Natural global warming

[swansont]

As I said before there are several researchers who claim to show that much of the modern warming (1800-2003) is natural and also due to cyclical oscillations. If you start a new thread, I will walk you through it. If you are looking for evidence to explain the full extent of modern warming including uncertainties then I will take a pass as it would be a fools game to try to explain everything. In the new thread, please make your expectations clear so we don't get into a shouting mach over what you asked for.

 

Not sure what prevented you from clicking the "start a new topic" button yourself, but here it is

 

 

Skeptics have identified natural causes for all but 0.2-0.4 degrees of warming. Even if 100% of the unaccounted for energy rise is caused indirectly by humans, behavior change is not a particularly good idea.

 

Now: back this up.

[cypress]

Here is an article by a Dr. Roy Spencer A NASA Science Team leader for Microwave Temperature Sensing. He is a skeptic who promotes this viewpoint. I'll start here.

 

Although this particular article does not quantify the breakdown between warming that is accounted for by natural oscillations and those that are not, it presents evidence to suggest that "most" of the recent trend is natural.

 

The evidence continues to mount that the IPCC models are too sensitive, and therefore produce too much global warming. If climate sensitivity is indeed considerably less than the IPCC claims it to be, then increasing CO2 alone can not explain recent global warming. The evidence presented here suggests that most of that warming might well have been caused by cloud changes associated with a natural mode of climate variability: the Pacific Decadal Oscillation.

 

In another section of the article he provides an indicator that CO2 forcing might ultimately account for 0.44 degrees C for a doubling of CO2 concentration to 560 ppm but cautioned that the data set was too short and he was unwilling to extend this shorter term result (30 years) to a long term (100 years plus) trend . I do note that this is consistent with what he described as "most" of the warming observed since the 1800's and is consistent with the figures I provided. I will pause here for discussion.

[swansont]

He fit some parameters to a model, but I don't see where he did anything to check to see if those parameters are correct. e.g. the ocean mixing depth best fit is 800m, but is that in agreement with any experiments?

 

The best model fits had assumed ocean mixing depths around 800 meters, and feedback parameters of around 3 Watts per square meter per degree C.

(emphasis added)

 

Until there is experimental confirmation of the parameters, this does not constitute evidence.

 

 

Spencer's PDO model debunked

http://www.realclimate.org/index.php/archives/2008/05/how-to-cook-a-graph-in-three-easy-lessons/

[cypress]

If models that use assumed values don't constitute evidence (and I agree they do not) we must properly reject the AGW proponents GCM models. Where does that leave us? It is these models that provide the basis to claim CO2 warming on the order of 2-3 degrees C for a doubling in CO2 concentration to 560 ppm. Without the GCM's the IPCC has nothing to demonstrate that AGW is real.

 

First off the Dr. Spencer does not use his simple model as evidence. Here is what he says about evidence:

 

But what evidence do we have that any such cloud-induced changes in the Earth’s radiative budget are actually associated with the PDO? I address that question in the next section.

 

To see whether there is any observational evidence that the PDO has associated changes in global-average cloudiness, I used NASA Terra satellite measurements of reflected solar (shortwave, SW) and emitted infrared (longwave, LW) radiative fluxes over the global oceans from the CERES instrument during 2000-2005, and compared them to recent variations in the PDO index.

 

So if he is not using this simple model as evidence, why does he offer it? Here is what he says:

 

I used a very simple energy balance climate model, previously suggested to us by Isaac Held and Piers Forster, to investigate the possibility that the PDO could have caused some of the climate change over the last century.

 

He wanted to se if his hypothesis was on the right track before he invested a great deal of time in it. However, here are two references providing measurements indicating the 800 meter number is a reasonable value to use, thus indicating his simple model is serving his purpose.

 

Mellor, G. L., and P. A. Durbin, 1975: The structure and dynamics of the ocean surface mixed layer. Journal of Physical Oceanography.

 

Levitus, Sydney (1982), Climatological Atlas of the World Ocean, NOAA Professional Paper 13, U.S. Department of Commerce.

 

Section three contains a summary of the evidence supporting his hypothesis. He covers this evidence in much greater detail in a book that he has since had published. He makes a pitch for it on his site. So your complaint appears to be a red herring since you and your source have misidentified the purpose of his simple model and you in particular seem to have glossed over the evidence he does offer.

[Cap'n Refsmmat]

He wanted to se if his hypothesis was on the right track before he invested a great deal of time in it. However, here are two references providing measurements indicating the 800 meter number is a reasonable value to use, thus indicating his simple model is serving his purpose.

