have been aware of that because I pointed out to you (and everyone else) that the paper was only referring to northern hemisphere proxy reconstructions. Did you not pick up on that?
And if you want to know my basis for saying the MWP was not global, scroll up.
I remember reading somewhere in the fine print that Manns hockey stick was based purely on Nth Hemisphere proxies, therefore if this new study uses Manns data only then it must also be purely a Nth Hemisphere study.
Mandas, this is connected to our other conversations. My opinion on this is that if you have to torture the data to show the MWP did not exist only to be outdone by a new form of torture are either of these studies considered accurate?
crakar
Do us all a favour please. Go away and read this study then come back and discuss.
I will give you a hint - if you think this study 'proves' the MWP then you have completely misread it. It specifically says that it cannot confirm it either way, because the information is not available to do so. Do you understand that. This study does NOT prove the existance ot a MWP. In fact, have a good, hard look at the quote which has been bandied around here several times, most recently at post #130. It says, quite clearly:
"....While we are able to replicate the significance tests in Mann et al. (1998), our Table 2 shows that our model
does not pass âstatistical significanceâ thresholds against savvy null models. Ultimately, what these tests essentially show is that the 1,000 year old proxy record has little power given the limited temperature record....we conclude unequivocally that the evidence for a âlong-handledâ hockey stick (where the shaft of the hockey stick extends to the year 1000 AD) is lacking in the data. The fundamental problem is that there is a limited amount of proxy data which dates back to 1000 AD; what is available is weakly predictive of global annual temperature...."
Do you get that? They are critical of the 'hockey stick', not because they think it is necessarily wrong, but because they believe there is insufficient data available to provide statistically significant trends over the period. Simply, the data is not there to conclude either way.
This is where a science education would have come in handy for you crakar. IF you had read the study (which you haven't), you would have been able to understand what it is saying. But you don't.
They say this quite clearly by the way, you don't have to interpret it:
"....The MWP is believed to have occurred from c. 800-1300 AD (it was followed by the Little Ice Age). It is widely hoped that multi-proxy models have the power to detect (i) how warm the Medieval Warm Period was, (ii) how sharply temperatures increased during it, and (iii) to compare these two features to the past decadeâs high temperatures and sharp run-up. Since our model cannot detect the recent
temperature change, detection of dramatic changes hundreds of years ago seems out of the question...."
The authors of this study praised the work of climate scientists such as Mann:
"....Nonetheless, paleoclimatoligical reconstructions constitute only one source of evidence in the AGW debate.
Our work stands entirely on the shoulders of those environmental scientists who labored untold years to assemble the vast network of natural proxies...."
Further, the study also confirms that the instrumental record clearly shows unusual warming recently:
"....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...."
So - I will give the same tip I have given countless times before. DO SOME RESEARCH, AND ACTUALLY READ WHAT YOU ARE ATTEMPTING TO QUOTE FROM. Relying on the interpretation of other deniers just makes you look more of a fool than you can manage all by yourself.
So i back you up (not Vernon) on your statement that this is a study of Nth Hemisphere and throw in a question about the torturing of data in both studies and you respond with another long winded personal attack complete with sticky caps lock button!!!!!!!!!!!!!!!!
You really are a sad old fucker arn't you.
We have had this conversation before. I am not sad - I am a very happy person.
But your question (??) was more of an allegation:
"....My opinion on this is that if you have to torture the data to show the MWP did not exist...."
I'm not torturing any data. I am just quoting from the paper and asking why you are referring to it if you haven't read it.
Sad old fucker?
Um, for the record, some of my dearest friends are old fuckers of the saddest variety. I also suspect that we are all destined for some form of sad, old, fuckery one day; be careful what you disparage.
skip
As long as I am still a fucker, I will never be sad.
The T-shirt I send you for Christmas will be imprinted with those very words.
SOF,
"Do you get that?"
What i got was
Manns study used statistical manipulation (not in a bad way) to establish the hockey stick shaft shaped graph, then along comes another study which uses another form of statistical manipulation to show that the data he used was not good enough. Therefore we are no further down the track of enlightment than we were 100 years ago.
You however sitting way up there in your ivory tower could not be bothered to actually read what i had said and no dont come back with "well i did not understand". You are a rude, arrogant SOF and it will be the last time i ever back you up in any way shape or form (re Manns study was not global).
And as for your little lap dog..... well it must be way past his bed time i will blame his ignorance on lack of sleep.
Good riddance to you both
SOFs of the world unite.
I'm trying to determine if I'd rather be a SOF or the lapdog of one.
Maybe Craker is right; I should sleep on it.
So.....what no apology for misunderstanding my post and simply hurling abuse at the behest of Mandas.
Dont get me wrong i dont expect Mandas to admit to it but i did expect more from you Skip but hey just when you think you know somebody......
Have a good noght sleep.
Rather touchy aren't we crakar? For someone who abuses, fails to read posts, never apologizes for errors, never answers simple questions while demanding answers to your own, and just plain acts in a disingenuous and dishonest manner, you sure don't like it when you get a miniscule taste of your own in return. Maybe its just that time of month
The lapdog has to say aye.
Lighten up, Crakar. No one's called you a fucker--sad, old or otherwise.
Lighten up, Crakar. No one's called you a fucker--sad, old or otherwise.
You have got to be kidding me, many posts ago i asked if the models are out by so much what are the ramifications of this. But none of you morons wanted to discuss this instead you launched a smear campaign in an attempt to reduce my credibility whilst simultaneously over exaggerating your own as if to suggest a wildlife scientist a whatever the hell you are Skip are the worlds experts on the subject of all things important.
And now the same cast of dodgy believers are at it again, you are not interested in discussing what these two studies my suggest you are simply defending the faith. In fact Skip i would suggest that you have no right to sling shit at other people because you have no opinion of your own. Your only contribution to this site is about narratives and the statement "I agree with what he said".
In other words you make no meaningful contribution at all. Mandas you simply ooze ignorance and arrogance you are of the belief that you are right about everything even though you know about as much as anyone else here and no dont come back with "but....but...but i am a scientist". Dont forget to let the dog now and again so he can take a piss.
crakar
Skip said it best - lighten the fuck up!
You want to discuss these two studies? Ok, let's discuss them. Your first task is to go away and read them for the first time. And don't bluster and rant and rave about me smearing your credibility, everyone here knows that you have NOT read the studies yet. That is not unusual - we all know that your contributions to this blog rest solely on your ability to cut and paste the opinions of others from various websites. So stop acting as if we somehow besmirched your good character. It is not skip or I that have no credibility or that our opinions are not supported by evidence - that is your job.
In the meantime, my views on both studies are clear. I have posted them a number of times, and if you are too damn rude to actually read what I had to say, then my supposition about you having no credibility has been amply demonstrated. But just to refresh it for you, in regard to the McShane and Wyner paper, have a look at post #141. I think that's pretty clear. The paper changes nothing except that it suggests that the proxy data sets for the northern hemisphere are inadequate to provide statistically significant, accurate temperature reconstructions over the past 1,000 years. It does not say that the reconstructions are wrong (just that the data sets are statistically insignificant, and it does say that the instrumental record clearly shows recent, unexplained temperature increases. When you have read the paper, come back and tell us what YOU think.
With regard to the McKitrick and McIntyre paper, I will continue to state that I do not understand it, and will reserve judgement on it. IF it is accurate - and that will only be determined following review by experts (ie not me and certainly not you, peer review is only the FIRST step in that process (which you would know if you had the slightest understanding of the scientific process), it may well be that some of the prediction models will require modification. Once that is done, we will have a clearer indication of any revised forecasts. But we will not know what the paper means until, a) the paper has been verified, and b) any verified findings of the paper have been incorporated in the appropriate models. You never know, it may indicate that climate will warm slower than predicted by some models, or, because of the complexity if the system, there may be other consequences we haven't considered.
Particularly with regard to the M&M paper, both skip and I have refused to accept it or reject it, because we have insufficient knowledge to do so. And I have asked you repeatedly why you have apparently accepted it as accurate. If you want to demonstrate that you have the slightest degree of credibility, you would answer that question openly and without evasion. So far you have consistently refused to do so.
How's that for discussing the issue? How about you now contribute to the debate by telling us all what you think?
whatever the hell you are Skip are the worlds experts on the subject of all things important.
I can't claim that, sadly.
I can claim I've never plagiarized incorrect scientific argumentation. Is that a start?
Oh - and crakar. You are fond of criticising the fact that I am a wildlife scientist, and am therefore not qualified to comment on climate issues etc. I want to know if you stand by that criticism.
That should not be a hard question to answer. Do you stand by your view that I should not comment on climate issues because I am not qualified in that field?
Mandas,
The papers have been peer reviewed. Both the MMH 2010 and MW 2010. I also have not seen any place where a statistician has pointed out any flaws with these works.
