Global Warming: Man or Myth?

Scientists can also wear their citizen hats

Shooting the Messenger with Blanks

with 16 comments

As detailed in previous blog posts (Wegman-gate: Alert Congress & the Media and Science by Error and Trial), and by this recent Washington Post letter from Rep. Joe Barton (R-TX), Dr. Michael E. Mann is once again being questioned (attacked) about his paleoclimatology research.  I thought it might be constructive to see how Dr. Mann’s published work stacks up against other, more recent temperature reconstructions.

Date: 1999
Authors: Mann, Bradley, Hughes
Methodology: Principal Components Analysis (PCA) - Northern Hemisphere
Plot:

MBH99 graph as shown in the 2001 IPCC report
MBH99 graph as shown in the 2001 IPCC report

Summary: Hockey stick shape.  Warmer Medieval Warm Period (MWP) followed by cooler Little Ice Age (LIA) and significantly warmer temperatures in the modern era.

Controversy: This is the plot that gets all of the attention.  This is the plot that the National Research Council (NRC) investigated in 2006 at the request of Congress.  The NRC supported the scientists and their conclusions.  This is the plot that the Wegman Report has criticized as being severely flawed.  This is the plot that Virginia Attorney General Ken Cuccinelli claims may have been the result of nefarious activity on the part of Dr. Mann while he was at University of Virginia.  And this is the chart that Rep. Joe Barton claims “that Mr. Mann’s global warming projections were rooted in fundamental errors of methodology that had been cemented in place as “consensus” by a closed network of friends.”

DO THE CLAIMS OF BARTON, WEGMAN, AND CUCCINELLI STAND UP?
SINCE 1999, HAS MANN’S WORK BEEN VERIFIED BY OTHERS?


Date: 2008
Authors: Mann, Zhang, Hughes, Bradley, Miller, Rutherford, Ni
Methodology: Composite plus scale (CPS) in orange color and RegEM-based EIV estimation in black color – Northern Hemisphere
Plot:

  

Mann et al. (2008) temperature reconstruction.

Mann et al. (2008) temperature reconstruction.

Summary: Using two differing methodologies (CPS & EIV), and whether tree rings were included or not, the plot has a hockey stick shape.  Warmer MWP followed by cooler LIA and significantly warmer temperatures in the modern era.
 


Date: 2008
Authors: Huang, Pollack, Shen
Methodology: Direct temperature measurement from boreholes – Global
Plot:

Direct T measurement from boreholes

Direct T measurement from boreholes

Summary: A broad cool minimum around AD 200 that was followed by a warming that peaked AD 1200–1400 (MWP); a subsequent cooling to a minimum around AD 1700–1800 (LIA); followed by rapid and substantial warming. None of the borehole reconstructions show MWP peak temperatures as high as late 20th century temperatures.”


Date: 2009
Authors: Kaufman, Schneider, McKay, Ammann, Bradley, Briffa, Miller, Otto-Bliesner, Overpeck, Vinther, Abbott, Axford, Bird, Birks, Bjune, Briner, Cook, Chipman,Francus, Gajewski, Geirsdóttir, Hu, Kutchko, Lamoureux, Loso, MacDonald, Peros, Porinchu, Schiff, Seppä, Thomas
Methodology: Composite plus scale (CPS) – Northern Hemisphere above 60o N latitude
Plot:

Kaufmann et al. (2009)

Kaufmann et al. (2009)

Kaufmann et al. modified by University Corporation for Atmospheric Research

Kaufmann et al. modified by University Corporation for Atmospheric Research

Summary: Hockey stick.  A pervasive cooling in progress 2000 years ago continued through the Middle Ages and into the Little Ice Age. The cooling trend was reversed during the 20th century, with four of the five warmest decades of our 2000-year-long reconstruction occurring between 1950 and 2000.”


Date: 2010
Authors: Thibodeau, de Vernal, Marcel, Mucci
Methodology: Isotopic analysis (oxygen isotopes) of shells recovered from sediments of North Atlantic Ocean
Plot:

Thibodeau et al. (2010) T plot. The grey lines to the left of the graph are ignored due to disturbance by the coring process.

Thibodeau et al. (2010) T plot. The grey lines to the left of the graph are ignored due to disturbance by the coring process.

Summary:  Hockey stick.  “…it is unquestionable that the last century has been marked there by a warming trend having no equivalent over the last millennium.”


Date: 2010
Author: Ljungqvist
Methodology: Composite plus scale (CPS) - Northern Hemisphere extra-tropics (90–30°N)
Plot:

Ljungqvist T reconstruction (Source: Skeptical Science)

Ljungqvist T reconstruction (Source: Skeptical Science)

 

Summary: Hockey stick.  “Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods, except for the period c. ad 300–800, despite significant differences in both data coverage and methodology.”  “The temperature of the last two decades, however, is possibly higher than during any previous time in the past two millennia…”


DR. MANN’S WORK HAS BEEN VERIFIED BY MANY OTHER SCIENTISTS

The hockey stick-shape temperature plot that shows modern climate considerably warmer than past climate has been verified by many scientists using different methodologies (PCA, CPS, EIV, isotopic analysis, & direct T measurements).

To believe Rep. Joe Barton and Attorney General Ken Cuccinelli one must also believe in magic.  Consider the odds that various international scientists using quite different data and quite different data analysis techniques can all be wrong in the same way.  What are the odds that a hockey stick is always the shape of the wrong answer?

The only reasonable conclusion is that Barton and Cuccinelli are
shooting the messenger with blanks.

