How can skeptics give credence to Spencer’s various blog articles when they contradict each other?
Roy Spencer recently claimed that global warming is caused by chaotic variations in cloud cover associated with the Pacific Decadal Oscillation. To test this hypothesis, he fit the output of a simple climate model, driven by the PDO, to temperature data from 1900 through 2000. Spencer did obtain a somewhat reasonable fit, but only by using an ocean mixed-layer depth of 800 meters. http://www.drroyspencer.com/research-articles/global-warming-as-a-natural-response/
Several scientists have pointed out that this value is physically unrealistic. Oddly, Spencer himself seems to agree. As he stated in another blog post, “The model’s response to these radiative forcings depends upon how I set the model’s ocean mixing depth, which will determine how much the temperature will change for a given energy imbalance imposed upon the model. I found that a 70 meter deep layer provided about the right RATIO between the satellite-observed monthly radiative variations and SST variations.” http://www.drroyspencer.com/2011/01/update-further-evidence-of-low-climate-sensitivity-from-nasas-aqua-satellite/
However, if Spencer had used a mixed-layer depth of 70 meters in his original analysis, he would have found that the PDO could account for only a small portion of the observed global warming trend. http://www.realclimate.org/index.php/archives/2008/05/how-to-cook-a-graph-in-three-easy-lessons/ http://www.skepticalscience.com/Roy-Spencers-Great-Blunder-Part-3.html
Despite this rather obvious fact, Spencer still maintains that the Pacific Decadal Oscillation is the main cause of the current global warming as well as historic climate changes.
How can Spencer continue to make these claims given his admission that the mixed-layer is only 70 meters deep? Moreover, how can other skeptics give credence to Spencer’s various theories when they contradict each other?
2011-07-11T18:22:36Z
@ Larry: Even Spencer and Lindzen acknowledge that the Earth is warming.
Dana19812011-07-12T17:06:10Z
Favorite Answer
Thanks Baccheus. I do try to understand the denialist theories because unlike them, I really am a skeptic. If PDO can explain global warming, I want to know about it.
The problem is that it can't. As QT notes, in order to blame global warming on PDO, Spencer is forced to choose physically unrealistic parameter values in his overly simplistic climate model - and yes, Spencer relies entirely on models to support his hypothesis.
Dr. Barry Bickmore, who has pointed out the errors in Spencer's modelling, noticed the exact same contradiction as this question notes:
"in my recent review of his book, The Great Global Warming Blunder, I pointed out another serious abuse of the same simple climate model he used in his latest blog post. One of the problems I pointed out was that his model assumed a 700 m mixed layer in the ocean, when it is really something more like 100 m. In other words, his model assumed that the entire top 700 m of the ocean heats up and cools down at the same rate, which is nonsense....in the blog post I’m critiquing here, I found the following frank admissions that I was right." http://www.skepticalscience.com/roy-spencers-latest-silver-bullet.html
I hate to say it, but Roy Spencer is a denier. He consistently tweaks the parameters in his models to make them fit the conclusions he wants to believe. Deniers are constantly claiming that "warmists" fudge the data - well that's not true, but Roy Spencer does. And let's not forget that Spencer recently admitted he feels his job is political, not scientific:
"I view my job a little like a legislator, supported by the taxpayer, to protect the interests of the taxpayer and to minimize the role of government." http://answers.yahoo.com/question/index;_ylt=ArMXaR_xHxwTVO1DQY5K06Psy6IX;_ylv=3?qid=20110706154733AAQuovg
Can you imagine the furor from deniers if James Hansen had said he thinks his job is to expand the role of government? Yet deniers seem to have no problem with Spencer believing his job is to minimize the role of government.
Deniers are not skeptics, and Spencer is a denier.
Here the odd thing: The deniers here don't even read Spencer. They are just flat out unread and uneducated.
In the past couple of years at least twice people have asked for a plausible natural explanation for the observed warming. Of all the dimwitted boobs that regularly appear here to make uneducated rants, not not one, not one single one of them could answer. The good answers came from the real scientists who sometimes answer here -- Trevor, Pegminor, Dana. These folks are the only ones who could provide insight into the contrarian theories even though they don't believe those theories. The best explanations of Spencer's theories, other they your own here, have been posted by Dana.
It is clearly evident that the deniers in this forum are only angry old men who resent people with education. You do not get any scientific information from these ranters.
Why then do you give credence to an unproven theory that are be back by models which can't replicate history? Mr Spencer and Mr Watts are doing some scientific studies as opposed to those sillies at East Anglia, Mann and Hanson.
Since this question will be deleted if you put it to a vote and "no best answer" is chosen over Larry's answer, I will do my best to answer this question. Roy Spencer beliefs about climate seem to be based on wishful thinking. He seems to be hoping to discover something that other scientists have missed. Of course, if Spencer ever makes such a discovery, he may as well book a flight to Stockholm to collect his Nobel Prize.
edit
If James Hansen had exaggerated something, like Roy Spencer did by exaggerating mixed-layer depth, denialists would be calling for his head.