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PostPosted: Tue Oct 23, 2012 12:25 am 
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"Quote:
This video actually shows the interpretation of a graph by CO2 Science in some detail:
"Why would anyone want to use proxy measurements instead of direct measurements when the direct measurements are available?"

How did your BS meter miss that? Maybe you could defend the CO2 Science interpretations since Snowy clearly gas not been willing to attempt to do so."

Wayne, I see we crossed posts.

You tactfully avoid the question. The video shows a number of different reconstructions with thermometer data pasted on the end of the reconstructions. I interpret that as more for illustrative purposes. But, please do explain, in your own words, how that has any validity in drawing the conclusion that the CWP is warmer than the MWP? You say, 'Why would anyone want to use proxy measurements if direct measurements are available?' The reconstructions start with proxy data and should end with proxy data. If we had thermometer data 1000 years ago, I'm sure we would compare it to thermometer data today. But we don't, so please explain to me why anybody would compare apples to oranges and be taken seriously? These are different data sets with different precision and granularity, but presented and interpreted as one. As a scientist, you should know better and you wouldn't accept such sloppy arguments from skeptics.

Will I have to ask you again?

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PostPosted: Tue Oct 23, 2012 2:48 am 
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http://wottsupwiththat.com/

I've kept tabs on the wattsup site for some monthes. I take everything brought up there with about 5 pounds of salt.

The wottsupwiththat grants some insight into what's going on there for those who are wondering...


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PostPosted: Tue Oct 23, 2012 2:57 am 
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Ock The question is is can we prove that globally the MWP was warmer than CWP ?

You appear to be claiming that lack of proof means that it must have been warmer during the MWP by invoking the null hypothesis.

It is probable that today is globally warmer than the MWP

http://en.wikipedia.org/wiki/Medieval_Warm_Period

Image

(dark blue 1000-1991): P.D. Jones, K.R. Briffa, T.P. Barnett, and S.F.B. Tett (1998). "High-resolution Palaeoclimatic Records for the last Millennium: Interpretation, Integration and Comparison with General Circulation Model Control-run Temperatures". The Holocene 8: 455-471. doi:10.1191/095968398667194956
(blue 1000-1980): M.E. Mann, R.S. Bradley, and M.K. Hughes (1999). "Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations". Geophysical Research Letters 26 (6): 759-762.
(light blue 1000-1965): Crowley and Lowery (2000). "Northern Hemisphere Temperature Reconstruction". Ambio 29: 51-54. Modified as published in Crowley (2000). "Causes of Climate Change Over the Past 1000 Years". Science 289: 270-277. doi:10.1126/science.289.5477.270
(lightest blue 1402-1960): K.R. Briffa, T.J. Osborn, F.H. Schweingruber, I.C. Harris, P.D. Jones, S.G. Shiyatov, S.G. and E.A. Vaganov (2001). "Low-frequency temperature variations from a northern tree-ring density network". J. Geophys. Res. 106: 2929-2941.
(light turquoise 831-1992): J. Esper, E.R. Cook, and F.H. Schweingruber (2002). "Low-Frequency Signals in Long Tree-Ring Chronologies for Reconstructing Past Temperature Variability". Science 295 (5563): 2250-2253. doi:10.1126/science.1066208.
(green 200-1980): M.E. Mann and P.D. Jones (2003). "Global Surface Temperatures over the Past Two Millennia". Geophysical Research Letters 30 (15): 1820. doi:10.1029/2003GL017814.
(yellow 200-1995): P.D. Jones and M.E. Mann (2004). "Climate Over Past Millennia". Reviews of Geophysics 42: RG2002. doi:10.1029/2003RG000143
(orange 1500-1980): S. Huang (2004). "Merging Information from Different Resources for New Insights into Climate Change in the Past and Future". Geophys. Res Lett. 31: L13205. doi:10.1029/2004GL019781
(red 1-1979): A. Moberg, D.M. Sonechkin, K. Holmgren, N.M. Datsenko and W. Karlén (2005). "Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data". nature 443: 613-617. doi:10.1038/nature03265
(dark red 1600-1990): J.H. Oerlemans (2005). "Extracting a Climate Signal from 169 Glacier Records". Science 308: 675-677. doi:10.1126/science.1107046
(black 1856-2004): Instrumental data was jointly compiled by the w:Climatic Research Unit and the UK Meteorological Office Hadley Centre. Global Annual Average data set TaveGL2v [2] was used.

