The small number of credible skeptics out there (e.g., Spencer, Lindzen) have spent much of the last decade searching for a negative feedback in our climate system. If a sufficiently big one is found, then it would suggest that warming over the next century may well be small.
Most climate scientists, however, are reasonably certain that a negative feedback big enough to overwhelm the well-known positive feedbacks in the climate system, such as the water vapor feedback [PDF], does not exist. Why?
Negative feedbacks tend to dampen out climate change. If you add greenhouse gases to the atmosphere or the sun brightens, then the hypothetical negative feedback will counteract the warming, leaving the climate nearly unchanged. While it may be comforting to believe that a negative feedback exists, it is extremely difficult to reconcile the existence of a big negative feedback with our past observations of climate variability.
For example, the ice ages rely on a carbon dioxide feedback to provide their large amplitude. If there were a big negative feedback in the system, then how do you explain the large swings in to and out of ice ages? No way that I know of.
Similarly, the Paleocene Eocene Thermal Maximum is also thought to be the result of a huge release of greenhouse gases. With a large negative feedback in the system, how do you explain the rapid temperature rise during that event?
Finally, how do you explain the warming of the last few decades if the climate is intrinsically stable?
Climate skeptics, of course, don’t have to look at all the data. In one thread, they can argue “it’s the sun,” while in another thread they can argue “there is a negative feedback.” The problem is that these are mutually contradictory. Any negative feedback working on carbon dioxide would also work on increased solar forcing. One cannot argue both that our present-day warming is due the sun, and that there is a negative feedback that prevents carbon dioxide from warming and climate.
If you look at all the data, the simplest explanation is that there is no negative feedback, and we are experiencing warming due to increases in greenhouse gas concentrations. There is, in fact, no fully consistent, alternative theory.
Comments
View as Flat
Delay And Deny Posted 10:59 am
21 Jan 2009
What's really laughable about all this is that you assume that the Earth is here for the sole purpose of keeping a cozy temperature well suited to humans. Nothing could be further from the truth! What seems like "extreme changes" are paltry compared to the history of this climate. Even the temperature swings from summer to winter dwarf "climate change" by an order of magnitude!
So, when you say, "there is no feedback mechanism", I mean, gee, so it rose 1 degree in a century. Does your thermostat go off every time it gets slightly more chilly? Nope -- otherwise you'd hear a click every second.
So, first of all, of course there must be some feedback mechanism, or the temperature would be violently oscillating. It doesn't. Therefore there is. It's simply that, like ultraviolet light, we don't have the eyes with which to see it.
If you want a good discussion about dampening:
http://you-read-it-here-first.com/viewtopic.php?t=3507&am ...
You are now living in the Hansen Economy!
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Robco1 Posted 12:10 pm
21 Jan 2009
Nice logic...
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lgcarey Posted 2:33 am
22 Jan 2009
Regards.
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Sam Wells Posted 3:11 am
22 Jan 2009
In certain ways, black soot fallout onto arctic snow and ice can lead to rapid melting. In other ways, the brown clouds can obscure the sun and make it cooler.
Perhaps I'm talking parts of the globe instead of the whole thing, but perhaps you could help me understand this better.
Interestingly, or at least to myself, is the recent cold snap in the Northeast, which makes perfect sense to me as being consistent with Global Warming (as opposed to being a skeptic). We've come a long way in understanding global climatological impacts when we can understand that average global warming can cause local cooling!
sam
Onward through the fog
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Andrew Dessler Posted 3:57 am
22 Jan 2009
In the original version of the post, I had the word "forcing" in the title, but have changed it to "feedback."
Now, on to your question. Aerosols are a forcing of the climate, because they directly change the radiative balance of the planet. A feedback is a process that responds to an initial warming, and either reinforces (positive) or ameliorates (negative) the initial warming. Sorry for the confusion.
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GonzoDon Posted 4:22 am
22 Jan 2009
Well, no, jabailo, what I assume is that the Earth is here for the sole purpose of this generation, and possibly the next one, to extract as much fossil fuel from the earth as we physically can, as quickly as we can, so that we can continue to drive gas-guzzlers from our sprawling suburban McMansions to the nearest WalMart, consuming as much cheap plastic crap and corn-syrup-spiked cola as we please.
I think all of the above is promised, somewhere, in The Bible.
Too bad about the future generations.
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Black Wallaby Posted 10:28 am
22 Jan 2009
In your latest work on water vapour with Zhang and Yang you show a positive ~2 W/m^2, but I seem to recall Spencer suggests higher negative values than that somewhere. (= Good news)
The IPCC, Graeme L Stephens, and others, have described how extremely difficult it is to understand the complexity of clouds in their formation, structure and what they do WRT to climate.
