The Instigator
QT
Pro (for)
Losing
0 Points
The Contender
randolph7
Con (against)
Winning
6 Points

Roy Spencer's recently published study is incorrect

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Post Voting Period
The voting period for this debate has ended.
after 2 votes the winner is...
randolph7
Voting Style: Open Point System: 7 Point
Started: 8/1/2011 Category: Science
Updated: 6 years ago Status: Post Voting Period
Viewed: 1,631 times Debate No: 17735
Debate Rounds (3)
Comments (5)
Votes (2)

 

QT

Pro

Resolved: Roy Spencer's recently published study is incorrect.


Definitions:



Roy Spencer: A climatologist and a Principal Research Scientist for the University of Alabama in Huntsville

Recently published study: A research article published on July 26 which concluded as follows:

"The sensitivity of the climate system to an imposed radiative imbalance remains the largest source of uncertainty in projections of future anthropogenic climate change. Here we present further evidence that this uncertainty from an observational perspective is largely due to the masking of the radiative feedback signal by internal radiative forcing, probably due to natural cloud variations. That these internal radiative forcings exist and likely corrupt feedback diagnosis is demonstrated with lag regression analysis of satellite and coupled climate model data, interpreted with a simple forcing-feedback model. While the satellite-based metrics for the period 2000–2010 depart substantially in the direction of lower climate sensitivity from those similarly computed from coupled climate models, we find that, with traditional methods, it is not possible to accurately quantify this discrepancy in terms of the feedbacks which determine climate sensitivity. It is concluded that atmospheric feedback diagnosis of the climate system remains an unsolved problem, due primarily to the inability to distinguish between radiative forcing and radiative feedback in satellite radiative budget observations."
http://www.mdpi.com...


A non-technical summary can be found here:
http://news.yahoo.com...


Round one will be for acceptance only.
randolph7

Con

I accept your challenge.
Debate Round No. 1
QT

Pro

Dr. Roy Spencer argues that previous studies have overestimated the Earth’s climate sensitivity. He presents two main pieces of evidence to support this argument:


1) Lag regression analysis of satellite data shows that net radiative gain precedes, and radiative loss follows temperature maxima. A simple forcing-feedback model appears to show that this is the behavior expected from radiatively forced temperature changes. However, only in the case of non-radiative forcing can an accurate diagnosis of the feedback parameter be made.


2) “There is a rather large discrepancy in the time-lagged regression coefficients between the radiative signatures displayed by the real climate system in satellite data versus the climate models.”


I will demonstrate that both of these arguments are likely incorrect, and Spencer’s resulting conclusions are physically unrealistic.



Regarding Spencer’s first argument:



I agree that Spencer’s lag regression analysis “supports the interpretation that net radiative gain precedes, and radiative loss follows temperature maxima”. However, this does not necessarily imply that the temperature variations during the relative time period were radiatively forced.


The simple forcing-feedback model Spencer used to draw this conclusion was much too simple. For instance, his model did not have the ability to simulate ENSO or the hydrologic cycle.


In addition, the model was likely tuned to give the result it gave. Spencer used an ocean mixed-layer depth of only 25 meters. However, it appears that mixed-layer depths of 100–200 meters are more appropriate for simple climate models. [1] Spencer also used a lambda value of 3, much greater than the consensus value of about 1.4. [2]


Notably, Spencer made no attempt to find out how sensitive his model fits were to these different parameter values. In fact, he never presented any error bars or uncertainties in his study.


As Dr. Andrew Dessler stated, “The argument made in these papers...is extremely weak. What they do is show some data, then they show a very simple model with some free parameters that they tweak until they fit the data. They then conclude that their model is right. However, if the underlying model is wrong, then the agreement between the model and data proves nothing.” [3]



Regarding Spencer’s second argument:



Spencer claims to have demonstrated that, “There is a rather large discrepancy in the time-lagged regression coefficients between the radiative signatures displayed by the real climate system in satellite data versus the climate models.”


However, this argument does not withstand the slightest amount of scrutiny. As other scientists have pointed out, Spencer failed to account for the full range of model outputs. He compared the satellite data to only six climate models – the three most sensitive and the three least sensitive.


While these models did not match the observations well, there certainly are some that do. As Dr. Kevin Trenberth found, models which
accurately simulate ENSO tend to match the observations reasonably well. [4] This suggests that Spencer should have considered a larger number of climate models and stratified these models by their ability to simulate ENSO.


In addition, Spencer failed to account for decadal variability in the model simulations he did consider. Clearly, climate model simulations for one decade will never precisely match model simulations for another decade. This is due to factors such as random fluctuations in ocean circulation within the models.