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PostPosted: Tue Oct 23, 2012 11:39 am 
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Ockham wrote:
Wayne says: <Which does nothin to support the concept of GLOBALLY warmer temperatures. The key is the extent of the supposed warming. There is also nothing to support the credibility of the site you choose to quote.>

Wayne,

Alarmists and skeptics alike know the importance of the MWP to their argument. On the one hand, if the MWP can be shown to be as warm or warmer than present, then a case can be made that 20th century warming is not unprecedented and thus not unnatural. With a strong MWP, the alarmists case is weakened maybe even emasculated. It makes sense for activist scientists like Mann to do whatever he can to minimize the MWP. And that, he did, for a short while anyway, until the many flaws in his reconstructions were revealed.


But the later reconstructions by other scientists, even those who were skeptical, showed similar trends. The use of Mann's work as some series of work, which if found to be flawed in any way must result in the theory being rejected, is not very scientific at all.

Quote:
The science is now all over the map and it now so often comes down to impugning, by either side, the reputations and motives of the scientists or the people interpreting the science.


Like the recent reference to Mann?

Quote:
Which is precisely what you do in the above quote.


Really? The misrepresentation of the work of others is not generally supported as being a scientific basis.

Quote:
CO2 Science blog may have a particular bias, I grant you that, but they are a clearing house for scientific literature on the subject.


No, they are not because what they present are their interpretations of the work using doctored graphs and greatly expanded definitions in the attempt to create confusion and question just as the ultra-conservatives have been doing in the attack on evolutionary science.

Quote:
It is a great resource. That they interpret said science in one way or another is no different from the oft quoted Skeptical Science blog or RealClimate which I know to be quite unreliable even if you ignore their censorship policies.


I can see your personal bias makes no difference in this case .... (/sarcasm)

Interpretation of what is in a paper of another and modification of the data presented to imply a sought conclusion is not much of a resource. You really should watch the whole video I posted to see the way a graph from a paper was interpreted by the removal of a portion of that graph. I do not know about you but to me that is not very ethical.

Quote:
There is a second line of defense - it is to minimize the effect of a strong MWP, by making the claim (unsupported by evidence) that it was regional. By doing so, one can cast doubt as to the extent of the warming during that period. By minimizing the extent one can proclaim that the MWP warming wasn't global. Since the Southern hemisphere is mostly ocean and with very little proxy data compared to the Northern hemisphere, it stands to reason that it will take time to find answers. It begs the question as whether the Null hypothesis should be that the MWP was regional until proven otherwise or whether we assume it was global until proven otherwise. Whatever the case, with time, more and better evidence will emerge like this paper: http://www.sciencedirect.com/science/ar ... 1X12000659 pointing to a global extent of the MWP right down to Antarctica. There is a plethora of historical and archeological evidence establishing a strong MWP. The climate science is coming around. I am thankful that there are true skeptical scientists out there pointing out the malpractice in papers like Gergis et al. so that we can get at the truth faster.


Given the definititon of MWP used in the site you believe is a good resource, there will be no truth reached because it will never be shown.

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Wayne, I don't plan on sticking around here, since I don't find the information particularly revealing or the arguments very compelling. I invite you to join skeptic sites like WattsupWithThat.


Why would I waste my time doing that?


Quote:
Even though it is, by nature, a skeptic site and therefore biased as such, they don't censor (or even edit user comments like SkS does). You can reasonably be assured to make your case, as many alarmists have.


Then you do not need anyone to point out that which you do not want to believe.

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Despite our disagreement on this issue, best regards,



The same to you.
Ock

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PostPosted: Tue Oct 23, 2012 11:55 am 
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Ockham wrote:
"Quote:
This video actually shows the interpretation of a graph by CO2 Science in some detail:
"Why would anyone want to use proxy measurements instead of direct measurements when the direct measurements are available?"

How did your BS meter miss that? Maybe you could defend the CO2 Science interpretations since Snowy clearly gas not been willing to attempt to do so."

Wayne, I see we crossed posts.

You tactfully avoid the question. The video shows a number of different reconstructions with thermometer data pasted on the end of the reconstructions. I interpret that as more for illustrative purposes. But, please do explain, in your own words, how that has any validity in drawing the conclusion that the CWP is warmer than the MWP?


It actaully has more validity than stating the inverse which was the statement being supported by the CO2 Science references. If the use of proxy measurements because of the lack of direct measurements, which leaves them as the more accurate measuremnts, is supposed to be carried throughout when more accurate measurements are available the reason must not be to improve the scientific understanding but rather the personal or political position. Now, what of the actual points I was making rather than the red herring you have targeted?


Quote:
You say, 'Why would anyone want to use proxy measurements if direct measurements are available?' The reconstructions start with proxy data and should end with proxy data. If we had thermometer data 1000 years ago, I'm sure we would compare it to thermometer data today. But we don't, so please explain to me why anybody would compare apples to oranges and be taken seriously?


So the goal is not to seek the most accurate measurements, but just to support a position?

Quote:
These are different data sets with different precision and granularity, but presented and interpreted as one. As a scientist, you should know better and you wouldn't accept such sloppy arguments from skeptics.


Then the use of multiple proxy measurements should be stopped and only proxy measurements of each type compared to other measurements of that type because there are different precisions involved. In fact, the reconstructions have high error probabilities compared to direct measurement.

Quote:
Will I have to ask you again?


I do not know as you have not shown how that question relates to what I have claimed.

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PostPosted: Sat Nov 03, 2012 7:48 pm 
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Wayne Stollings wrote:
Snowy123 wrote:
Wayne Stollings wrote:
Could it be that it has to do with the "interpretations" that site presents claiming any blip in the temperature over about a thousand year span "is" the MWP somewhere. You know, those questions I posed about what the MWP is supposed to be?


a "blip" in a multi millenial proxy record is probably around a couple hundred years or so. So the MWP was significant in the papers I posted to make that "blip" in the proxy record.


Sorry, but that is pure BS. The records listed in your reference have a much higher resolution than that. Do you even read them anymore or just repeat them as if there was some basis in fact?

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By the way, a few papers came out recently that confirmed that the MWP was Global, and was warmer than the present.

Esper et al. 2012

Variability and extremes of northern Scandinavian summer temperatures over the
past two millennia


The MXD-based summer temperature reconstruction presented here sets a new standard in high-resolution palaeoclimatology. The record explains about 60% of the variance of regional temperature data, and is based on more high-precision density series than any
other previous reconstruction. Importantly, MXD sample replication prior to the Little Ice Age, during Medieval times and throughout the first millennium AD, is much better than in any other record, and we demonstrated – based on calibration trials using reduced
datasets – that these early sections of the N-Scan record likely still contain useful climate information. This persistent climate signal allowed an estimation of temperature variability throughout the Common Era, revealing warmth during Roman and Medieval times were larger in extent and longer in duration than 20th century conditions.


You have answered the question about whether you read the sources. It seems you do not or you would not claim the reconstruction of Northern Scandinavia showed anything in the global nature of the MWP. You would have realized that if you had only read the title and not even the abstract.

Quote:
Of course this study uses Tree Ring data so take it FWIW.


Tree ring data from where?

The new reconstruction is based on 578 maximum latewood density profiles from living and sub-fossil Pinus sylvestris samples from northern Sweden and Finland

Image

Christainsen and Ljungqvist 2012

In the conclusions they state:

“The level of warmth during the peak of the MWP (Medieval Warm Period) in the second half of the 10th century, equaling or slightly exceeding the mid-20th century warming, is in agreement with the results from other more recent large-scale multi-proxy temperature reconstructions.”

The extra-tropical Northern Hemisphere temperature in the last two millennia: reconstructions of low-frequency variability



The temperature reconstruction was based off of many locations in the Northern Hemisphere:

The Northern Hemisphere is now the globe .... ](*,) ](*,)


So you're saying that if the Southern Hemispheric Temperatures were added to the proxy series, the resulting temperatures would show a hockey stick like shape?

That's a pretty bold claim considering that the southern hemisphere has not warmed as much during the 20th Century as the Northern Hemisphere has. Prove it.

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PostPosted: Sat Nov 03, 2012 7:49 pm 
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By the way, the Gergis et al. paper has been retracted because of errors found within the dataset by skeptics. Kudos to McIntyre and skepticism in general.

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PostPosted: Sat Nov 03, 2012 7:50 pm 
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Wayne Stollings wrote:
Here are two such papers with the "two hundred year blip" except there are none which match.

Wayne Stollings wrote:
Two adaptations from two separate studies from the same cave in South Africa. Notice the MWP header is not consistent in the period implied. Also note the vast difference in the temperature and time period between the two. I thought the MWP was supposedly a long period of warming during a specifi time frame, not a period of peaks and valleys that moves with each graphed adaptation or interpretation.