And, then there is this, with abstract quoted:
On the twilight zone between clouds and aerosols (GRL)
Koren, Remer, Kaufman, Rudich and Martins
http://climate.gsfc.nasa.gov/publications/fulltext/koren_ ...
Cloud and aerosols interact and form a complex system leading to high uncertainty in understanding climate change. To simplify this non-linear system it is customary to distinguish between "cloudy" and "cloud-free" areas and measure them separately. However, we find that clouds are surrounded by a "twilight zone" - a belt of forming and evaporating cloud fragments and hydrated aerosols extending tens of kilometers from the clouds into the so-called cloud-free zone. The gradual transition from cloudy to dry atmosphere is proportional to the aerosol loading, suggesting an additional aerosol effect on the composition and radiation fluxes of the atmosphere. Using AERONET data, we find that the measured aerosol optical depth is higher by 13% ± 2% in the visible and 22% ± 2% in the NIR in measurements taken near clouds relative to its value in the measurements taken before or after, and that 30%−60% of the free atmosphere is affected by this phenomenon.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Come-on Andrew, admit it...... The jury will probably be out for a very long time on clouds, (and aerosols), and I don't understand how you can make such important assumptions as you have above!
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manacker Posted 10:31 am
22 Jan 2009
You apparently didn't read Spencer's study showing a strong net negative feedback from clouds, based on actual physical observations (rather than just climate model assumptions).
Or the independent study by Norris, showing essentially the same.
These two studies cleared up IPCC's "largest source of uncertainty", i.e. "cloud feedbacks", as well as Ramanathan's earlier uncertainty whether or not cloud feedbacks are positive or negative.
Don't just stick your head in the sand, Andrew, and hide behind paleoclimate gobbledygook when there are real-time, real-life data out there.
Makes you look like a "climate denier".
Regards,
Max
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Des Emery Posted 12:27 pm
22 Jan 2009
Pre-Columbian indigenous natives in the Americas were hunters and farmers, the latter clearing and re-clearing large tracts of land to grow various crops. Following Columbus, the European explorers and conquerors brought metal tools, blankets and beads with them for trade. They also brought epidemics of typhus, cholera, smallpox and other diseases which decimated the natives. Hunters survived, farmers didn't.
When the farmers deserted their lands, the jungles and forests surged back, and drew enough CO2 out of the atmosphere to produce a cooling effect over the whole globe, leading to the Little Ice Age anomaly. The settlement of the New World after that released a lot of carbon, warming the climate again. The advent of the Industrial Age contributed even more carbon, and we are now seeing the results of that connection.
There is therefore evidence that what we do does indeed change the way in which the atmosphere is balanced, and the change leads to either warming or cooling depending on the amount of carbon which gets sequestered or released by our actions.
So it all comes down to our choice whether we acknowledge it or not.
Des Emery
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Black Wallaby Posted 9:15 pm
22 Jan 2009
According to Wikipedia:
It is thought that up to 100 million indigenous people may have lived in the Americas when the 1492 voyage of Christopher Columbus began a historical period of large-scale European interaction with the Americas.
Today, according to Wikipedia, the population of the Americas is ~941 million, or about ten times greater. (or the American pre Columbians were about 1.5% of today's total world population, which is arguably more efficient at forest clearing)
What you are saying is that this ancient relatively tiny population of peoples, without metal tools, or bulldozers and stuff to clear forests, like we have today, were able to create the "Little Ice Age" (LIA)?
(BTW: This is despite that Mann et al "proved" with their "hockey-stick" that the LIA never existed anyway.)
Please elaborate on your story.
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Black Wallaby Posted 9:56 pm
22 Jan 2009
Now I'm up again, to say scratch it!
Don't change the subject!
Concentrate on the issues that Andrew Dessler raised.
You really are quite naughty Des!
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314159265 Posted 11:08 pm
22 Jan 2009
http://tamino.wordpress.com/2009/01/19/a-bag-of-hammers/
"...and it means absolutely nothing except that Spencer really doesn't understand what he's doing."
Mars J. Pictor Florifulgurator, Western Bavarian Forest.
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amazingdrx Posted 11:28 pm
22 Jan 2009
The problem with planetary thermostatic climate control, for our comfort, is that it is generally catastrophic.
Bring it on! Let nature do her terror. It's just another chance for gaaawd to show his grace. He can start over, reset the life force with some armageddon.
Like you restart your brain after a dream, or restart your computer after it rains.
Is reality really the mark you want to set? Or would you rather be on his side?
http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin
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kmp Posted 1:15 am
23 Jan 2009
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Black Wallaby Posted 9:04 am
23 Jan 2009
Tamino, a handsome prince who is lost in a distant land, is pursued by a serpent. He faints from fatigue and three ladies, attendants of the queen appear and kill the serpent... ...[later]the three ladies [re]appear and punish his lie by paying for his birds with a stone instead of food, water instead of wine and placing a padlock over his mouth.