Vernon
Thanks, but I was aware of that. It just confirms what I said at post #154.
154,
From what i have read of the MWP paper it appears that it is saying that from the available data you cannot accurately reproduce the past 1000 year temps.
As i said in a round about way in post 140 (you know the post where you read what you wanted to read and then went nuts) we have a study claiming that there was not enough available data for Mann to create the stick, but yet just enough data for them to say they dont know what shape it should be. Eventually a new method of statistical torture will be invented and the past 1000 years will look like a tennis racket.
As for the other study, my beef with you on this is not that your opinion is "i can neither accept or reject it" but it is with your opinion that everyone else should think just like you. I do understand the scientific process of which you speak regardless of how stupid you think i am.
156,
Mandas i only critise you about being a wild life scientist because it pisses you off much the same way you say things to me. Wildlife scientists play a vital role in understanding the environment and the more we have the merrier and i am sure you are very good at what you do. I acknowledge that what i said was intended to piss you off and this was not the right thing to do.
In regards to what you can and what you cannot comment on, if you want to comment on something then fill yer boots Mandas. Thats the whole point of being here, if we were to take the attitude of "you cant comment on such and such because your just a (insert skill set here)" then it would be a bloody boring place.
My attitude here is let everyone comment when they want on what they want, if i want to say this study shows the models to be wrong then you can say "not yet it needs to be verified etc" Ok fine lets wait but in the mean time lets talk about what it means if it is verified or something along those lines.
Dont take everything i say as an affront to AGW, maybe i could have worded my posts better i will grant you that. One study will never convict or clear CO2 we all know that.
One last thing I have one question that i have asked before which must have got lost in the process which i would like both you and Skip to try and answer and if i have left a question unanswered then let me know.
You state the paper must be verified which i accept but let me ask you again have the models been verified in the same way and how was this done?
crakar
Thank you for your reasoned and thoughtful comments. It would all probably be a lot better if we were all a little more civil at time, and I will accept my share of the blame in that regard.
I don't believe everyone should think the same as I do - but my ongoing beef is that people should refrain from criticising things that they both do not understand, and which they haven't even read. I also believe strongly in a rational and logical approach to understanding things, and that when the evidence suggests that an opinion is wrong, then you (anyone - not you in particular) should be open minded enough to accept that you may have been mistaken. Its hard to do this - which I know from personal experience - but it is also the right thing to do. I hate it when people who do not know anything about my particular subject of interest think they know better than me - and I project that same concern into areas such as climate change. Why is it that 97% of experts in the field accept climate change, but half the population thinks they know better? Imagine if people who had no background in what you do for a living told you that you were wrong or involved in a conspiracy etc. You would be rightly pissed off - so why should you (or anyone) think your opinion on climate change is right and the experts who have spent decades working in the field are wrong?
Anyway, as far as these studies go, we both agree that the 'hockey stick' study actually does not really change anything, but it does suggest that the data may not be significant enough to draw definitive conclusions. I know that many people dispute that, and that is something they can argue between themselves. To be frank, I have always had concerns about some proxy reconstructions (ask dhogoza, we had a very frank exchange of views on the subject some time ago), but in the end I don't think it changes much. The real issue is current warming and what is causing it, not what may or may not have happened a thousand years ago.
The other study is more problematic. You may not be aware that neither study author has any expertise in climate science. McKitrick is an economist and McIntyre is a geologist, so if you have concerns about my qualifications to comment, you would have to have the same concerns about them. Nothwithstanding that, the real issue is if the findings are valid. Peer review is just a first step - it essentially means that a study is fit to be published (there is more to it than that, but that will do as a lay explanation). The real validation of a study comes after it is published, when everyone - not just the peer reviewers - can check the work to see if it can be reproduced, and to check whether it is accurate. Science can be a cruel game in that regard, as I am sure most here will attest.
But - if the study proves to be valid, then the findings can be used as accepted science. Current models are verified by hindcasting - checking them against what has been known to have occurred to see if they can predict past events. Unfortunately, a LOT of models can do that, and they all contain different parameters and have different forecasts of the future. That is why the IPCC uses a range of models - because no ONE model can be said to be the only answer. As the data is refined, the models are also refined and the less accurate models fall by the wayside.
If this study is verified, it should be included as part of the model calculations. But what that actually means cannot be determined by a simple reading of the paper. The calculations would need to be incorporated, and then the models run to see what happens. That is why I - and I assume skip as well - are reserving judgement. We are a long way from knowing an outcome, and any decent scientist would hold back on forming too definite opinion until some more of these issues are resolved.