Image

Image


I was unaware that a 2 Degree C departure from the 20th Century average is not considered to be a significant departure from the average. That's not a blip.

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PostPosted: Sat Nov 03, 2012 8:22 pm 
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Wayne Stollings wrote:
Snowy123 wrote:
Wayne Stollings wrote:
Could it be that it has to do with the "interpretations" that site presents claiming any blip in the temperature over about a thousand year span "is" the MWP somewhere. You know, those questions I posed about what the MWP is supposed to be?


a "blip" in a multi millenial proxy record is probably around a couple hundred years or so. So the MWP was significant in the papers I posted to make that "blip" in the proxy record.


Sorry, but that is pure BS. The records listed in your reference have a much higher resolution than that. Do you even read them anymore or just repeat them as if there was some basis in fact?

Quote:
By the way, a few papers came out recently that confirmed that the MWP was Global, and was warmer than the present.

Esper et al. 2012

Variability and extremes of northern Scandinavian summer temperatures over the
past two millennia


The MXD-based summer temperature reconstruction presented here sets a new standard in high-resolution palaeoclimatology. The record explains about 60% of the variance of regional temperature data, and is based on more high-precision density series than any
other previous reconstruction. Importantly, MXD sample replication prior to the Little Ice Age, during Medieval times and throughout the first millennium AD, is much better than in any other record, and we demonstrated – based on calibration trials using reduced
datasets – that these early sections of the N-Scan record likely still contain useful climate information. This persistent climate signal allowed an estimation of temperature variability throughout the Common Era, revealing warmth during Roman and Medieval times were larger in extent and longer in duration than 20th century conditions.


You have answered the question about whether you read the sources. It seems you do not or you would not claim the reconstruction of Northern Scandinavia showed anything in the global nature of the MWP. You would have realized that if you had only read the title and not even the abstract.

Quote:
Of course this study uses Tree Ring data so take it FWIW.


Tree ring data from where?

The new reconstruction is based on 578 maximum latewood density profiles from living and sub-fossil Pinus sylvestris samples from northern Sweden and Finland

Image

Christainsen and Ljungqvist 2012

In the conclusions they state:

“The level of warmth during the peak of the MWP (Medieval Warm Period) in the second half of the 10th century, equaling or slightly exceeding the mid-20th century warming, is in agreement with the results from other more recent large-scale multi-proxy temperature reconstructions.”

The extra-tropical Northern Hemisphere temperature in the last two millennia: reconstructions of low-frequency variability



The temperature reconstruction was based off of many locations in the Northern Hemisphere:

The Northern Hemisphere is now the globe .... ](*,) ](*,)


Snowy123 wrote:
So you're saying that if the Southern Hemispheric Temperatures were added to the proxy series, the resulting temperatures would show a hockey stick like shape?

That's a pretty bold claim considering that the southern hemisphere has not warmed as much during the 20th Century as the Northern Hemisphere has. Prove it.


No, I said earlier that adding the measured temperature to any of the proxy reconstructions will give you a hockey stick .... just as every one of them have done to date.

In this post, you quoted, I am pointing out your mistakes in stating the MWP was global based on the NH reconstructions referenced. I had thought making that portion larger and making it bold would help, but it seems not.

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PostPosted: Sat Nov 03, 2012 8:26 pm 
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Snowy123 wrote:
Wayne Stollings wrote:
Here are two such papers with the "two hundred year blip" except there are none which match.

Wayne Stollings wrote:
Two adaptations from two separate studies from the same cave in South Africa. Notice the MWP header is not consistent in the period implied. Also note the vast difference in the temperature and time period between the two. I thought the MWP was supposedly a long period of warming during a specifi time frame, not a period of peaks and valleys that moves with each graphed adaptation or interpretation.

Image

Image


I was unaware that a 2 Degree C departure from the 20th Century average is not considered to be a significant departure from the average. That's not a blip.


It is when it is a very short term increase instead of the hundreds of years normally associated with the WMP in the NH records and when the level of increase, duration, or starting points are not shown in both graphs. Notice the blips do not line up with each other, show similar temperatures, or durations even though they are by the same people from the same location? Talk about data error issues, this is a big one.

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PostPosted: Sun Nov 04, 2012 9:59 am 
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Wayne Stollings wrote:

No, I said earlier that adding the measured temperature to any of the proxy reconstructions will give you a hockey stick .... just as every one of them have done to date.