From synopsis; Mozart's The Magic Flute
Oh, and BTW, Try this: http://www.climateaudit.org/?p=2897
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Black Wallaby Posted 3:08 pm
23 Jan 2009
Putting aside the difficulties in defining what is the "average global temperature"#, using the absolute Kelvin temperature scale, the average global T commonly stated is 288K. (~15C) Of this, 33 degrees is commonly presented as the Greenhouse effect. It seems that YOU are arguing that if we are say 1 degree "too hot" right now, the normal range prior to the Miocene (23 million years ago), was maybe 277 - 287K, or crudely speaking, a thermal variation of about 3.5%. In biological terms that would indeed be very severe WRT food supplies etc, if it occurred with today's large and widespread population, but in physical terms, it is actually quite a small variation
However, within the most recent 23 million years, embracing the Miocene epoch,(which is quite a long time ago), it is reported@ that the T variation is only 6 degrees C, or crudely, in absolute thermal terms, is a variation of only ~2.1%
Now here is an extract from Wikipedia on the more recent Pliestocene, an epoch going back 1.8 million years, which is quite a long time ago:
Pleistocene climate was characterized by repeated glacial cycles where continental glaciers pushed to the 40th parallel in some places. It is estimated that, at maximum glacial extent, 30% of the Earth's surface was covered by ice.
The T variation of the Pliestocene together with the Holocene through to today appears to be@ about 4 degrees or crudely ~1.4% thermally in the last 1.8 million years.
Note that the ice age on the transition into the early Holocene did not result in extinction of modern humans, although the Neanderthals that appear to have been more genetically adapted to the cold did paradoxically disappear, maybe as a consequence of competition/superior technology from ex African Homo Sapiens.
If you are complaining that Spencer's "thermostat" has only been thermally accurate to within ~1.4 % in the last 1.8 million years, you should perhaps consider the low frequency planetary etc cycles$, which are historically more significant than the CO2 "Hot Armageddon" hypothesis that you and others prefer!
#E.G. http://www.sciencedaily.com/releases/2007/03/070315101129 ...
@E.G. Ref Climate history: http://www.scotese.com/climate.htm
$ E.G. Milankovitch, for a start
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manacker Posted 5:57 pm
23 Jan 2009
You quote Tamino (whodat?) to refute Spencer?
Get serious.
Spencer is a respected and renowned climate scientist.
Tamino is either a prince in a Mozart opera who pranced through the forest with a magic flute trying to save a kidnapped princess or the anonymous jerk who still believes in the validity of the since discredited Mann boondoggle and sends out unsubstantiated alarmist climate misinformation.
The "strongly positive" cloud feed back as assumed by all the climate models cited by IPCC (leading to 1.3C of the 3.2C warming assumed by IPCC for 2xCO2) has been effectively refuted by the study of Spencer et al., which showed that the cloud feedback on warming is strongly negative instead.
The Spencer et al.study was also validated by a totally independent study by Norris, also showing a strongly negative feedback from clouds.
Stick with the scientists and forget the "prancing princes".
Max.
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manacker Posted 6:04 pm
23 Jan 2009
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manacker Posted 8:51 am
24 Jan 2009
In your 22 January post to Andrew Dessler, you wrote, "In your latest work on water vapour with Zhang and Yang you show a positive ~2 W/m^2, but I seem to recall Spencer suggests higher negative values than that somewhere.
Yeah. That is correct. Actually much higher. Check the Spencer study on physically observed cloud feedback:
http://blog.acton.org/uploads/Spencer_07GRL.pdf
"Our measured sensitivity of total (SW + LW) cloud radiative forcing to tropospheric temperature is -6.1 W/m^2K".
The IPCC estimates on 2xCO2 climate sensitivity of 3.2°C includes net positive feedbacks from both water vapor and clouds, as well as a negative feedback from lapse rate and a positive feedback from surface albedo.
In its AR4 WG1 Chapter 8 report (p.630) IPCC states that the multi-model mean forcing and standard deviation for each in W/m^2 °C is:
Water vapor +1.80 ±0.18
Lapse rate -0.84 ±0.26
Albedo +0.26 ± 0.08
Clouds +0.69 ± 0.38
Using these feedback parameters, the 2xCO2 feedback temperature response would be:
+0.8°C [2xCO2] (p.758)
+1.5°C [Water Vapor]
-0.8°C [Lapse Rate]
+1.5°C [Sub-total 1] (p.631)
+0.4°C [Albedo]
+1.9°C [Sub-total 2] (p.633)
+1.3°C [Clouds]
+3.2°C [Total, all feedbacks] (p.633)
If we now correct the IPCC assumed strongly positive net feedback from clouds with the physically observed strongly negative feedback as demonstrated by Spencer et al., (and even if we add in the slightly higher latest Dessler et al. estimate for water vapor), this will result in a total net 2xCO2 climate sensitivity of around 0.6 to 0.8°C, rather than the IPCC assumed value of 3.2°C.