Vernon, reading that McShane and Wymer paper was indeed hard yakka, hard to stay awake that is. Given my knowledge of statistics is very limited, and some of the technical jargon requires quite some translating on my part, some thoughts:
- What's with all the political posturing at the beginning of the paper?, a major turn off for me, and a declaration of the authors motivations it would seem.
-Edward Wegman excoriated Michael Mann?, That plagiarist guy, Edward Wegman?, the same guy who claimed CO2 lagged temperature? What's that sort of junk doing in a peer reviewed paper?.
- So using the authors model they end up with virtually the same "hockey stick" shape as earlier reconstructions, but with greater uncertainty due to their choice of methodologies.
- Could it be that that is a reflection of their approach rather than the proxies themselves?
- Why do they calibrate against the Northern Hemisphere mean temperature rather than screen for proxies which reflect local temperature, such as the CSP used in Mann 2008?.
I'm working my way through it, but it seems the authors have attempted to discredit earlier reconstructions by using a tweaked approach that, not surprisingly, yields a rather different conclusion.
Vernon said:
Try here Vernon, Deep climate shows many of the flaws in this paper.
http://deepclimate.org/2010/08/19/mcshane-and-wyner-2010/
Is this journal to be taken seriously when it accepts such editorializing and political posturing? It seems that it may be vying with E & E as the most discredited so called "science journal".
Ian,
You have yet to point out where a statistician has pointed out any flaws. Please present a CV of Deep Climate that shows he is a qualified statistician. All I see in your link to his blog is that he recycled his talking point without addressing the paper at all.
And yes, Annals of Applied Statistics is one of the leading journals which publish articles in statistics. Your opinion not with standing.
I have to agree with Vernon.
AAS is ranked in the top 10 in terms of impact factor, so my guess is it does not routinely traffic in rank quackery. The question remains how the work will be received by the body of statistical expertise. This is really interesting at this point, I have to say.
But I would ask you this, Vernon: Are *you* in a position to evaluate the merits of this paper? If not, I'd advise remaining noncommittal for the nonce.
dapple/Ian
I agree with both of you about the 'political posturing' in M&W, and that is has no place in a science paper. But I also have some concerns about some of the other criticisms levelled in the Deepclimate critique. A lot of it appears - to me at least - to be 'defending the faith', and while the paper should be critiqued for any flaws in its methodology, those criticisms should also be free of any political motivation. And unfortunately, I don't think they are. Whilst the critique is right to point out the posturing in the paper, I believe it focussed to much on this and not enough on the underlying thesis of the paper - that the proxy datasets are inadequate to provide a significant reconstruction of past temperatures.
The point should be - is this a fair thesis? To be frank, all that I have read seems to suggest that M&W may have a reasonable point. I am not suggesting they are perfect or that the paper could not do with some work, but nothing I have read demonstrates that they are fundamentally off base with what they are saying.
However, and this is the big however, I go back to the point I raised in post #159. In the context of climate change and the current warming, does it matter? M&W are critiquing northern hemisphere proxy reconstructions, and there is this small issue of the southern hemisphere that has to be considered to understand global temperatures. We know there was not a temporally synchronous global MWP - all the proxy measurements from the SH do not line up with the NH (scroll up for the evidence). And no-one, not even M&W, are disputing that the instrumental record shows an unusual increase in temperatures right now. That is the real issue.
People can argue all they like about what the proxy measurements show, but even if they were able to demonstrate past global climate variability (which they haven't), to make the case that the current climate variability was just another example of this they would have to show the conditions were the same. And we all know they are not. So.... so what?
The instrumental record shows increasing GLOBAL temperature right now. The instrumental record shows an increasing level of anthropogenic CO2 in the atmosphere. We know about the link between CO2 and LWR absorption. You can carry on all you like about the accuracy of proxy data set reconstructions over the past thousand or even million years if you like. But it is a red herring. It changes nothing. Climate change is real, and we are causing it.
Skip,
I am not a statistician either. To the extent I can follow it, the arguments and methodology seems logical. I too am waiting to see what is said once this is published by other statisticians.
mandas,
your arguments that they only did the NH and the past does not matter are not logical.
a. If they are right, and we should know in a few months, then it does not matter if it is a NH proxy or a SH proxy, neither will be good enough reconstruct past temperatures to the degree needed.
b. If we do not know the past temperatures, then there is no way to determine if the current warming is outside of normal variability.