 

Mellor, G. L., and P. A. Durbin, 1975: The structure and dynamics of the ocean surface mixed layer. Journal of Physical Oceanography.

This reference does no such thing. It is available freely online:

 

http://journals.amet...OT%3E2.0.CO%3B2

 

Its figures indicate that the mixing depth is less than 100 meters. At no point in the article are depths greater than 150m or so considered.

 

Levitus, Sydney (1982), Climatological Atlas of the World Ocean, NOAA Professional Paper 13, U.S. Department of Commerce.

 

This is also available online, as a 63MB PDF:

 

ftp://ftp.nodc.noaa...._atlas_1982.pdf

 

Pages 149-150 (figures 95 and 96) shows mixed-layer depths around the world. None exceeds 500m, and most are ≤100m. There is no support for the 800m figure. In fact, the number 800m only appears in chart axes and oxygen-saturation considerations.

 

Section three contains a summary of the evidence supporting his hypothesis. He covers this evidence in much greater detail in a book that he has since had published. He makes a pitch for it on his site. So your complaint appears to be a red herring since you and your source have misidentified the purpose of his simple model and you in particular seem to have glossed over the evidence he does offer.

If the basic assumptions of the model are demonstrably wrong, its conclusions should be in severe doubt.

 

You presented the article as supporting the claim that natural oscillations can account for much of warming. As swansont's link demonstrates, it does not do so unless one uses faulty assumptions. The sources you cited demonstrate that the assumptions are indeed faulty.

 

If models that use assumed values don't constitute evidence (and I agree they do not) we must properly reject the AGW proponents GCM models. Where does that leave us? It is these models that provide the basis to claim CO2 warming on the order of 2-3 degrees C for a doubling in CO2 concentration to 560 ppm. Without the GCM's the IPCC has nothing to demonstrate that AGW is real.

What matters is if the assumptions coincide reasonably with reality.

[cypress]

I think they are in the ballpark particularly when you consider the simplicity of Spencer's model and the purpose of it. In addition, we have subsea wells in the Gulf of Mexico in depths from 300 meters to 2000 meters. We must monitor deep Ocean currents continuously to avoid issues with our pipeline risers and it is common for us to see vertical mixing well below 500 meters sometimes as far as 1100 meters. The references have the same order of magnitude but if you don't care for it, I won't attempt to support it any further. Throw out is model completely and it makes no difference since the purpose of the model is past him.

 

Why? Because it is a red herring issue. The model has no direct relationship to the evidence presented in section three. Remember his very simple and therefore likely to be not too accurate model was intended to demonstrate to him that his hypothesis was worthy of investigation. Having decided to investigate he provides a fair amount of real evidence to support his hypothesis and it stands alone independent of the model. As far as models go they can never substitute for evidence so let's stop harping on a red herring.

 

It is the evidence in section three that supports his hypothesis. Models, especially those with significant assumptions built into them do not provide evidence as Swansont indicated and I agree. His model can be completely bogus (though I suspect it has some merit) and it does not change a thing about the evidence he did present. Do you have anything against the actual evidence?

[jackson33]

Spencer's PDO model debunked[/Quote]

 

 

Part of the problem is that you have to capture not just the inputs to a dataset, but how the inputs were processed to produce the dataset, including (ideally) the algorithms, software and hardware. As an easily grasped example to illustrate this, he referred to a recent post by Ray Pierre on the RealClimate blog, How to cook a graph in three easy lessons. This post demonstrates how Roy Spencer processes inputs from two common climate datasets (the Southern Oscillation and Pacific Decadal Oscillation indexes) to get the results that support the conclusion that global warming is due to natural causes and not human activity.[/Quote]

 

http://ebiquity.umbc.edu/blogger/2008/05/

 

Basically your suggesting Ray Pierre a bloger on Real Climate, has debunked Roy Spencer*, PhD in Meteorology, Author,former NASA Scientist, oh my a AGW SKEPTIC and his research on 'Natural Trends, topping this off in 2008. Here a bit more current and overall understanding of all his current work. It's rather long, but well worth a read.

 

http://www.drroyspencer.com/

 

* http://www.drroyspencer.com/about/

 

 

I'm sorry, I can't seem to find anything on Ray Pierre, but I feel sure he is noted for something.