Hope this helps.
Regards,
Max
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Black Wallaby Posted 8:58 am
24 Jan 2009
Concerning the possible ID of Tamino, and his bad habit of banning some posters that try to make inconvenient scientific observations. Here are some comments starting at post #40
Jean S (40), March 20th, 2008
... could you (I'm banned there) ask your master to illustrate (mathematically) the following "conclusion", which is rather central to the "pro-NC-PCA stance in Tamino's last post"...
Hu McCulloch (56):
"Open Mind" regular "Dhogaza" repeatedly refers to Tamino as "HB," which would seem to rule out Grant Foster. Why do Mosh and others think he or she is Foster?
steven mosher (60):
re 56. We figured it out a while back. Then to test the assumption I posted posts to RC with
the name Grant Foster. Something innocuous like, "great post gavin" it was blocked.
I did the same thing at Tamino's site and at Eli's site. All blocked.
I changed my IP and tried again, this time putting hints in the text like " i GRANT you this will FOSTER some lively conversation...." blocked.
So, that confirmed it for me. not 100% but hey...
Kim (118):
He's quit posting my comments, now, too. Apparently Tamino's tired of me 'witnessing my faith' in the ironic words of Hank Roberts. There is a new term for skeptics; now we can be called sun-worshippers.
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Black Wallaby Posted 9:19 pm
24 Jan 2009
I see my last post crossed yours by a few minutes, and I now belatedly see your good news.
In Andrew's lead article, he opens with the quote below, so it would be interesting to see if he comments on Spencer's work on clouds.
The small number of credible skeptics out there (e.g., Spencer, Lindzen) have spent much of the last decade searching for a negative feedback in our climate system. If a sufficiently big one is found, then it would suggest that warming over the next century may well be small.
It is fairly late here, and there are a couple of things in Spencer's paper that make me wonder how "global" the negative 6.1 w/m^2 is, and.... K means 2x CO2 sensitivity, derived from temperature anomaly? I've only had a quick look, but perhaps Andrew can explain it to us better. I see he responded to Sam Wells with his #5, thus:
In the original version of the post, I had the word "forcing" in the title, but have changed it to "feedback."
Now, on to your question. Aerosols are a forcing of the climate, because they directly change the radiative balance of the planet. A feedback is a process that responds to an initial warming, and either reinforces (positive) or ameliorates (negative) the initial warming. Sorry for the confusion.
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manacker Posted 5:25 am
25 Jan 2009
You wrote: "there are a couple of things in Spencer's paper that make me wonder how "global" the negative 6.1 W/m^2°C [forcing] is".
It's true that Spencer's observations only covered the tropics from -20 to +20 degrees latitude.
This region comprises around 40% of the earth's surface area and receives well over half of the total insolation.
The crux of the matter is that IPCC AR4 WG1 Chapter 8 (p.630) lists an assumed multi-model mean forcing for clouds as +0.69±0.38 W/m^2°C.
On p.633 IPCC informs us that this forcing from clouds would result in an increase of the 2xCO2 climate sensitivity of +1.3°C (from + 1.9°C without clouds to +3.2°C with clouds).
So if Spencer's negative forcing from clouds is globally only half (or even one-fourth) the -6.1 W/m^2°C observed over the study area, this still represents a major negative feedback from clouds, that would essentially cancel out the net positive feedbacks from water vapor less lapse rate plus surface albedo, as listed by IPCC.
It is the physically observed "major negative feedback" that Andrew Dessler relegates to the "Easter Bunny".
Regards,
Max
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manacker Posted 6:25 am
25 Jan 2009
The "cloud feedback" story has an interesting background, as I'm sure Andrew will agree.
There have always been conflicting hypotheses as to the real impact of clouds on AGW. While it is clear that the net overall impact of clouds on our climate is one of significant cooling (several times the assumed greenhouse warming impact from CO2), it has been unclear what would happen to clouds with increased surface warming caused by AGW.
High altitude ice-crystal clouds allow incoming SW radiation to pass through but effectively trap reflected outgoing LW radiation, thereby leading to warming.
Lower altitude liquid droplet clouds reflect incoming SW radiation, thereby leading to cooling.