That is why this paper is fairly important and is about time the statistical community became involved.
Mandas 159,
Just a few points
I thought geology was one of a few fields related to the climate? Also they use statistical methods used in economics circles. Is this the right way to develop a 1000 year temp data set? I do not know.
(remember what i said about not everything being an affront to AGW)In regards to model verification your explanation is the way i understood it. I see it this way, if we know all there is to know about the climate then we can tweak the models to accurately hindcast and therefore we will be able to accurately predict the future.
If we do not fully understand the climate but tweak our models to match the past then there is a good chance we will not accuartely predict the future. This study or future studies like it, if verified, will show shortcommings in the models and hence our understanding of the climate. The key words here are "if verified" i accept and understand that. I suggest we now take a wait and see approach in regards to this issue, agreed?
In regards to the M&W paper i must admit when i read the preamble i thought it was something from Monkton or Watts and it does make one question the neutrality of the authors. Having said that i dont get the stats side of it so by the mere fact it has cleared peer review and will be published i must assume it has some merit. Once again only time will tell i suppose.
165,
I agree with Vernon in b, in order for us to understand the present and indeed the future we must first understand the past. If the MWP was global or merely of the Nth Hem or even just a local event then what caused it, did the LIA exist, was it global or just in Europe then what caused it. Why have temps swung up and down every 30 years or so in the 20th century?
If we dont know these things plus many others then how could we possibly predict the future with any certainty?
"The point should be - is this a fair thesis? To be frank, all that I have read seems to suggest that M&W may have a reasonable point. I am not suggesting they are perfect or that the paper could not do with some work, but nothing I have read demonstrates that they are fundamentally off base with what they are saying." - Mandas
Hmmmm, they claim that the proxies in general are too weak to detect a climate signal, then in the very next paragraph talk about the warmth of the MWP?, and that warmth would be known from?, climate proxies perhaps?. Sounds a bit off base to me, but I'm still trying to figure out the fundamental differences in their approach and that of Mann 2008, that statistical jargonese is sooooo tedious.
Vernon
".....If we do not know the past temperatures, then there is no way to determine if the current warming is outside of normal variability....."
This statement could not be more wrong. Unfortunately, it has become a mantra of many who oppose the concept of AGW that the climate has always varied, and always will. The change is just 'natural variability'.
But then, no-one denies that. Of course the climate always varies and always will. But what deniers leave of this mantra is that the climate varies in response to something happening - it does not just vary for no reason.
Climate is a complex system and is influenced by many drivers and feedback mechanisms. The sun, orbital and rotational factors, atmospheric particulates, albedo, oceanic currents, and the chemical composition of the atmosphere all play a part. We try to understand the past so we can understand the system better, but in the end when there is a change in the climate it is because something has changed to make it change.
When we look around right now, every one of these known primary influences is absent - except for one: a change in the chemical composition of the atmosphere caused by anthropogenic gas emmissions. We know this will cause the climate to change, so we can be confident with a very high level of probability that it is the culprit. And unless there is some other factor that we are not currently aware of, then we have to accept the very simple fact that the current unusual global climatic warming is as a result of GHG emmissions.
If you want to look around and find something else that is the cause, go ahead. In fact, I encourage you to do so. But until and unless you can come up with something, I am going to stick to the science we know - not the science that hasn't been discovered yet (and which may not even exist).
crakar
A few points:
"....I thought geology was one of a few fields related to the climate?..."
Not really. Geology is as close to climatology as oceanography or biology is. Paeloclimatology is the study of past climate - but it uses information from sources such as geology (and others) to reconstruct past climate.
"... Also they use statistical methods used in economics circles...."
They use statistical methods in all sciences. I use them in my studies. My point about M&M being an economist and a geologist was to highlight the fact that they are no more qualified to comment on climate than me, or skip, or dapple, or you. I am not saying they are wrong - I was making comparisons to a concern you had previously expressed about qualifications.
"..... I see it this way, if we know all there is to know about the climate then we can tweak the models to accurately hindcast and therefore we will be able to accurately predict the future...."
We will never know all there is to know about climate, and our models will never be 100% accurate. The climate is just too complex. But we will improve over time as we gather more information.
".... I suggest we now take a wait and see approach in regards to this issue, agreed?..."
If you are asking that we stop arguing about it and wait and see if the paper is accurate and what effect it may have on models, then I do agree. But if you are suggesting that we should hold off on taking any action on climate change until our models are perfect, then I do not agree, for the reason I expressed above.