When scientists account for the full range of model outputs as well as decadal variability, they find that Spencer's claims cannot be correct. As Dr. Trenberth concluded, “The net result is that the models agree within reasonable bounds with the observations.” [4]



The implications of Spencer’s paper are physically unrealistic:


As Spencer stated himself, “Since much of the temperature variability during 2000–2010 was due to ENSO, we conclude that ENSO-related temperature variations are partly radiatively forced. We hypothesize that changes in the coupled ocean-atmosphere circulation during the El Niño and La Niña phases of ENSO cause differing changes in cloud cover.”


However, energy budgets of the surface show that ENSO related temperature variations are not radiatively forced. [5] Therefore, Spencer’s conclusions cannot be correct.


Moreover, Spencer’s results imply that climate sensitivity is considerably lower than estimates from current climate models. However, numerous paleoclimate reconstructions do not support this. [6] Therefore, past climate changes couldn’t have occurred if climate sensitivity were as low as Dr. Roy Spencer alleges.



References:

  1. http://tinyurl.com...
  2. http://ipcc.ch...
  3. http://tinyurl.com...
  4. http://tinyurl.com...
  5. http://tinyurl.com...
  6. http://www.iac.ethz.ch...
randolph7

Con

I will demonstrate that both of Spencer’s arguments are likely correct, and Spencer’s resulting conclusions are physically realistic.



Regarding Spencer’s first argument:
Spencer’s arguments are spot on and above reproach. The simple model argument can be made for any research involving climate change. There is simply no way to ensure that all variables which impact climate change are included or to even know which ones are.

As Dr. Andrew Dessler stated, “The argument made in these papers...is extremely weak. What they do is show some data, then they show a very simple model with some free parameters that they tweak until they fit the data. They then conclude that their model is right. However, if the underlying model is wrong, then the agreement between the model and data proves nothing.”

If climate scientists have taught us anything it’s that data can and should be manipulated if it helps us reach the preferred outcome. This is simply good science a la Climategate.


Regarding Spencer’s second argument:
Spencer claims to have demonstrated that, “There is a rather large discrepancy in the time-lagged regression coefficients between the radiative signatures displayed by the real climate system in satellite data versus the climate models.”

While it may be argued that Spencer didn’t choose enough models, he certainly chose enough to reach a conclusion. Given, that no matter how airtight his argument is that it will be nit-picked over trivial matters, I fail to see how your arguments prove his wrong.

When scientists account for the full range of model outputs as well as decadal variability, they find that Spencer's claims cannot be correct. As Dr. Trenberth concluded, “The net result is that the models agree within reasonable bounds with the observations.” [4]

Decadal trends in are only weakly indicative of changes in TOA.[2] Therefore, this variability is not critical in reaching the conclusions that Dr. Spencer has put forth.


The implications of Spencer’s paper are physically unrealistic:
However, energy budgets of the surface show that ENSO related temperature variations are not radiatively forced. [5] Therefore, Spencer’s conclusions cannot be correct.

If the energy budget not radiatively forced then the debt ceiling should be heightened once again. It is because of the debt ceiling that scientists even think that the climate sensitivity is higher. If the raise the ceiling this is no longer an issue.

An 8‐yr period without upper ocean warming is not exceptional, It is explained by more radiation to space (45%) and deep ocean warming (35%) and recently‐observed changes point to an upcoming resumption of upper ocean warming[1].

Sources:

Thank you for the debate, I look forward to your reply.

Debate Round No. 2
QT

Pro


Spencer’s simple forcing-feedback model:



In the previous round, my opponent stated, “The simple model argument can be made for any research involving climate change.” However, this suggestion is downright wrong.



Dr. Spencer used zero-dimensional models in his recently published study. These models employ only one equation. While they can tell you the Earth’s average temperature, these models cannot account for any of the processes which move energy about the planet. [1]



Obviously, Spencer should have used more complex models in his study, such as four-dimensional GCMs. These models discretise and solve the full equations for mass and energy transfer and radiant exchange. Four-dimensional GCMs also contain parametrisations for processes that occur on scales too small to be resolved directly. While these models are not perfect, they account for hundreds of processes which zero-dimensional models do not. [1]



Climategate:



My opponent states, “If climate scientists have taught us anything it’s that data can and should be manipulated if it helps us reach the preferred outcome. This is simply good science a la Climategate.”



The “climategate scientists” did not manipulate data. Eight independent investigations have cleared these scientists of any wrongdoing. [2]



Spencer’s selection of climate models to evaluate:



My opponent states, “While it may be argued that Spencer didn’t choose enough models, he certainly chose enough to reach a conclusion...I fail to see how your arguments prove his wrong.”



I agree that a conclusion could possibly be drawn from only six climate models. However, for this conclusion to be accurate, the six models must represent the full range of model outputs. As I noted in the last round, some models match the observations very well but others do not.



Oddly, Spencer examined only models which did not match the satellite observations well. He then erroneously concluded that all IPCC models do not match the observations. For instance, Spencer stated, “There is a rather large discrepancy in the time-lagged regression coefficients between the radiative signatures displayed by the real climate system in satellite data versus the climate models.”



However, these conclusions do not hold true when one accounts for the full range of model outputs. As Dr. Kevin Trenberth found, “Our results suggest that there are good models and some not so good, but...the net result is that the models agree within reasonable bounds with the observations.” [3]



The implications of Spencer’s study:



In the previous round, my opponent argued, “If the energy budget not radiatively forced then the debt ceiling should be heightened once again. It is because of the debt ceiling that scientists even think that the climate sensitivity is higher. If the raise the ceiling this is no longer an issue.”



This argument is entirely nonsensical. The surface’s energy budget is purely a scientific concept. As such, it’s entirely unrelated to the debt ceiling and all other political issues. [4]



Likewise, climate sensitivity has absolutely nothing to do with the debt ceiling. Estimates of high climate sensitivity are based on scientific evidence such as paleoclimate reconstructions. [5]



References:




  1. http://en.wikipedia.org...

  2. http://www.skepticalscience.com...

  3. http://www.skepticalscience.com...

  4. http://www.cgd.ucar.edu...

  5. http://www.skepticalscience.com...

randolph7

Con

Thank you for this most provocative discussion. I’d like to thank my opponent for taking the time to explain the science where it is explainable in common terms.


Climategate:

The “climategate scientists” did not manipulate data. Eight independent investigations have cleared these scientists of any wrongdoing. [2]

I think it’s debatable whether the data was manipulated. But to say that the investigations have been independent is hardly accurate. Two of the investigations have been conducted by the Universities themselves, the so-called “The Independent Climate Change E-mails Review” had prior CRU staff on its panel[1]. Perhaps the investigations calling themselves independent are all the evidence you need but the reality is the investigations were anything but.


Spencer’s selection of climate models to evaluate:

I agree that a conclusion could possibly be drawn from only six climate models. However, for this conclusion to be accurate, the six models must represent the full range of model outputs. As I noted in the last round, some models match the observations very well but others do not.

Even if true, this doesn’t prove Spencer’s study incorrect. To be incorrect its conclusions would not logically follow from its premise. And the premise is given the models included does the uncertainty from an observational perspective is largely due to the masking of the radiative feedback signal by internal radiative forcing, probably due to natural cloud variations.

You have cited Kevin Trenbath but even he blames the data when it doesn’t show global warming:

Well I have my own article on where the heck is global warming ? We are asking that here in Boulder where we have broken records the past two days for the coldest days on record. We had 4 inches of snow. The high the last 2 days was below 30F and the normal is 69F, and it smashed the previous records for these days by 10F. The low was about 18F and also a record low, well below the previous record low…[2].


Conclusion:
My opponent may have had issues with the science in the study. But studies often conflict others in any field of science. The best one can hope for is that the peer review process will cause the researcher to go back to the table with the criticisms and try to address them. Sure there are issues raised that may need to be addressed but until they are it is too early to rule out Spencer’s hypothesis as true or false.

You’ve been a good sport, thank you for the discussion.

Sources:
[1]http://online.wsj.com...
[2]http://www.wired.com...

Debate Round No. 3
5 comments have been posted on this debate. Showing 1 through 5 records.
Posted by QT 6 years ago
QT
Sorry for the late response!
Posted by randolph7 6 years ago
randolph7
Quite alright.
Posted by QT 6 years ago
QT
I probably will not be able to post my argument today. Sorry for the change of plans.
Posted by QT 6 years ago
QT
Thanks for accepting! I plan on posting my argument tomorrow.
Posted by Gileandos 6 years ago
Gileandos
Very interesting debate.
2 votes have been placed for this debate. Showing 1 through 2 records.
Vote Placed by RoyLatham 6 years ago
RoyLatham
QTrandolph7Tied
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Reasons for voting decision: Pro has the burden to prove Spencer's study wrong. I think she cast doubt on the conclusion, but fell short of proving it wrong. The sophisticated GCMs were clearly dead wrong in predicting the last decade, so claiming that Spencer's simple models must be rejected is a weak claim. Often simple models are better.
Vote Placed by larztheloser 6 years ago
larztheloser
QTrandolph7Tied
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Reasons for voting decision: This was very close. Pro argued the methodology was bad and the conclusions wrong. The methodology, however, while bad, might not be strictly speaking "incorrect." Con was able to show that the conclusions were only a hypothesis on the available (bad) data. While late, it was enough to win. Both sides should stop telling me why the science was(n't) well-conducted and start telling me why his study was(n't) actually factually incorrect.