A study by Lindzen suggested that the net effect of higher surface temperatures would be to reduce the formation of (warming) high altitude ice-crystal clouds, thereby providing a net negative feedback. Lindzen called this postulated (but unproven) effect "the infrared iris".
In a study on the radiative forcing of water vapor and clouds, Ramanathan stated:
"The few results we have on the role of cloud feedback in climate change is mostly from GCMs. Their treatment of clouds is so rudimentary that we need an observational basis to check the model conclusions. We do not know how the net forcing of -18W/m^2 will change in response to global warming. Thus, the magnitude as well as the sign of the cloud feedback is uncertain."
The climate models cited by IPCC all assumed a strongly positive (warming) net feedback from clouds (resulting in 1.3°C of the assumed total 2xCO2 climate sensitivity of 3.2°C), although IPCC conceded in its 2007 SPM report "Cloud feedbacks remain the largest source of uncertainty."
So it should have come as a great relief to all in the scientific community when this "largest source of uncertainty" was cleared up by the physical observations of Spencer et al., providing "an observational basis to check the model conclusions", as Ramanathan had lamented was lacking earlier.
And not only that! The physical observations of Spencer et al. demonstrated that the net feedback from clouds with warming is a strongly negative feedback, not only canceling out the IPCC-assumed +1.3°C warming effect from clouds, but resulting in an even larger cooling effect, so that the 2xCO2 climate sensitivity would now be an innocuous 0.6 to 0.8°C, rather than the alarming 3.2°C, as estimated by the GCMs cited by IPCC.
Rejoice! The end is not near!
But instead of sighs of relief, we heard howls of indignation and anguish by the "climate science community". How could Spencer publish something that shoots down the very notion of alarming AGW? How could the physically observed facts be so different from the hypothesis? What was wrong with Spencer's observations, which had to be incorrect as they conflicted with the theory, which had to be right.
And finally (the most ridiculous and transparent reaction of all): let's ignore (or deny) the physical observations and make a flat statement (based on paleoclimate data [?!] and other gobbledygook) that negative feedbacks are as real as the "Easter Bunny".
Sorry, Andrew. In the court of common sense, you LOSE.
Max
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314159265 Posted 10:06 pm
25 Jan 2009
(See http://www.desmogblog.com/node/1397 for his other affiliations)
On filtering trolls like the infamous kim: This is a necessity if you want to keep the blog readable and keep thread lengths reasonable. Some bloggers and readers like actual scientific discussion, not textual garbage.
Mars J. Pictor Florifulgurator, Western Bavarian Forest.
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314159265 Posted 10:37 pm
25 Jan 2009
http://tamino.wordpress.com/2008/07/28/spencers-folly/
It's about his "Feedback vs. Chaotic Radiative Forcing: "Smoking Gun" Evidence for an Insensitive Climate System".
Tamino thinks that Spencer actually believes his stuff.
Looks like one of the finest cases to study the psychopathology of denial.
Much better than the garbled pseudo-maths of "Black Knight" Monckton.
Mars J. Pictor Florifulgurator, Western Bavarian Forest.
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manacker Posted 5:18 am
26 Jan 2009
Sorry 314159265, sounds like you are a bit confused. Tamino's so-called "debunking of Spencer" is full of glaring errors and omissions.
"Warmer air holds more water vapor" is basically a correct statement, but it should be reworded, more accurately, to "warmer air can hold more water vapor". IPCC assumes that is does so to maintain constant relative humidity. Physical observations have shown that this assumption is incorrect and that the IPCC assumptions on positive feedback from water vapor are therefore exaggerated.
"As earth warms there's less ice and snow covering the planet" (leading to a positive surface albedo feedback). Great theory, but it just hasn't worked out that way in real life. After a year of low snow cover in 2007 (not quite as low as it was throughout most of the 1980s and 1990s, however) December 2008 Northern Hemisphere snow cover is back above the 1978-2008 average. The December linear trend since 1978 has been an increase of 0.838 million sq.km. (around 2%) per decade..
http://climate.rutgers.edu/snowcover/chart_vis.php?ui_yea ...
Arctic sea ice extent has receded (with lots of media hype); Antarctic sea ice extent has grown (with no media coverage). The latest data from NSIDC show that the global extent is about the same today (December 2008) as it was over the 1979-2000 mean baseline:
December 2008
12.53 sq. km. (Arctic)
12.20 sq. km. (Antarctic)
24.73 sq. km. (Total)
1979-2000 mean
13.40 sq. km. (Arctic)
11.08 sq. km. (Antarctic)
23.48 sq. km. (Total)
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135
According to IPCC, "lapse rate" feedback is negative, reducing the impact of the closely related positive water vapor feedback, not a positive feedback, as falsely assumed by Tamino.
