Global Warming Question

[Vile Atheist]

And about time, too! I will never understand why he stuck his nose into things. Talk about un-necessarily politicizing an issue!

Money, quite simply.

 

[Oberon]

Psst, btw, Oberon, I ignore almost everything you write. I established that you're a fist class bull****ter on about page two. Now I'm just batting at you for fun like a kitten with a ball of yarn.

When all else fails, there is always the ol' ad hominem.

 

[zenzero]

Friend Darkness,
Personally am as ignorant of the subject like for all subjects.
What have understood is that if there is a *WARMING* period there will also be a *COLD* period.
Everything in this universe moves in a cycle including the sun, moon, all planets, seasons etc. and everything is always evolving.
Nothing to worry about except getting rid of worries *THOUGHTS* themselves .
Love & rgds

 

[yossarian22]

You are missing the point. The latest IPCC reports use research conducted prior to 2003. 2003 is hardly out of date, even in the world of climate studies. The most current studies cite articles, books, papers, etc, prior to 2003.

Again, this has nothing to do with the validity of research against time. It has to do with the claim that disagreement with the IPCC's position in 2003 is meaningful in current context.Wikipedia lists several surveys (I dont feel that information from the wiki needs to be cited) showing a consensus, one of which is the end of last year.

Also, the survey was poorly phrased as "mainly" could be interpreted to be a plurality, majority, or supermajority so its not a very good survey to cite.

Calling your survey out of date is the only rational option considering a site like wikipedia has listed several contradictory surveys from peer reviewed sources, the latest one is from 2009. I dont really feel the need to cite this because it takes literally 5 seconds to search "climate change consensus" on wikipedia and click to the surveys.

So again, you have to show that your 2003 survey is somehow more relevant than the latest one. This is besides the point that the question asked in your survey is flawed. Something that I have pointed out at least a half dozen times.

Again, this is not a survey conducted by wikipedia. Wikipedia doesnt generate information, it collects it and (unfortunately) analyzes it. If you ignore the analysis, it is a great source.

What I am saying it that there is a clear bias in the upper echelons of the IPCC, which creates problems for trusting it.

Stop trying to draw false equivalencies. The "bias" of the IPCC shown by you is tenuous at best. The conflict of interest that comes from being funded by an oil lobby should be obvious to the clinically retarded.

No, it wasn't. The only debate in climate science with any relevancy to the survey question (the one under discussion) is whether humans are the ones mostly responsible for the current warming trend.

And you still dont understand that mostly is an extremely subjective word? Here are the 3 very common usages of it.
Plurality
Majority
Supermajority

The question was not framed as "do humans contribute more or less to climate change than natural processes" which has no room for interpretation. It was a poor survey.

 

[Oberon]

Again, this has nothing to do with the validity of research against time. It has to do with the claim that disagreement with the IPCC's position in 2003 is meaningful in current context.

I don't know why you keep talking about "the IPCC position in 2003." The survey (http://dvsun3.gkss.de/BERICHTE/GKSS_Berichte_2007/GKSS_2007_11.pdf) is not at all about this.

Wikipedia lists several surveys (I dont feel that information from the wiki needs to be cited) showing a consensus, one of which is the end of last year.

Wiki shouldn't be cited, because it shouldn't be used unless you check the sources. Here's why:


1. Did you actually read the survey from last year? The relevant qwuestion is: "Do you think human activity is a significant contributing factor in changing mean global temperatures?" 82% answered yes. However, this is pretty meaningless, nor does it contradict the results of the survey I cited, which asks instead "do you think climate change is mostly the result of anthropogenic (man-made) causes. Nearly 50% did not agree.

2. The author survey from 2004 was a review of abstracts. The author, Orestes, stated that "Not a single paper in a large-sample of peer-reviewed scientific journals between 1993 and 2003 refuted the consensus position, summarized by the National Academy of Sciences, that 'most of the observed warmin is likely to have been due to the increase in greenhouse gases concentrations." Only, this is completely meaningless. A single paper could NEVER refute a theory as complex as anthropogenic climate change. However, MANY papers cast doubt on this theory in one way or another. The entire survey was a waste

3. The other survey mentioned in wiki was rejected for publication.

Also, the survey was poorly phrased as "mainly" could be interpreted to be a plurality, majority, or supermajority so its not a very good survey to cite.