 

 

 

CR/cypress; While not wanting to get involved with what must be the 3,000th AGW thread I've seen, Ocean Oscillations, in my opinion have everything to do with weather patterns. Since Spencer's feels the main contributor to Natural Fluctuations in earths temperatures, which I happen to agree with (in part), are the moisture content in the atmosphere making the substantial differences in or during different periods, I'm not sure any of you are understanding the complexity of his (Spencer) theories. Where I would disagree with Spencer is the contributing factor of Ocean Oscillations, over solar effects on the atmospheres (four layers), being more important to change or holding moisture (lower levels), also involved in earths weather patterns.

 

My two cents, anyway...

[swansont]

If models that use assumed values don't constitute evidence (and I agree they do not) we must properly reject the AGW proponents GCM models. Where does that leave us? It is these models that provide the basis to claim CO2 warming on the order of 2-3 degrees C for a doubling in CO2 concentration to 560 ppm. Without the GCM's the IPCC has nothing to demonstrate that AGW is real.

 

First off the Dr. Spencer does not use his simple model as evidence. Here is what he says about evidence:

 

 

 

I didn't ask Dr. Spencer about evidence. I asked you, and this is what you offered. And now you agree it's not evidence.

 

Demonstrate that the GCMs mentioned by the IPCC did not check their models against data, and I will agree that they are also not evidence. But I don't think you can demonstrate that, since I have seen papers that do this very thing.

[cypress]

I didn't ask Dr. Spencer about evidence. I asked you, and this is what you offered. And now you agree it's not evidence.

 

Had I offered the model as evidence I would have provided Spencer's link to the model and description of it.

 

What I offered was the content and discussion of the paper as evidence. Have another look at section 3 in the paper where the evidence is presented. It shows a good match between the PDO index and radiative forcing indicating that forcing is driven by the PDO.

 

Do you have an argument against the evidence he presents regarding the observed relationship between PDO Index and Radiative forcing?

[JohnB]

Not to derail the thread, but it might be worth taking a break.

 

cypress, the main paper being used as a basis for Dr. Spencers work described in this thread is Spencer and Braswell 2008. Murphy and Foster published a "Comment on" in JoC last month and a response paper has been prepared by Spencer and Braswell. Spencer and Braswell 2010 is now in press at JGR and Dr. Spencer suggests most strongly that S&B 2010 be referenced rather than S&B 2008. S&B 2008 did have some problems correctly identified by M&F 2010 and these have been answered in S&B 2010.

 

The to and fro can be found on Dr. Spencers blog.

 

I suggest a hiatus on this topic until the latest research and results are considered.

 

There are some interesting comments on how JoC does their peer review, but that is another matter.

[swansont]

Not to derail the thread, but it might be worth taking a break.

 

cypress, the main paper being used as a basis for Dr. Spencers work described in this thread is Spencer and Braswell 2008. Murphy and Foster published a "Comment on" in JoC last month and a response paper has been prepared by Spencer and Braswell. Spencer and Braswell 2010 is now in press at JGR and Dr. Spencer suggests most strongly that S&B 2010 be referenced rather than S&B 2008. S&B 2008 did have some problems correctly identified by M&F 2010 and these have been answered in S&B 2010.

 

The to and fro can be found on Dr. Spencers blog.

 

I suggest a hiatus on this topic until the latest research and results are considered.

 

There are some interesting comments on how JoC does their peer review, but that is another matter.

 

In the context of this discussion, I think it's moot. cypress was asked to back up a specific claim, and this does not address that issue. The part of Spencer's blog post that does purport to address the issue does not constitute evidence, and this point has been conceded by cypress. So the topic of this thread has yet to be addressed.

[JohnB]

Agreed.

 

I thought it worthwhile to note that he was arguing from a paper that the author suggests shouldn't be referenced. By arguing from S&B 2008, his argument was flawed from the start.

[cypress]

In the context of this discussion, I think it's moot. cypress was asked to back up a specific claim, and this does not address that issue.

 

I tend to agree with this point. The Blog addresses a slightly different issue.

 

The part of Spencer's blog post that does purport to address the issue does not constitute evidence, and this point has been conceded by cypress.

 

Incorrect. Spencer's blog, and the paper I offered, in addition to the primary points, both include a discussion of a simple climate model developed by Spencer among other purposes to:

 

illustrate how natural monthly-to-yearly variability in global (a) cloud cover and ( b ) surface evaporation can affect our satellite observations of (1) temperature and (2) total radiative flux.