But Tamino's biggest error is that he does not discuss the observed strongly negative feedback from clouds. This physically observed negative feedback is so strong that it, in effect, cancels out all the other assumed positive feedbacks combined. Instead of contributing +1.3C to the 2xCO2 climate sensitivity as assumed by IPCC, the physically observed feedback from clouds represents a cooling impact of around -1.5C. This puts the total 2xCO2 climate sensitivity at around 0.6 to 0.8C, rather than the 3.2C assumed by the IPCC climate models.
Forget Tamino's debunk of Spencer. It's junk science and hype at its best.
The physical observations of Spencer et al. on cloud feedbacks have shown that the net overall cloud feedback is strongly negative, rather than strongly positive, as assumed by all the IPCC climate models. And Tamino has not been able to "debunk" this.
Regards,
Max
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Black Wallaby Posted 9:56 am
26 Jan 2009
Tamino is obviously a master of statistics and time series analysis.
ONE of Tamino's favourite topics in supporting MBH99 is PCR analysis, about which, here follows an extract from Wikipedia:
In statistics, principal component regression (PCR) is a regression analysis that uses principal component analysis when estimating regression coefficients.
In PCR instead of regressing the independent variables (the regressors) on the dependent variable directly, the principal components of the independent variables are used. One typically only uses a subset of the principal components in the regression, making a kind of regularized estimation. Often the principal components with the highest variance are selected. However, the low-variance principal components may also be important, -- in some cases even more important.[1]
References: [1] Ian T. Jolliffe (1982). "A note on the Use of Principal Components in Regression". Journal of the Royal Statistical Society, Series C (Applied Statistics) 31 (3): 300-303. R. Kramer, Chemometric Techniques for Quantitative Analysis, (1998) Marcel-Dekker, ISBN: 0-8247-0198-4.
I have highlighted in bold the name of an expert and author, that Tamino has quoted as a leading world expert whom supports Tamino's views on a version of PCR.
Here is Ian Jolliffe's protest at what is either a deliberate misrepresentation of Jolliffe, OR, a demonstration that Tamino does not understand the issues, OR both.
Ian Jolliffe Comments at Tamino: http://www.climateaudit.org/?p=3601
Oh, and BTW, did you Try this from above: http://www.climateaudit.org/?p=2897
This shows that Tamino also has little understanding of the quality of the time series data used by Mann, both in species and many matters such as sample size and illegal extrapolations.
So, I repeat, you said: Tamino is obviously a master of statistics and time series analysis
Why do you say that? The examples I give above seem to say the opposite!
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Black Wallaby Posted 3:05 pm
26 Jan 2009
Nominations @: http://2008.weblogawards.org/nominations/best-science-blo ...
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314159265 Posted 7:03 pm
26 Jan 2009
PCR is quite a complicated thing, incl. confusing terminology.
The Tamino-Jolliffe "affair" is resolved here:
http://tamino.wordpress.com/2008/08/10/open-thread-5-2/
If you're still obsessed with Mann's 1998 hockey stick version, go to climateaudit or visit your psychiatrist.
Quote Jolliffe loc. cit.:
"If there now are people out there claiming that my first post undermines the whole global warming argument, tell me where and I'll refute this misrepresentation as well. Almost any decent statistical model-fitting will give the upward trend at the end of the series, but more importantly there are all the climate models, based mainly on physics rather than statistics, that provide convincing evidence of climate change and the reasons for it. As a statistician, on principle I don't believe anything is absolutely certain, but my view is that the chance of all the climate models having got things completely wrong and that by 2030 the Earth is cooler than in 1950 is of the same order of magnitude as the chance that the USA will decide that independence was a bad idea and ask to be taken back as a British colony by the same date. Not impossible, but I personally wouldn't bet on it."
Mars J. Pictor Florifulgurator, Western Bavarian Forest.
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Black Wallaby Posted 9:32 pm
26 Jan 2009
I am by no means a climate change denier. My strong impress[ion] is that the evidence rests on much much more than the hockey stick. It therefore seems crazy that the MBH hockey stick has been given such prominence and that a group of influential climate scientists have doggedly defended a piece of dubious statistics. Misrepresenting the views of an independent scientist does little for their case either.
Did you miss that last bold bit "Pie"?
You quoted Tamino's "Open thread #5 of 559 posts; BTW, thankyou, I managed to find it: From Ian Jolliffe // September 12, 2008 at 10:44 am
It more or less reflected what was said above, but I wonder why you excluded the following key lead-in sentence from Jolliffe
The only reason I got involved is because the `dubious statistics' were still being defended this year and my name was being used in support.
BTW, did you notice that also amongst the 559 posts was this in part from Jolliffe? Yes it's there, trust me!
Thanks for the apology, Tamino.
Some further clarification: a lot of the confusion seems to have arisen because of the terminology. Uncentred PCA and decentred PCA are completely different animals.
It would be good to return to the topic of this thread as raised by Andrew Dessler The Tamino joke is a short lifetime joke only.
I think Andrew would agree, because whilst Tamino tries to "assASSinate" Spencer, Andrew describes Spencer, (A fellow atmospheric scientist, not a self styled anonymous statistician), as credible.
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manacker Posted 5:09 am
27 Jan 2009
The Ian Jolliffe quote cited by 314159265 makes sense: "the chance of all the climate models having got things completely wrong and that by 2030 the Earth is cooler than in 1950 is of the same order of magnitude as the chance that the USA will decide that independence was a bad idea and ask to be taken back as a British colony by the same date. Not impossible, but I personally wouldn't bet on it."
The warming our planet has experienced over the second half of the 20th century is real even if there may have been some distortions to the temperature record due to the UHI effect.
But let's look more closely at the warming over the second half of the 20th century (1951-2000).
In 1951 the Hadley temperature anomaly was -0.172C.
In 2000 it was +0.238, for a net delta of 0.41C.
The linear rate of warming was 0.0988C per decade or 0.49C over the 50-year period.
The question is not whether or not whether the Earth will be cooler in 2030 than in 1950, i.e. that 50 years of warming from 1951 to 2000 will be reversed by 30 years of even more rapid cooling from 2001 to 2030. This is obviously extremely unlikely to occur, as Ian Jolliffe has correctly suggested.
The real question is whether or not the climate model forecasts made by IPCC and Hadley for accelerated warming over the first decades of the 21st century will truly occur. These forecasts are 0.2C per decade and 0.3C per decade warming, respectively, i.e. two to three times the actually observed warming rate from 1951 to 2000.
The Hadley temperature anomaly in 2001 was 0.40C.
This means that IPCC projects a 2030 temperature anomaly of 0.4 + 3 * 0.2 = 1.0C.
Hadley goes even further to predict 0.4C + 3 * 0.3 = 1.3C.
The first eight full years of the 21st century (2001-2008) have shown a net cooling rate of -0.111C per decade, rather than accelerated warming, as projected by IPCC and Hadley. The anomaly in 2008 was +0.31C, compared to +0.40C in 2001, for a net cooling of almost 0.1C over the period.
I'd say the "jury is very much out" on whether the warming will occur as projected by the IPCC and Hadley climate models. I would even conclude that this is highly unlikely.
To quote Ian Jolliffe, "Not impossible, but I personally wouldn't bet on it."
Max
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manacker Posted 3:31 pm
27 Jan 2009
http://farm4.static.flickr.com/3383/3233586332_484745b123 ...
Jolliffe's "very unlikely" forecast of a complete reversal of 1951-2000 warming by year 2030 is shown as the blue line.
The purple line is a projection based on the continuation of the actual 2001-2008 cooling trend to year 2030. Some solar scientists prefer this projection, but it is probably also unlikely.
The orange line is a somewhat questionable projection by IPCC, whereby the 2001-2008 cooling trend reverses itself drastically from 2008 to 2030 due to AGW.
The red line is an even more unlikely projection by Hadley, whereby the 2001-2008 cooling trend reverses itself even more sharply from 2008 to 2030.
The black dashed line is probably the most likely projection (in my opinion), based on a continuation of the trend from 1951-2000 to year 2030.
But which projection is the right one?
Who knows? Probably neither IPCC nor Hadley. Probably not Andrew Dessler. Certainly not Tamino or me.
Only time will tell.
Max
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manacker Posted 3:36 pm
27 Jan 2009
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314159265 Posted 7:03 pm
27 Jan 2009
My last post here.
Mars J. Pictor Florifulgurator, Western Bavarian Forest.
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manacker Posted 3:18 am
28 Jan 2009
Sure is.
Not the "last twenty-four years of the 20th century" (which have been used by IPCC to "prove" AGW).
The long term trend, stupid, starts with the Hadley record in 1850 and ends with December 2008.
This long term trend shows a linear warming of 0.65 over the entire period, stupid.
Solar scientists have told us (in many studies) that the unusually high level of 20th century solar activity was responsible for around 0.35C (average value of several studies).
This leaves 0.3C for all other causes, including UHI, high level of late 20th century ENSO activity, plus anthropogenic warming (primarily from CO2). Can you follow the arithmetic here?
Let's assume this was ALL due to anthropogenic forcing.
Using the atmospheric CO2 levels assumed by IPCC for 1850 and those measured at Mauna Loa for 2008, we arrive at a 2xCO2 climate sensitivity of around 0.6 to 0.8. This arithmetic is a bit more daunting, but I'll be glad to walk you through it if you're having trouble following.