There was nothing wrong with the survey, and the question was better phrased than the 2008 survey cited by wiki

The question was "Is climate change mostly the result of anthropogenic (man-made) causes?" The respondents could then reply on a scale, from (strongly agree to strongly disagree.). 10% strongly disagreed, compared with 9% who strongly agreed. In total, 53% agreed, 13% were unsure, and 29% did not agree

Calling your survey out of date is the only rational option considering a site like wikipedia has listed several contradictory surveys from peer reviewed sources

Only they didn't. See above

,

the latest one is from 2009

No, it isn't. That was a summary on the survey of 2008 by the authors.

I dont really feel the need to cite this because it takes literally 5 seconds to search "climate change consensus" on wikipedia and click to the surveys.

You should have taken more time to check the sources.

Stop trying to draw false equivalencies. The "bias" of the IPCC shown by you is tenuous at best. The conflict of interest that comes from being funded by an oil lobby should be obvious to the clinically retarded.

1. You don't know if they were funded. A left-wing site sourcewatch.com which tries to discredit every dissenter claims that some of them were at one time or another paid by some oil company in some way.
2. Lindzen (now critic of the IPCC), who supposedly was paid in the 90s by the oil companies, was used as a lead author for the IPCC in 2001.
3. Vincent Gray (also a lead author and expert for the IPCC) has no ties to oil companies and ALSO was highly critical of their approach.
4. The IPCC is a political organization.
5. There was at LEAST one major scandal when the drafts written by the scientists themselves were edited and completely changed to promote political agendas.

The question was not framed as "do humans contribute more or less to climate change than natural processes" which has no room for interpretation. It was a poor survey.

Then so was the survey from 2008. However, I disagree, and it seems only an idiot would have trouble understanding that "mostly responsible" means more responsible than other causes.

 

[themadhair]

You really are unbelievable Oberon.

Why do you think I cite Mann’s later work and not his previous work? Might it have something to do with the fact he took into account those criticisms and showed that the same results holds? I’m genuinely trying to understand why you seem determined to attack his earlier work here rather than his later work.

Wegman was not peer reviewed – stop dancing around the issue.

Let’s have a lookie at the rest shall we? Bürger 2005 (Multiproxy Climate Reconstructions) had nothing whatsoever to do with Wegman. That paper was solely concerned with accuracy of regression extrapolations. Bürger does discuss McIntyre and McKitrick though saying the following:

The MBH98 choice of calculating the PCs of some proxy clusters from anomalies of the 20th century climate has been criticized for reducing off-calibration amplitudes and favoring hockey stick shaped results [cf. McIntyre and McKitrick, 2005a, 2005b]. Under the CNT criterion those PCs are determined from the full period to temper the impact of a strong positive 20th-century trend. We applied Preisendorfers rule N for selecting the PCs. Note that each single criterion is a priori sound, with numerous applications elsewhere, and can hardly be dismissed purely on theoretical grounds. Note further that all of the above criteria are independent, mutually consistent and can thus arbitrarily be mixed, so that any combination thereof defines one of 2^6 = 64 reasonable ‘‘flavors’’ of the regression model.

Here is Bürger’s graph of the many regression methods:

Next up we have Moberg 2005 (Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data).
The relevant graph from that paper with Moberg’s reconstruction arrowed:

Next up we have the The National Academy of Science Report from 2006 (which incorporates Moberg’s work). The relevant graph (referred to as S-1 below):

The relevant passage from that 2006 report:

After considering all of the available evidence, including the curves shown in Figure S-1 the committee has reached the following conclusions:
The instrumentally measured warming of about 0.6°C during the 20th century is also reflected in borehole temperature measurements, the retreat of glaciers, and other observational evidence, and can be simulated with climate models.
Large-scale surface temperature reconstructions yield a generally consistent picture of temperature trends during the preceding millennium, including relatively warm conditions centered around A.D. 1000 (identified by some as the “Medieval Warm Period”) and a relatively cold period (or “Little Ice Age”) centered around 1700. The existence of a Little Ice Age from roughly 1500 to 1850 is supported by a wide variety of evidence including ice cores, tree rings, borehole temperatures, glacier length records, and historical documents. Evidence for regional warmth during medieval times can be found in a diverse but more limited set of records including ice cores, tree rings, marine sediments, and historical sources from Europe and Asia, but the exact timing and duration of warm periods may have varied from region to region, and the magnitude and geographic extent of the warmth are uncertain.
It can be said with a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries. This statement is justified by the consistency of the evidence from a wide variety of geographically diverse proxies.
Less confidence can be placed in large-scale surface temperature reconstructions for the period from A.D. 900 to 1600. Presently available proxy evidence indicates that temperatures at many, but not all, individual locations were higher during the past 25 years than during any period of comparable length since A.D. 900. The uncertainties associated with reconstructing hemispheric mean or global mean temperatures from these data increase substantially backward in time through this period and are not yet fully quantified.
Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900 because of sparse data coverage and because the uncertainties associated with proxy data and the methods used to analyze and combine them are larger than during more recent time periods.

So later research backs Wegman huh? How can you claim to have honestly and objectively reviewed the relevant literature while making this claim?

I have already responded to your next three sources.

Storch et al 2004 was taken into account by NAS 2006. I have already responded to McIntyre and McKitrick. Hell check out Bürger 2007 (On the verification of climate reconstructions) if you really want the gory details of the statistics used. As I have reiterated multiple times now, the criticisms of the statistics, particularly those highlighted by NAS 2006, were incorporated into Mann’s 2007 work.

Quoting from Jensen et al (I thought you didn’t agree with IPCC work?):

The uncertainty associated with present palaeoclimate estimates of NH mean temperatures is significant, especially for the period prior to 1600 when data are scarce (Mann et al., 1999; Briffa and Osborn, 2002; Cook et al., 2004a). However, Figure 6.10 shows that the warmest period prior to the 20th century very likely occurred between 950 and 1100, but temperatures were probably between 0.1°C and 0.2°C below the 1961 to 1990 mean and significantly below the level shown by instrumental data after 1980.

The graph referred to as Fig 6.10 is as follows:

I used that fact to back the Wegman review.

So you used the fact that a graph, which wasn’t submitted for peer review until November 2007, was not present in a report, published in Feb 2007 eight months earlier, to back Wegman? Please tell you can see the problem here.

Time for to start dancing again. And I would appreciate it if you read the sources you are citing since some of them don’t support you as shown above.

 

[Renji]

I have been reading up on global warming a little, because I really know nothing about the issues and controversies surrounding it. What I learned is that during the Middle Ages, there was a period of global warming. My question is that if there was global warming before the industrial revolution, why are scientists so sure that global warming is being caused my man-made pollution rather than natural occurrences?

Global warming affects Philippines so much. In our summer season, typhoons enter the country, extreme drought destroys our crops and hail storms occur in some parts of our country knowing that Philippines is a tropical country.

 

[Alceste]

Global warming affects Philippines so much. In our summer season, typhoons enter the country, extreme drought destroys our crops and hail storms occur in some parts of our country knowing that Philippines is a tropical country.

Unfortunately, the impact of anthropogenic climate change is worst in tropical regions, most of which have little or nothing to do with causing the problem. Bad luck, getting stuck with the most serious consequences of somebody else's bad deeds. On behalf of my fellow gluttonous North Americans, I apologize.

 

[Oberon]

Might it have something to do with the fact he took into account those criticisms and showed that the same results holds?

How can you possibly make this statement? There is a reason his previous graph was called the "hockey-stick" graph. It looked like one. The more recent one still places the highest temperatures in the 20th century, but is VASTLY different from his earlier work.