The probability that the current climate change is being caused by humans is so high as to make no difference (but the answer will never be 100%). And while we can argue about the extent of future changes, the probability of further temperature increases and associated consequences if we do nothing is also so high as to make no difference.
Wouldn't be better to move off the track as soon as we see the train coming, rather than waiting until it hits us?
"If you are asking that we stop arguing about it and wait and see if the paper is accurate and what effect it may have on models, then I do agree."
Thats what i meant.
Very interesting discussion. My view on this subject is that it's impossible to measure exactly how much human beings affect the climate, and the climate is changing a lot without human beings anyway. In my opinion we should focus on stopping pollution of oceans before spending all the time on discussing whether the global warming is happening or not.
If your prime concern is the oceans, I would have thought that ocean acidification would be top of your agenda.
The only way to reverse that is to reduce CO2 concentration in the atmosphere.
Hi Ann,
Yes, it is impossible to know exactly how much we will influence the climate, but the range has been identified as somewhere close to 3oC for doubled CO2 levels with a very high degree of confidence, and the likely range extends further towards the higher side than the lower. Climate has changed alot in geological history from natural causes, but none of these causes are active right now, so it is clear that, as expected and predicted, hman influences have now overwhelmed natural ones.
I am curious as to how you feel about having a view that is directly at odds with the view of 97% of experts in this subject? Are all opinions equal when it comes to scientific questions? I tend to think not and with the exception of politically hot topics, I think most of us trust experts, especially when first, second, third and fourth opinions are all the same, and for very good reasons.
How much research and energy do you devote to a topic before you are confident that you have it right where the experts in the field have it wrong?
Thanks for the visit, and I am happy to provide some online resources if you do want to test your knowledge of the issue agaist the experts!
Ann,
"....My view on this subject is that it's impossible to measure exactly how much human beings affect the climate..."
While that's strictly true, we are affecting it to some degree.
"...the climate is changing a lot without human beings anyway...."
The climate does change for reasons other than human influence, but none of those factors are evident at the moment. Therefore, we can be very confident that the current climate changes are because of anthropogenic factors.
"... In my opinion we should focus on stopping pollution of oceans ..."
An admirable goal!
"....before spending all the time on discussing whether the global warming is happening or not..."
We shouldn't be discussing this at all. We know its happening. What we should be discussing is what to do about it. But why can't we do both - reduce both ocean pollution and anthropogenic CO2 emissions? They are not mutually exclusive, and we can multi-task.
There are too many studies to link to with strong evidence that the MWP was global and possibly the LIA as well.
Anyone who writes those studies off completely, is an alarmist in the true sense of the word.
Science works in all directions and scepticism rules in just as many directions.
No one, scientist or layman, should accept any one train of thought or evidence as read, there's a lot still to be learned about the Earth we inhabit and climate science especially, is still in it's infancy, yet to take its first baby steps.
"There are too many studies to link to with strong evidence that the MWP was global and possibly the LIA as well."
Too may? Give us one at least. Can't be too hard with so many to choose from.
"climate science especially, is still in it's infancy, yet to take its first baby steps."
Older than genetics, rocket science, several other branches of physics...
Google works for me, Chris, it isn't rocket science.
Haha. Oh my god . . .
Uh, Earth to Earthling: You can also Google the evidence that the MWP was not global.
http://en.wikipedia.org/wiki/Medieval_Warm_Period
Not that I want you relying on Wiki . . .
Dear god.
I prefer ISI Web of Knowledge:
http://apps.isiknowledge.com/summary.do?qid=2&product=UA&SID=P1nmDDiK2C…
But come on Earthling, give us your favourite paper.
Take your pick from both sides of the issue, Chris, I don't have a favourite.
http://www.google.es/search?hl=en&source=hp&q=The+medieval+warm+period+…
what you gave us is a search result; its not research.
E'ling: You haven't read any articles on this, have you?
Somewhere in this link is *my* evidence.
http://www.google.com/#sclient=psy&num=10&hl=en&q=absolute+proof+that+S…
Have fun, skip:
http://sites.google.com/site/globalwarmingquestions/mwp
And before you ask, yes, I've read them all.
Earthling, we've seen all that before. The problem is that all of those studies look at individual regions, there are no global reconstructions that indicate a pronounced MWP.
I am closing this thread and refer you and any future would be commenters to this more recent thread:
http://scienceblogs.com/illconsidered/2010/04/great_resource_on_various…
To any and all who are going to claim "countless studues" showing a MWP, please read that post and deal with its contents over there.