Another climate "truth" debunked?

Question

Anyone at all educated about AGW remembers the Mann hockey stick study. By studying tree ring growth (no room for error there) this study tried to show a drastic current warming trend by minimizing the Medieval warm period and the Little Ice Age. This study was completely debunked by some real scientists. They found that even random data entered into Mann's model created a hockey stick. Yes, that's right, a computer model was "programed" to return a hockey stick shape.

http://www.worldclimatereport.com/index.php/2008/02/11/a-2000-year-global-temperature-record

Now, a new study using 18 different proxy data from around the world (not localized to the European nations) has confirmed the truth we once understood. Yes, there was global wide warmer temps in the Medieval Period (funny it has been referred to as the Climate Optimum for years), and yes, The Little Ice Age was actually quite cold.

http://www.worldclimatereport.com/index.php/2008/02/11/a-2000-year-global-temperature-record

Answer 1

The conclusion of the paper was,

"the MWP peak remains 0.07°C above the end of the 20th-century values, though the difference is not significant."

Some observations:

- The scientist himself concludes that "the difference is not significant," so why would a skeptic misrepresent it as significant?

- The study averaged 29 years of 20th century temperatures to represent it, so the latest data point compared with the MWP is 1992.  Who in their right mind would claim that 1992 is a proxy for current temperatures?  At best he has shown that the temperatures were arguably close 15+ years ago.

- The earth has warmed a lot since 1992.  Averaging in the previous 14 years distorts the data downward and therefore skews (biases) the study and waters down the argument.

- The study used only 18 points around the globe.  A couple of days ago skeptics complained that several thousand was an insufficient record to show global warming, now 18 is sufficient to disprove it?  To make a point at all they need to have their cake and eat it too.

- The study mixes all different types of temperature estimation available, but selectively discards tree ring records.  Anyone can argue just about anything if you selectively cherry pick only the data that agrees with your conclusion.

- Are those different types of historical estimates really comparable to each other?

- Are they really accurate to .07 degrees?  Pollen counts in ice cores are accurate and adequate as temperature measurements, to an accuracy of 7 hundredths of a degree?  The author says not.

- The study doesn't seem to explain any supposed mechanisms invloved.  

The skeptics representing this study as showing something say "it was warmer during the Medieval Warm Period!"  So what?  I've never seen a skeptic explain what mechanism caused that, so they can claim to have proven something about the causes or trajectory of current global warming, or whether or not it's anthropogenic.

As the author puts it, "It must be emphasized, of course, that this result is based on limited data."

The author's actual conclusion, corrected in 2008 with the help of skeptic poster child Steve McIntyre (an energy exploration industry insider who apparently claims he is not involved in the oil industry) is:

"The main significance of the results here is not the details of every wiggle, which are probably not reliable, but the overall picture of the 2000 year pattern showing the MWP and LIA timing and curve shapes. Future studies need to acquire more and better data to refine this picture."

In other words, according to the author the Medieval Warm Period and the Little Ice Age do seem to show up in the types of records he looked at.  Did we really need a scientific study to tell us that?  No, we already knew that one was warm and the other was cold.  

Kudos to the author though if he gets his funding for "Future studies... to acquire more and better data to refine this picture."

So what can we deduce that his future studies will be?

One of Loehle's previous papers is:

"Geologic Methane as a Source for Post-Glacial CO2 Increases: The Hydrocarbon Pump Hypothesis," C. Loehle (Environ. Res. Div., Argonne Nat. Lab., Argonne IL 60439), Geophys. Res. Lett., 20(14), 1415-1418, July 23, 1993.

"Using a simple dynamic model, the hydrocarbon pump, evaluates the hypothesis that historical CO2 levels could have been governed by releases of methane from clathrates and as natural gas. This is likely; confirming evidence is presented."

So his interest in confirming past temperatures appears to be related to his hypothesis that these sorts of warmings in the past may be related to natural methane releases... which can cause significant subsequent greenhouse gas warming.  

Add man's greenhouse gasses to that, as we have for the past 150 years, and we're simply reinforcing the earth's demonstrated tendency to warm in response to increased greenhouse gasses.  Let's hope Loehle gets his funding to further study it.

Answer 2

The re have been natural warming and cooling periods in the past. So what. None of tha thas anything to do with CURRENT global warming--or the fact taht its caused by human action.

The re have been natural warming and cooling periods in the

Answer 3

THEY CHERRY PICK THERE DATA.

try looking at the chart for the last 65 million years.

http://www.globalwarmingart.com/wiki/Ima...

it shows we have about 6 more degrees to go just to get out of the ice age we are in.

the hockey stick has been going the other way for the last 3 million years.

all it is doing is finely leveling off

Answer 4

You need to learn how to do what we here in academia call, "evaluating the credibility of a source"

because when you cite  unreliable sources you only make yourself look unintelligent

I suggest you browse these:

http://mason.gmu.edu/~montecin/eval-sour...

http://mason.gmu.edu/~montecin/web-eval-...

Answer 5

Are you freaking kidding me?

Not only is this an old story, but you're lying about the scientist's results.  He did not find that the MWP was warmer than today.  He found that the MWP was warmer than 1935, and essentially the same temperature as the end of the 20th century.

http://answers.yahoo.com/question/index;...

Plus his study (which was actually a metastudy) was extremely oversimplified and flawed, which is why he had to publish it in Energy&Environment.

"Energy and Environment, a journal geared mainly to social scientists.  The journal's editor, Sonja Boehmer-Christiansen, a reader in geography at the University of Hull, in England, says she sometimes publishes scientific papers challenging the view that global warming is a problem, because that position is often stifled in other outlets. "I'm following my political agenda -- a bit, anyway," she says. "But isn't that the right of the editor?"

Answer 6

Dana is partly correct.  There were some errors in his original study.  But this is a new study that corrected all of the errors.  It is also a study that used any proxy temperature reconstructions other than tree rings.

http://icecap.us/index.php/go/joes-blog/...

Answer 7

I really don't see anything debunked. I see you posting an article from some online site, not yet peer reviewed, that you post here as proof, because it fits your beliefs. That's called jumping the gun.

People like Dr. Craig Loehle are like consultants coming into a company to fire people to get a better bottom line. They don't really know how anything in the business they are trying to "streamline" works, but they do know they have to get rid of so may people to please Wall Street.

EDIT - and worldclimatereport.com got the article from Energy and Environment website. If I'm going to publish an article for peer review, I would publish it in an ISI listed peer review journal, otherwise it looks like a back-door way of spitting data to the public to feign relevance.

http://www.sourcewatch.org/index.php?t*t...