I’m genuinely trying to understand why you seem determined to attack his earlier work here rather than his later work.

I'm not. I'm attacking the idea that their is a consensus among experts that the MWP was not comparable (perhaps hotter, perhaps not quite as hot, or about the same) as the current trend. Mann's later work is one argument among many that the current trend is warmer.

Wegman was not peer reviewed – stop dancing around the issue.

Are you truly this daft? Peer-review is a process for publication from academic publishers. Wegman wasn't writing a report for publication, but a review of Mann for the government. Stop building what is clearly a strawman arguemnt.

Let’s have a lookie at the rest shall we? Bürger 2005 (Multiproxy Climate Reconstructions) had nothing whatsoever to do with Wegman.

I didn't say it did. But Bürger does support Wegman's critique of Mann's earlier work, as does Moberg.

So later research backs Wegman huh?

Yes, genius. You are ignoring the fact that Wegman critiqued Mann's earlier graph. All of the above completely eradicated that.

Storch et al 2004 was taken into account by NAS 2006. I have already responded to McIntyre and McKitrick. Hell check out Bürger 2007 (On the verification of climate reconstructions) if you really want the gory details of the statistics used. As I have reiterated multiple times now, the criticisms of the statistics, particularly those highlighted by NAS 2006, were incorporated into Mann’s 2007 work.

1. Not all of them agreed with Mann's 2007
2. You asked for support for Wegman. Wegman critiqued Mann's earlier work, and every subsequent study I cited supported him.

I thought you didn’t agree with IPCC work?

Not true. What I disagree with is the upper echelon of the IPCC's blatant bias.

So you used the fact that a graph, which wasn’t submitted for peer review until November 2007, was not present in a report, published in Feb 2007 eight months earlier, to back Wegman? Please tell you can see the problem here.

What part of "wegman never critiqued Mann's later work" is so hard for you? All of the subsequent graphs completely demolished Mann's fictional hockey-stick. Now, a number of studies support the fact that the temperatures before the end of the 20th century were the highest in a thousand years or more. Of course, the graphs all end at 2000, because global average temperatures did not go up from 1998 to 2005.

Time for to start dancing again. And I would appreciate it if you read the sources you are citing since some of them don’t support you as shown above.

I read them all. You are determined to miss my points.

1. Wegman's work, while not peer-reviewed, completely demolished Mann's hockey-stick graph.
2. Subsequent studies all bore this out.
3. Most reconstructions today agree that the MWP was close to modern temperatures
4. Even if the MWP did not surpass the temp. at the end of the 20th century, the fact that it came so close prior to mass emissions of "greenhouse gasses" says something about how much of the current warming is anthropogenic.
“Sea surface temperature (SST), salinity, and flux of terrigenous material oscillated on
millennial time scales in the Pleistocene North Atlantic, but there are few records of
Holocene variability. Because of high rates of sediment accumulation, Holocene oscillations are well documented in the northern Sargasso Sea. Results from a radiocarbondated box core show that SST was -1°C cooler than today -400 years ago (the Little Ice Age) and 1 700 years ago, and 1 °C warmer than today 1000 years ago (the Medieval Warm Period). Thus, at least some of the warming since the Little Ice Age appears to be part of a natural oscillation. [emphasis added]

L. Keigwin, “The Little Ice Age and Medieval Warm Period in the Sargasso Sea” Science 274 (1996): 1503-508.

The reconstruction of global temperatures during the last millennium can provide important clues for how climate may change in the future. A recent, widely cited reconstruction leaves the impression that the 20th century warming was unique during the last millennium. It shows no hint of the Medieval Warm Period (from around 800 to 1200 A.D.) during which the Vikings colonized Greenland, suggesting that this warm event was regional rather than global. It also remains unclear why just at the dawn of the Industrial Revolution and before the emission of substantial amounts of anthropogenic greenhouse gases, Earth's temperature began to rise steeply.
Was it a coincidence? I do not think so. Rather, I suspect that the post-1860 natural warming was the most recent in a series of similar warmings spaced at roughly 1500-year intervals throughout the present interglacial, the Holocene. Bond et al. have argued, on the basis of the ratio of iron-stained to clean grains in ice-rafted debris in North Atlantic sediments, that climatic conditions have oscillated steadily over the past 100,000 years, with an average period close to 1500 years. They also find evidence for the Little Ice Age (from about 1350 to 1860). I agree with the authors that the swing from the Medieval Warm Period to the Little Ice Age was the penultimate of these oscillations and will try to make the case that the Medieval Warm Period was global rather than regional. [emphasis added]
Broecker, Wallace S. Science 23 February 2001:
Vol. 291. no. 5508, pp. 1497 - 1499
DOI: 10.1126/science.291.5508.1497

Osborn and Briffa (Reports, 10 February 2006, p. 841) identified anomalous periods of warmth or cold in the Northern Hemisphere that were synchronous across 14 temperature-sensitive proxies. However, their finding that the spatial extent of 20th-century warming is exceptional ignores the effect of proxy screening on the corresponding significance levels. After appropriate correction, the significance of the 20th-century warming anomaly disappears.



Science 29 June 2007:
Vol. 316. no. 5833, p. 1844
DOI: 10.1126/science.1140982

"The occurrence of the Medieval Warm Period (MWP) in the Southern Hemisphere is uncertain because of the paucity of well-dated, high-resolution paleo-temperature records covering the past 1,000 years. We describe a new tree-ring reconstruction of Austral summer temperatures from the South Island of New Zealand, covering the past 1,100 years. This record is the longest yet produced for New Zealand and shows clear evidence for persistent above-average temperatures within the interval commonly assigned to the MWP. Comparisons with selected temperature proxies from the Northern and Southern Hemispheres confirm that the MWP was highly variable in time and space. Regardless, the New Zealand temperature reconstruction supports the global occurrence of the MWP."

Cook, E. R., J. G. Palmer, and R. D. D'Arrigo (2002), "Evidence for a ‘Medieval Warm Period’ in a 1,100 year tree-ring reconstruction of past austral summer temperatures in New Zealand" Geophysical Research Letters, 29(14), 1667

 

[themadhair]

So I cite Mann’s later work, which incorporated the criticisms of his earlier work (and I reiterated that multiple times), and yet you still go out of your way to discredit that earlier work?

And Wegman wasn’t peer reviewed. But you still dance.

Of course, the graphs all end at 2000, because global average temperatures did not go up from 1998 to 2005.

Really? You sure you aren’t lying or being somewhat dishonest here? 2005 was the warmest year on record

1. Wegman's work, while not peer-reviewed, completely demolished Mann's hockey-stick graph.

I never once cited Mann’s earlier work. And I still can’t understand why the **** you seem intent on attacking despite the fact [SIZE=+2]I never once cited it[/SIZE].

2. Subsequent studies all bore this out.

How??? Do you even read my posts???? And, you seem to be forgetting this, [SIZE=+2]I never once cited Mann’s earlier work[/SIZE].

3. Most reconstructions today agree that the MWP was close to modern temperatures.

Good to see that you opinion has changed from the rubbish you were throwing out earlier in the thread:

THE WORLD WAS WARMER CENTURIES AGO!!!!

Given that current global temperatures are still on the up, you don’t see the problem here? Of course you don’t. But never let that stop you throwing a horde of irrelevancies out hoping to swamp what the actual research is.

4. Even if the MWP did not surpass the temp. at the end of the 20th century, the fact that it came so close prior to mass emissions of "greenhouse gasses" says something about how much of the current warming is anthropogenic.

Only if you completely ignore all the research exploring the role of humans in the problem. Which you do seem to be intent on doing.

<old studies that have been replaced with more up to date research snipped>

Fascinating. How can someone who claims to be representative of current science be so willing to quote from the old stuff?

You have already been linked to Osborn and Briffa’s response.

Have you checked out D'Arrigo et al’s 2006 work (On the long-term context for late twentieth century warming)? A quote and a graph:

Taken at face value, our reconstruction indicates that MWP conditions were nearly 0.7 C cooler than those of the late twentieth century. These results suggest how extreme recent warming has been relative to the natural fluctuations of the past millennium.
<portion snipped discusses the difficulties in this method>

Time for you dance some more.

 

[Alceste]

Fascinating. How can someone who claims to be representative of current science be so willing to quote from the old stuff?

My theory is that he's refining his technique in the hope that he can enter the incredibly lucrative field of pumping out pro-corporate pseudo-academic disinformation when he leaves school.

 

[yossarian22]

My theory is that he's refining his technique in the hope that he can enter the incredibly lucrative field of pumping out pro-corporate pseudo-academic disinformation when he leaves school.

That's a dumb route to go about it. The trick is to do genuine research and make a name for yourself then promptly sell out any sense of academic honesty.

 

[Alceste]

That's a dumb route to go about it. The trick is to do genuine research and make a name for yourself then promptly sell out any sense of academic honesty.

That's just if you want to make the big bucks - $2500 a day. There is plenty of oil money to go around for people who just have vaguely relevant-sounding degrees. If the anti-global warming propaganda racket is too hard to get a foot in the door, he could always try Intelligent Design - they'll take anybody.

 

[yossarian22]

Hey buddy, you a college graduate?

Cool, what specific school in your college.

Arts and Sciences?

$20 to sign this petition. $40 if you dont ask what it is for.

 

[Oberon]

So I cite Mann&#8217;s later work, which incorporated the criticisms of his earlier work (and I reiterated that multiple times), and yet you still go out of your way to discredit that earlier work?

I will admit that the first time you posted the link to Mann I assumed (wrongly) that you were attempting to bring out the ol' hockey-stick graph. So I attacked it without looking. I realized my mistake some time ago.

The relevant point is that all current reconstructions (including Mann) show that the MWP was comparable to the current trend. Some reconstructions show it was hotter:

The graph is from the paper cited below:

&#8220;Three warm time intervals occurred around AD 1200&#8211;1300 and 1380&#8211;1550, and from AD 1920 until the present. The warmest 10&#8211;30-yr non-overlapping periods occurred in AD 1220&#8211;1250, 1470&#8211;1500 and 1970&#8211;2000. p. 85&#8221;

J. Weckström et al. &#8220;Temperature patterns over the past eight centuries in Northern Fennoscandia inferred from sedimentary diatoms.&#8221; Quaternary Research 66 (2006) 78&#8211;86.


See also:


&#8220;Overall, the 20th century does not contain the warmest anomaly of the past millennium in most of the proxy records, which have been sampled world-wide. Past researchers implied that unusual 20th century warming means a global human impact. However, the proxies show that the 20th century is not unusually warm or extreme.&#8221; p. 104

Soon, Willie, and Sallie Baliunas. &#8220;Proxy climatic and environmental changes of the past 1000 years.&#8221; Climate Research 23 (2003) 89-110.


&#8220;According to Lamb (1997), the MWP in parts of the Arctic began at ca. AD 300&#8211;400 and came to an end ca. AD 1300, i.e., roughly synchronously with our data. Lamb (1997) estimates that during the warmest phase of the MWP at AD 1000&#8211;1200 summer temperatures in England were 0.7&#9702;&#8211;1.0&#9702;C warmer than during the 20th century, which is very close to our reconstructions.&#8221;

Seppä, Heikki, and H. J. B. Birks. &#8220;Holocene Climate Reconstructions from the Fennoscandian Tree-Line Area Based on Pollen Data from Toskaljavri.&#8221; Quaternary Research 57 (2002) 191-199.

&#8220;Finally, one unique characteristic of the 2000-year temperature variation shown in Figure 3 is that the cold-warm and warm-cold transitions are usually rapid. For example, within a period of 90 years, temperature increased by 1.3°C in the . fth and sixth centuries
(the ad 480s&#8211;500s to the 570s&#8211;590s) and decreased by 1.4°C between the thirteenth and fourteenth centuries (the 1230s&#8211; 50s to the 1320s&#8211;40s). During the mid- and late nineteenth and the early twentieth centuries (the 1860s&#8211;80s to the 1920s&#8211;40s),
temperature increased by 1.0°C within 60 years. Since the mid and late nineteenth century (the 1860s&#8211;80s) to the 1980s&#8211;90s, temperature rose by 1.5°C within 110 years, and, in particular, temperature increased by 0.5°C from1981 to 1999. It is noticeable
that, although the 0.5°C rise is not the maximum temperature change of winter half-year at a 30-year resolution over the past 2000 years, which is lower only than the 0.8°C increase between ad 1201&#8211;30 and 1231&#8211;60, such a warming rate is rather rare in warm epochs. Moreover, the 0.5°C positive departure of temperature between 1981 and 1999 was close to the warmest peak of the warm epoch over the past 2000 years. If the warming continued in the next decade, the 30-year mean temperature would be expected
to be higher than that in the thirteenth century, which was the highest recorded over the past 2000 years.&#8221;

Quanscheng Ge, et al. &#8220;Winter half-year temperature reconstructions for the middle and lower reaches of the Yellow River and Yangtze.&#8221; The Holocene 13.6 (2003) 933-40.

This study uses this approach to examine the global warming question. Two 3000-year temperature series with minimal dating error were analyzed. A total of seven time-series models were fit to the two temperature series and to an average of the two series. None of these models used 20th Century data. In all cases, a good to excellent fit was obtained. Of the seven models, six show a warming trend over the 20th Century similar in timing and magnitude to the Northern Hemisphere instrumental series. One of the models passes right through the 20th Century data. These results suggest that 20th Century warming trends are plausibly a continuation of past climate patterns. Results are not precise enough to solve the attribution problem by partitioning warming into natural versus human-induced components. However, anywhere from a major portion to all of the warming of the 20th Century could plausibly result from natural causes according to these results. Six of the models project a cooling trend (in the absence of other forcings) over the next 200 years of 0.2&#8211;1.4 &#9702;C.

Loehle, Craig. &#8220;Climate Change: detection and attribution of trends from long-term geologic data.&#8221; Ecological Modelling 171 (2004) 433-450.

Even reconstructions which do not show a warmer MWP often show the difference was very slight:

&#8220;Direct interpretation of the RCS reconstruction suggests that MWP temperatures were nearly 0.7_C cooler than in the late twentieth century, with an amplitude difference of 1.14_C from the coldest (1600&#8211;1609) to warmest (1937&#8211;1946) decades.&#8221;

Wilson, Rob, and Gordon Jacoby. &#8220;On the long-term context for the late twentieth century warming.&#8221; Journal of Geophysical Research 11 (2006)

And Wegman wasn&#8217;t peer reviewed. But you still dance.

It's not dancing. I never claimed he was peer-reviewed. It's like saying the 9/11 comission report wasn't peer-reviewed. The government asked him to go over Mann's work, he did with a panel of experts, and found the whole thing was flawed. And as it turns out, it was.

Really? You sure you aren&#8217;t lying or being somewhat dishonest here? 2005 was the warmest year on record

Not according to sattelite data:

Good to see that you opinion has changed from the rubbish you were throwing out earlier in the thread:

Wrong. As shown above, several modern reconstructions show the earth was warmer centuries ago

Given that current global temperatures are still on the up, you don&#8217;t see the problem here?

They aren't. Satellite readings have them peaking at the end of the 20th century.

Time for you dance some more.