In this post, you quoted, I am pointing out your mistakes in stating the MWP was global based on the NH reconstructions referenced. I had thought making that portion larger and making it bold would help, but it seems not.


That's not correct as the Christainsen and Ljungqvist paper came to a very opposite conclusion than the conclusion a researcher would come to if the proxy record looked like a hockey stick. The yellow is obseved temperatures, and they still are not warmer than the MWP.

A Hemisphere is pretty darn close to getting a sample of what the Global temperature was like during this timeframe, don't you agree? It is highly unlikely that something radically different was taking place in the Southern Hemisphere during the MWP and the CWP.

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Last edited by Snowy123 on Sun Nov 04, 2012 10:12 am, edited 1 time in total.

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PostPosted: Sun Nov 04, 2012 10:02 am 
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I disagree that the data doesn't line up with each other. The MWP is showing up at around 1000 AD on one of your charts, wheras on another it has shown up from 1050 AD-1300 AD. Assuming that there is room for error with these proxies (which there always is) then they don't disagree with each other as much as you claim they do.

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PostPosted: Sun Nov 04, 2012 1:23 pm 
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Snowy123 wrote:
By the way, the Gergis et al. paper has been retracted because of errors found within the dataset by skeptics. Kudos to McIntyre and skepticism in general.

Then why do you bother with this thread, except to attempt legitimacy to your denialist rhetoric. [-X [-( =; :mrgreen:

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PostPosted: Sun Nov 04, 2012 2:34 pm 
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Snowy123 wrote:
Wayne Stollings wrote:

No, I said earlier that adding the measured temperature to any of the proxy reconstructions will give you a hockey stick .... just as every one of them have done to date.

In this post, you quoted, I am pointing out your mistakes in stating the MWP was global based on the NH reconstructions referenced. I had thought making that portion larger and making it bold would help, but it seems not.


That's not correct as the Christainsen and Ljungqvist paper came to a very opposite conclusion than the conclusion a researcher would come to if the proxy record looked like a hockey stick. The yellow is obseved temperatures, and they still are not warmer than the MWP.


It is very correct as Christainsen and Ljungquist is but one paper compared to many and even a reconstruction with a significant MWP will not show the rapid increase of the modern era, which is what makes the blade of the hockey stick.

Quote:
A Hemisphere is pretty darn close to getting a sample of what the Global temperature was like during this timeframe, don't you agree?


No, it is not. It is by definition only half IF you get a good coverage, which is not available.

Quote:
It is highly unlikely that something radically different was taking place in the Southern Hemisphere during the MWP and the CWP.


To go with your request. Prove it. The temperature measurements do not support this hypothesis.

Image

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PostPosted: Sun Nov 04, 2012 2:48 pm 
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http://www.clim-past.net/8/765/2012/cp-8-765-2012.pdf

The corresponding
95% confidence intervals have widths of 0.6 (two millennia
long reconstruction) and 0.4 C (500-yr long reconstruction)
for 50-yr smoothed values, thereby showing
that the residual noise-variance is relatively small compared
to the reconstructed low-frequency signal.
Our main conclusions are as follows.
– Our reconstructions indicate – in agreement with the
results of Moberg et al. (2005); Ljungqvist (2010), and
Loehle and McCulloch (2008) – that the first millennium
AD was generally significantly warmer than the
second millennium AD. The 17th century was the coldest
century during the last two millennia and most of
the LIA seems to have been colder than during the Dark
Age Cold Period ca. 300–800 AD. In general, our LOC
reconstructions show larger low-frequency variability
than previous reconstructions.
– Our two-millennia long reconstruction has a well defined
peak in the period 950–1050AD with a maximum
temperature anomaly of 0.6 C. The timing of
the peak of the MWP in our reconstruction is in agreement
with the reconstructions of Esper et al. (2002a)
and Ljungqvist (2010). The reconstructions of
Mann et al. (2008, 2009) show a longer peak warming
covering the whole period 950–1100 AD, and the reconstruction
of Moberg et al. (2005) shows a somewhat
later as well as longer peak MWP warming than in the
present paper. The level of warmth during the peak
of the MWP in the second half of the 10th century,
equalling or slightly exceeding the mid-20th century
warming, is in agreement with the results from other
more recent large-scale multi-proxy temperature reconstructions
by Moberg et al. (2005), Mann et al. (2008,
2009), Ljungqvist (2010), and Ljungqvist et al. (2012).

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