EnviroLink Forum

"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?

Ock

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"...To hunt means to have the land around you like clothing" Barry Lopez

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...

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



(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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Pollution is not the solution

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.



Like the recent reference to Mann?



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



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.



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.



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.



Why would I waste my time doing that?




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




The same to you.
Ock

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With friends like Guido, you will not have enemies for long.

“Intellect is invisible to the man who has none”
Arthur Schopenhauer

"The difference between genius and stupidity is that genius has its limits."
Albert Einstein

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?




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



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.



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

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With friends like Guido, you will not have enemies for long.

“Intellect is invisible to the man who has none”
Arthur Schopenhauer

"The difference between genius and stupidity is that genius has its limits."
Albert Einstein

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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~Snowy123; Amateur Meteorologist and Climatologist.

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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~Snowy123; Amateur Meteorologist and Climatologist.

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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~Snowy123; Amateur Meteorologist and Climatologist.

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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With friends like Guido, you will not have enemies for long.

“Intellect is invisible to the man who has none”
Arthur Schopenhauer

"The difference between genius and stupidity is that genius has its limits."
Albert Einstein

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.

_________________
With friends like Guido, you will not have enemies for long.

“Intellect is invisible to the man who has none”
Arthur Schopenhauer

"The difference between genius and stupidity is that genius has its limits."
Albert Einstein

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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~Snowy123; Amateur Meteorologist and Climatologist.

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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~Snowy123; Amateur Meteorologist and Climatologist.

Then why do you bother with this thread, except to attempt legitimacy to your denialist rhetoric.

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"With every decision, think seven generations ahead of the consequences of your actions" Ute rule of life.
“We do not inherit the earth from our ancestors; we borrow it from our children”
― Chief Seattle

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.



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



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

_________________
With friends like Guido, you will not have enemies for long.

“Intellect is invisible to the man who has none”
Arthur Schopenhauer

"The difference between genius and stupidity is that genius has its limits."
Albert Einstein

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).

_________________
With friends like Guido, you will not have enemies for long.

“Intellect is invisible to the man who has none”
Arthur Schopenhauer

"The difference between genius and stupidity is that genius has its limits."
Albert Einstein