Wrong, your turn. I gave you current research showing the MWP was as high or higher than the current trend. And, of course, now other factors contribute to temperature readings, like the UHI:

During the long geological history of the earth, there was no correlation between global temperature and atmospheric CO2 levels. Earth has been warming and cooling at highly irregular intervals and the amplitudes of temperature change were also irregular. The warming of about 0.3 _C in recent years has prompted suggestions about anthropogenic influence on the earth&#8217;s climate due to increasing human activity worldwide. However, a close examination of the earth&#8217;s temperature change suggests that the recent warming may be primarily due to urbanization and land-use change impact and not due to increased levels of CO2 and other greenhouse gases. Besides land-use change, solar variability and the sun&#8217;s brightness appear to provide a more significant forcing on earth&#8217;s climate than previously believed. Recent studies suggest solar influence as a primary driver of the earth&#8217;s climate in geological times. Even on a shorter time scale, solar irradiance and its variability may have contributed to more than sixty percent of the total warming of the 20th century. The impact of solar activity like cosmic ray flux on the earth&#8217;s cloud cover has not been fully explored and may provide an additional forcing to the earth&#8217;s mean temperature change.&#8221; p. 1581

Khandekar, M. L., T. S. Murty, and P. Chittibabu. &#8220;The Global Warming Debate: A Review of the State of Science.&#8221; Pure and Applied Geophysics 162 (2005) 1557-1586

 

[Oberon]

And even without the MWP, there were warmer times even earlier:



“Inspection of the changes in global atmospheric temperature during the last 1,000 years
shows that the global temperature dropped about 2&#9702;C over the last millennium. Thus, we live in a cooling geologic epoch and the global warming observed during the last 150 years is only a short episode in the geologic history. The current global warming is probably due to increased solar and tectonic activities. Global climate changes occur continuously and naturally at various scales of intensity, duration and direction. Geologists view these changes in context of time and intensity at scales much longer than human history (see Gerhard, 2004). Current theories of human-induced greenhouse climate change tend to ignore longer term climate history. Instead, they are focused on the results of computer models, which are predicated on the greenhouse gases being the significant driver of climate change.” P. 17

Sorokhtin, O. G., et al. “Evolution of the Earth’s Global Climate.” Energy sources, Part A 29 (2007):1-19.

“Reconstructions at both sites indicate that summer temperatures during the last interglacial were higher than at any time in the Holocene, and 5 to 10 °C higher than present. Peak Holocene temperatures occurred in the first half of the period, and have decreased since about the mid-Holocene.”

D.R. Francis et al. “Interglacial and Holocene temperature reconstructions based on midge remains in sediments of two lakes from Baffin Island, Nunavut, Arctic Canada.” Palaeogeography, Palaeoclimatology, Palaeoecology 236 (2006) 107–124


Dance.

 

[Alceste]

Wow, now Oberon is referencing his own photobucket album as an authoritative source of climate data. Amazing!

 

[Renji]

If we wanna solve the GW issue, then we should do what MJ said in his song:

I'm starting with the man in the mirror
I'm asking him to change his ways
And no message could have been any clearer
If you wanna make the world a better place
Take a look at yourself and then make a change,
gonna get it right when you got the time.....

If we just do nothing about this issue (or we just talk about it) to at least lessen this problem and its effects,then we are in great trouble.:yes:

 

[Oberon]

Wow, now Oberon is referencing his own photobucket album as an authoritative source of climate data. Amazing!

That's the only way I know how to post images. However, global temp. data from satellites can be found online from various places (the second graph of global temps, for example, lists the sources inside the picture). Feel free to check my data. As for the other graph of reconstructed tempuratures showing the MWP as warmer than today, it is from the journal article I referenced below, and can be found there.

Finally, the graphs are the least of my points. The citations say far more.

 

[Alceste]

That's the only way I know how to post images. However, global temp. data from satellites can be found online from various places (the second graph of global temps, for example, lists the sources inside the picture). Feel free to check my data. As for the other graph of reconstructed tempuratures showing the MWP as warmer than today, it is from the journal article I referenced below, and can be found there.

Finally, the graphs are the least of my points. The citations say far more.

Your dishonesty (sorry, I mean "exaggerating for rhetorical effect", as you call it) says all I need to know about your tactics and sources, thanks.