It is time for you two gentleman to do some constructive work.


Update (10/17/2010): Science committee responds to Rep. Joe Barton - Dr. Gerald North corrects Barton’s mistakes.  North was Chair of the National Research Council’s Committee on Reconstruction of Surface Temperatures for the Last 2000 Years, mandated by Congress in 2006.

About these ads

Written by Scott Mandia

October 15, 2010 at 8:03 am

Posted in Uncategorized

16 Responses

Subscribe to comments with RSS.

  1. Good collection of charts!

    John Mashey

    October 15, 2010 at 7:56 pm

  2. It is time that action was taken against Cuccinelli for abuse of his position in pursuit of a personal campaign against science that conflicts with his ideology.

    Where does the US constitution stand on abuse of power in this way?

    TrueSceptic

    October 16, 2010 at 5:05 pm

  3. Scott, wonderful work! Succinct and solid with excellent reasoning. My favorite line: “What are the odds that a hockey stick is always the shape of the wrong answer?”

    The Hockey Stick argument is getting gray in it’s old age. Denialists just keep trying to dye it so it looks like a fresh young issue.

    I added your post to the link section on the OSS Hockey Stick page:

    http://www.ossfoundation.us/projects/environment/global-warming/myths/the-hockey-stick

    I also did a piece on Cuccinelli in this months Leading Edge report:

    http://www.ossfoundation.us/projects/environment/global-warming/summary-docs/leading-edge/2010/oct-the-leading-edge

    Consider adding the OSS Foundation site to your blogroll?

    Also, I finally broke down and did a blog site at

    http://www.johnreisman.com/

    My latest item is on economics in case you or anyone wants to add to the discussion?

    http://www.johnreisman.com/2010/10/balancing-economies/

  4. apart from the fact that if you remove the UHI induced readings from the end of the hockey stick you see that its been warmer in the past than the present, the fact is the work at UV was done using tax payers money so the taxpayer owns it and should be able to view it when ever they want and if manns work is so good what is there to hide.

    Mandia: UHI-induced? Microclimates? Not true.

    john wilson

    January 7, 2011 at 2:04 pm

    • Who is hiding anything? Most climate data, particularly that of the more recent, more accurate time periods, is freely available. It’s your fault for simply not looking or not asking how to obtain it.

      W Scott Lincoln

      January 21, 2011 at 7:17 pm

  5. [...] is has been addressed in my blog post titled: Shooting the Messenger with Blanks where I showed that the hockey stick-shape temperature plot that shows modern climate [...]

  6. [...] Dr. Mann’s work has been verified by many other international scientists.  The hockey stick-shape temperature plot that shows modern climate considerably warmer than past climate has been shown by many scientists using different methodologies (PCA, CPS, EIV, isotopic analysis, & direct T measurements). [...]

  7. If it is so well verified, then that is more reason for other scientists to drop the invalid Mann charts with poor methodology.

    MikeN

    March 20, 2011 at 8:02 pm

  8. My post got posted before I could finish.

    You show Mann 2008, well both the CPS and EIV as used in that paper have flaws. It is very easy to throw out all the science on this page, because one of your charts (Mann et al 2008 CPS) uses data upside down. Basic error that remains uncorrected even after pointed out. Given that scientists are not willing to throw out that error, then why shouldn’t I assume the other charts are equally flawed?

    MikeN

    March 20, 2011 at 8:04 pm

    • LOL! You’re a funny one, MikeN. If you’re so concerned about Tiljander, you should know that Kaufmann used it in the same direction as Tiljander (you know, he did the correction you claim remains uncorrected).

      It is my concentation that even acknowledging an error would not change your mind, it would just strengthen your idea that everything is wrong. Just see how you paint all work with the same brush.

      Marco

      March 21, 2011 at 1:54 am

  9. Individual proxies do *not* support the hockey stick result of Kaufman et al. above:

    http://bobtisdale.wordpress.com/2009/12/17/a-look-at-the-individual-proxies-used-in-kaufman-et-al-2009/

    Keith “One Tree” Briffa is an author on the paper for good reason: it relies on a SINGLE proxy for the hockey stick shape, with the rest of the 23 added in just to create the illusion of a hockey stick over a larger area of the planet and to smooth out the noise. That single proxy is the same old Yamal proxy which does *not* represent the overall region, and which itself relies on a single tree for its shape. Local T records in that area do not show this same shape, so it is *not* a good T proxy (http://wattsupwiththat.com/2009/10/30/yamal-treering-proxy-temperature-reconstructions-dont-match-local-thermometer-records/).

    Mandia: Please read the post again. You missed the forest because of the tree.

    NikFromNYC

    July 11, 2011 at 7:31 am

    • Shorter NikFromNYC: The Kaufmann paper relies on a single proxy. Plus 23 proxies. Therefore it relies on a single proxy.

      Nik, before writing down something, you need to use your brains to understand what you’re writing.

      – frank

  10. [...] no surprise to those that respect science and have actually looked at the data.  As I showed in Shooting the Messenger with Blanks, the hockey stick-shaped temperature reconstruction that shows modern climate considerably warmer [...]

  11. [...] The Messenger With Blanks. Here’s an entry from the blog, “Global Warming. Man or Myth?” “As detailed in previous blog posts (Wegman-gate: Alert Congress & [...]

  12. [...] 2010-10: ProfMandia – Shooting the Messenger with Blanks [...]


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Follow

Get every new post delivered to your Inbox.

Join 2,835 other followers

%d bloggers like this: