Tuesday, August 4, 2015

Whatever happened to Dr. Mann's "hockey stick graph"?

{Sorry about the typos, I'm no professional writer.
I did polish it up a bit Tuesday evening.}

Though I don't have enough spare time for working on Ridley's folly, I needed to take the time to share this because it's both a good assessment of the state of understanding and because it underscores What A Scientist Sounds Like.  

I'm talking about Peter Sinclair's recent post featuring an excellent talk by Professor Richard Alley PhD.  
(After this intro, I repost the video along with some time signature notes for the interested student)
The Weekend Wonk: Richard Alley on Climate History and CO2 
Peter Sinclair | Weekend Wonk | August 1, 2015 
At 3:50 a graph caught my eye because it dawned on me that in a way I was basically looking at "Mann's Hockey Stick" 15 years later.  That is, after 15 years of accumulating data from all sorts of teams studying all sorts of proxies.  This graph includes additional important information, such as solar irradiance, volcanic forcing, other 'forcings' among other information.

Recall the story?  Back in the late 1990s a group of researchers lead by Michael Mann, Raymond Bradley and Malcolm Hughes were studying tree rings and glacial ice cores and using them as a proxy for establishing a paleo-temperature record for the past couple thousand years.

It was pioneering work in data processing and statistical analysis.  When finished their study, in particular their graph, was a dramatic visual wakeup call to how rapidly, if not radically, we were changing conditions on this planet.

For that Dr. Mann was viciously attacked by the Republican/libertarian PR machine as though he were the only researcher involved; and as though denying the solid evidence could make it go away.  In fact, to this day their echo-chamber continues to obsess on a couple minor flaws in those aging '98/'99 studies.

Meanwhile, the grown-ups, that is the serious scientific community, continued doing their work.  With healthy honest skepticism alive as ever, the Mann et al. papers were subjected to brutal interrogation, strong points, weak points were argued over and resolved, lessons were learned - the scientific process in action, striving to learn and improve the work going forward.  

As for Mann et al. original papers, their data, it's interpretation and graph itself have all stood the test of time, though you'd never know it listening to a Republican.


In any event, here's a look at how a decade and a half of serious study has evolved that first pioneering effort at understanding our planet's past temperature record:

 -------  Whatever happened to Mann's Hockey Stick?  -------  
Here's a look at the current state of Paleoclimate understanding
followed by an excellent short talk by Prof. Alley explaining the details.

ca. 2015


Richard Alley - 4.6 Billion Years of Earth’s Climate History: The Role of CO2

National Academy of Science member Richard Alley presents on 4.6 Billion Years of Earth’s Climate History: The Role of CO2, during the Symposium—Earths, Moons, Mars & Stars at the National Academy of Sciences 152nd Annual Meeting.
Explaining the Paleoclimate evidence in 25 minutes.

0:45  Dr. Alley says:  "I want to walk you through a little bit of our studies on the history of climate."

2:15  Range of indicators ...

3:45  "When I was a student we didn't think CO2 was all that important to Earth's history"    (He goes on to explain why that view has changed.)

3:00  A look at how the sun's variability has influenced Earth's temperature.

4:00  A look at current paleo-temperature reconstructions
along side climate models looking at past 2,000 years ending at 2000.

5:00  Meteorite changing climate?

6:00  Albedo?

6:45  Cosmic rays?

7:45  "Thing is when we walk through the factors that influence Earth's temperature - we get to CO2 and greenhouse gases fairly quickly, as a big deal."

8:00  Historic record of atmospheric gas concentrations?
800,000 though ice core evidence.
Older proxy evidence used for reconstructing temperature record.

9:15  Faint Young Sun "Paradox"

10:30  Rock-Weathering Thermostat
and greenhouse gas varieties

11:00  Rock interacting with CO2 - simple chemistry
a feedback mechanism
The lithospheric climate stabilizer
slow stabilizer.
If you have half million years to wait, no problem.

12:00  Times in ancient history when that slow lithospheric CO2 stabilizer
was overwhelm.  What happened?  Why?  When?

12:15  Three times when this slow climate stabilizer did get beat
580 MYA (Million Years Ago)
635 MYA
715 MYA

12:45  Snowball Earth - 
13:20  "There is a prediction here..."
13:40  CaCO3=CaO.CO2 - point being CO2 is a big deal in Earth's history

16:00  Considering the geologic evidence
17:30  End-Permian extinction - The Great Dying

18:20  Comparing Antarctica temperatures with atmospheric CO2 concentrations

19:00  Milankovitch's Prediction ...

19:35  "... but, there's this funny thing.  All (Earth's wobbling axis) does is move sunshine around..."

20:00  Sunshine vs. CO2 in regulating Earth's temperature... When and how CO2 is more powerful than sunshine in distributing heat around our planet.

23:00  So what?  Climate has always changed!

"The logic in that is fantastic.  It's equivalent to saying 
"Nature has always caused fires, so we don't need to worry about arson."
"We've always died, so we don't have to investigate murders."

23:30  So, where is the hope?

"...for the first time, we know how to build a sustainable energy system to power us almost forever."
We are the first generation who can look at ourselves with a straight face and say we do know how to get off this treadmill.
We do know how to build and energy system that is sustainable.

Professor Richard Alley

And then there is this:

Sunday, October 27, 2013
Enough hockey sticks for a team

One of the persistent denier myths is that the Hockey Stick (usually meaning Mann et al. 1999) has been discredited.  Not only is that myth false but Mann et al. (1999) has been validated through the publication of numerous hockey stick graphs since 1999.  Here is a brief list of the ones I know:
Mann et al. 1999, Crowley 2000, Huang, et al. 2000, Bertrand et al. 2002, Esper et al. 2002, Cronin et al. 2003, Pollack and Smerdon 2004, Esper et al. 2005, Moberg et al. 2005, Oerlemans 2005, Rutherford, et al. 2005, D'Arrigo et al. 2006, Osborn and Briffa 2006, Hegerl et al. 2007, Juckes et al. 2007, Wahl and Ammann 2007, Wilson, et al. 2007, Mann et al. 2008, Kaufman, et al. 2009, von Storch et al. 2009, Frank et al. 2010, Kellerhals et al. 2010, Ljungqvist 2010, Thibodeau et al. 2010, Tingley and Huybers 2010a, 2010b, Büntgen et al. 2011, Kemp et al. 2011, Kinnard et al. 2011, Martin-Chivelet et al. 2011, Spielhagen et al. 2011, Esper et al. 2012, Ljungqvist et al. 2012, Melvin et al. 2012, Abram et al. 2013, Marcott, et al. 2013, Rohde et al. 2013, Y Zhang et al. 2014, Shi et al. 2015.

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