 

Spencer uses his simple climate model for purposes other than evidence, and I agree it should not and was not offered as evidence. That the model is not evidence is the where you seem to be on the same page as Spencer and me.

 

However swansont errors when he implies that the paper contains no evidence that natural events account for much of the current warming trend. Spencer describes why he developed the model and what he uses it for and then includes an excellent summary of the observable evidence that the PDO drives changes in radiative forcing which in turn change the Earth's energy budget and thus temperature. He attributes the change in forcing to natural changes in cloud cover as a result of the PDO. In other research of his and of others he references, it has been shown that very minor changes in average cloud cover (less than 2%) is more than sufficient to account for the observed temperature fluctuations over the past 200 years.

 

The evidence that natural causes accounts for much of the recently observed warming has been presented as a direct response to the topic of this thread. In addition, as a bonus, a simple climate model was included to illustrate the point more clearly but unfortunately has also provided a venue to raise red herrings.

Edited August 11, 2010 by cypress

[cypress]

Agreed.

 

I thought it worthwhile to note that he was arguing from a paper that the author suggests shouldn't be referenced. By arguing from S&B 2008, his argument was flawed from the start.

 

John, I do not believe I am referencing the S&B2008 paper. Help me better understand the connection between the the S&B2008 paper which reports on a mechanism for estimating the feedback contribution to satellite measurements of radiative flux and the the paper I linked which attributes nearly most of the recent warming trend to changes in radiative forcing presumably due to changes in cloud cover.

[pioneer]

Geological time scales are not measured in years, but over very long periods of time. Short term chatter, in long term data, is part of the average.

 

As an analogy, the earth is like a huge ship that takes a long time to make a u-turn. While the huge tanker ship is turning, the wind/waves might change and thereby alter the rate at which the turn is being made. If we look at the turn, second to second, it may appear the ships captain is changing his mind. But if we look at the longer term, the ship continued to turn, even though this short term perturbation may have appeared to the contrary. What got us all excited, was nothing but data chatter in the long term curve.

 

For example, going from the last ice age to the present, was not a day to day, or second to second, continuous temperature rise. The data has chatter, which averaged a temperature rise over a long period of time. If we target only a small sample of this long term data, we can misrepresent the turn of the good ship earth. For example, if we could find 100 years out of 1million that show a cooling trend, and use only this data, one can come to the wrong conclusion the earth was turning back to the ice age. In reality, it was only the wind shifting, as the good ship earth kept turning.

 

Out of 5 billions years of the good ship earth, we focus on the wind change of 100 years and call this the direction of the good ship earth. One is not allowed to show the longer terms trends of the last ice age, since this is not conducive to the hype. We need to focus on the wind change and infer the captain changed his mind. Fear helps this since the nature of fear is to focus the brain on the immediate present and not longer time scales.

[swansont]

Geological time scales are not measured in years, but over very long periods of time. Short term chatter, in long term data, is part of the average.

 

Which is a point that is ignored by anyone who says "warming stpped in 1998" or "it's cold today, therefore AGW is bunk"

 

 

As an analogy, the earth is like a huge ship that takes a long time to make a u-turn. While the huge tanker ship is turning, the wind/waves might change and thereby alter the rate at which the turn is being made. If we look at the turn, second to second, it may appear the ships captain is changing his mind. But if we look at the longer term, the ship continued to turn, even though this short term perturbation may have appeared to the contrary. What got us all excited, was nothing but data chatter in the long term curve.

 

For example, going from the last ice age to the present, was not a day to day, or second to second, continuous temperature rise. The data has chatter, which averaged a temperature rise over a long period of time. If we target only a small sample of this long term data, we can misrepresent the turn of the good ship earth. For example, if we could find 100 years out of 1million that show a cooling trend, and use only this data, one can come to the wrong conclusion the earth was turning back to the ice age. In reality, it was only the wind shifting, as the good ship earth kept turning.

 

Out of 5 billions years of the good ship earth, we focus on the wind change of 100 years and call this the direction of the good ship earth. One is not allowed to show the longer terms trends of the last ice age, since this is not conducive to the hype. We need to focus on the wind change and infer the captain changed his mind. Fear helps this since the nature of fear is to focus the brain on the immediate present and not longer time scales.

 

But there's a problem with this. At longer time scales climate is driven by factors that are essentially constant at shorter time scales, and further, what the temperature was a million or billion years ago is irrelevant in discussing some (many?) of the impacts, such as water level change. It's not that one is "not allowed" to show the longer trends because of "hype." Scientists who cry "foul" do so because the points are irrelevant to the discussion, and introducing them is a distraction and an example of intellectually dishonesty. Bring it up, by all means, but only do so if you can make it germane to the debate.

 

The contention is that there is enough evidence to show that what we are measuring is not simply noise.

[cypress]

In the context of this discussion, I think it's moot. cypress was asked to back up a specific claim, and this does not address that issue. The part of Spencer's blog post that does purport to address the issue does not constitute evidence, and this point has been conceded by cypress. So the topic of this thread has yet to be addressed.

 

Having reviewed the material once again and the observation that the simple climate model uses parameters that may not have been confirmed, I still note that the evidence that shows that measured changes in radiative flux and forcing correlate with and seem to be a result of natural changes in cloud cover due to the PDO. Critique of Spencer's simple climate model does not seem to detract from this evidence in any significant way unless one argues that a physical model is required to explain why the evidence is the way it is and without a valid physical model the power of the empirical evidence is reduced.

 

Is this what you are indicating?

[swansont]

Having reviewed the material once again and the observation that the simple climate model uses parameters that may not have been confirmed, I still note that the evidence that shows that measured changes in radiative flux and forcing correlate with and seem to be a result of natural changes in cloud cover due to the PDO. Critique of Spencer's simple climate model does not seem to detract from this evidence in any significant way unless one argues that a physical model is required to explain why the evidence is the way it is and without a valid physical model the power of the empirical evidence is reduced.

 

Is this what you are indicating?

 

I don't see where you've connected this with the original claim.

[cypress]

The original claim being that skeptics, of which Dr. Spencer is one, have presented evidence that indicates natural causes can account for recent observed warming. Spencer provides evidence that the PDO, a natural oscillation in ocean currents drive changes in radiative forcing. I have offered a summary of this evidence in the papers that Spencer discusses on in website and in his blog. The evidence shows good correlation between cause and effect. Thus far nobody has argued against the correlation and the evidence, though you have objected to Spencer's use of two input variables in a simple climate model where he establishes the physical basis for the observed evidence.

 

The connection seems straightforward. Please confirm that I have stated your objection correctly.

[swansont]

Spencer's model that ties the PDO to temperature relies on fitting free parameters which have not been tied to any experiments to confirm that nature agrees. He ties one parameter to another model.

[cypress]

Have I stated your objection correctly?

[swansont]

Have I stated your objection correctly?

 

No. I did, though, a couple of times.

[cypress]

My specific claim was "Skeptics have identified natural causes for all but 0.2-0.4 degrees of warming." The totality of warming since the mid 1800's is summarized here and displayed on this graphic.

 

 

Can we agree that this is the basis for the current warming trend?

[swansont]

 

Can we agree that this is the basis for the current warming trend?

 

Yes

[cypress]

Let's begin with the warming trend from the mid 20th century forward. This article by Chip Knappenberger summarizesmuch of the recent research and findings from major peer-reviewed journals to show that the amount of warming "that could potentially be from anthropogenic GHGs, or a total potential temperature rise of 0.337°C—which is 48% of the current “observed” value—or less than half of the current “observed” warming from the mid-20th century." I will offer the peer-reviewed material as we discuss each item covered.

 

Knappenberger shows the agreed basis for global temperature for this period of time, the annual HadCRUT3 global temperature record from 1950 through 2009. The trend line has value of 0.117°C/decade or temperature increase of 0.702C.

 

 

So that's the the starting point, a 0.7 degree warming trend. My task is to explain all but 0.4 of this plus the trend from 1850 through 1950.

 

From this trend the author then starts factoring in recent findings. Knappenberger said this about the first adjustment:

 

David Thompson and colleagues published a paper in Nature magazine titled “A large discontinuity in the mid-twentieth century in observed global-mean surface temperature.” In it, they documented how a change in observing practices before and after World War II produced a cold bias in the sea surface temperatures that were incorporated into the compilations of global average temperatures (see here and here for more details). Thompson et al. were unable to correct this bias (so it remains in the extant “observed” global temperature histories) but suggested that:

 

The adjustments immediately after 1945 are expected to be as large as those made to the pre-war data (~0.3°C), and smaller adjustments are likely to be required in SSTs through at least the mid-1960s, by which time the observing fleet was relatively diverse and less susceptible to changes in the data supply from a single country of origin.

 

Here is the result once the correction is made. The new trend is now .552 C

 

 

Questions, concerns?