If we now project that atmospheric CO2 levels will reach twice the 1850 level by year 2100, we can project another 0.4C warming from today until then.
This is what the long-term trend tells us, STUPID.
Max
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Black Wallaby Posted 11:53 am
29 Jan 2009
GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L20704, Received 13 July 2008; revised 16 September 2008; accepted 19 September 2008; published 23 October 2008.
A little more than a year earlier, Spencer, Braswell, Christy, and Hnilo published their findings showing a much higher negative feedback in clouds, (although apparently with smaller global and temporal scope, than yours), which was also published in GRL, thus:
GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L15707,
Received 15 February 2007; revised 30 March 2007; accepted 16 July 2007; published 9 August 2007.
It seems that both papers received similar peer review, and that the latter had wider authorship resources than yours.
It would be of interest to me, and probably Max and other readers here, if you could explain why you do not mention, and by implication, discount the refereed work of these four experts.
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EliRabett Posted 12:20 am
31 Jan 2009
-The Easter Bunny
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manacker Posted 3:15 am
31 Jan 2009
As Black Wallaby pointed out, life would be so much easier if one could make things go away by just denying them or saying "they are as real as the Easter Bunny".
Unfortunately for the negative feedback deniers (like Andrew), it doesn't work out that way in real life.
Max
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Black Wallaby Posted 12:38 pm
01 Feb 2009
So, for example; is Andrew Dessler "right", to not mention the peer reviewed scientific paper by Spencer, Braswell, Christy, and Hnilo, published in the same respected journal as used by Andrew? The point is that the aforesaid paper appears to strongly contradict the main claim in Andrew's lead article, and it is customary in science to mention the work of others in kindred matters!
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Ted Clayton Posted 3:14 pm
01 Feb 2009
First, it's cool you refer to Spencer, Lindzen etc as "credible skeptics". For sure, not all skeptics are the same ...
Now, on the matter of Easter Bunny feedback ... ;-)
I think all natural systems gotta contain/involve both positive & negative feedback elements. Even Venus has negative feedback paths in its climate-system ... even Pluto has positive feedback processes in what passes for its environment.
All atmospheres & their side-loops on planets revolving around suns will be a species of "heat engine", not in principles unlike the boiler, steam-generator, turbine, and steam-condenser of an ordinary electrical generation plant prime-mover (the 'steam plant').
All Carnot cycle systems ('The Word' on heat-engines) - natural & manufactured - contain positive & negative feedback, entropy & enthalpy, inputs & outputs.
No, an atmosphere with only positive feedbacks is too lopsided a model to have any realistic applications.
Now, a model that integrates all known positive & negative feedback loops (they most likely won't all be known..), makes successful predictions and accounts for patterns in previously gathered data-sets - now that's a useful model.
In a situation where we're worried that (a) positive feedback component(s) might be driving the system (the climate) outside a desired range of behavior, we will be looking closely at the feedback 'budget'. When positive feedbacks dominate negative feedbacks, then we expect to see the equilibrium move in one direction - global warming, in this case.
But we don't expect that once a feedback imbalance causes an equilibrium-shift, the parameter-changes will then continue to change indefinitely.
There are still negative feedbacks in operation ... and some of them may not be stable or linear. Just because positive feedback dominates through any given range of the system behavior, doesn't mean it will dominate through the next portion of the range.
Yeah, I'm good with the Easter Bunny. ;-)
Ted Clayton
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Black Wallaby Posted 3:56 pm
13 Feb 2009
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christophersj Posted 7:22 am
14 Feb 2009
"Should the public come to believe that the scientific issues are settled, their views about global warming will change accordingly. Therefore, you need to continue to make the lack of scientific certainty a PRIMARY issue in the debate".
-Frank Luntz
Republican Strategist in 2003
"Tobacco industry documents show that the industry created controversy over the dangers of tobacco smoking, and later passive smoking,[6] without actually denying the claims. A 1969 Brown and Williamson internal document describes the strategy:
"Doubt is our product, since it is the best means of competing with the `body of fact' that exists in the mind of the general public. It is also the means of establishing a controversy. ... Spread doubt over strong scientific evidence and the public won't know what to believe."
The same tactics were used a generation later in the passive smoking debate. A 1988 meeting of the United Kingdom tobacco industry concerned Philip Morris's plans to use "vast sums of money" to fund research that could cast doubt on the health effects of second-hand smoke. Their intention was to "coordinate and pay scientists on an international basis to keep the environmental tobacco smoke controversy alive".[6]"
http://en.wikipedia.org/wiki/Artificial_controversy
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Backcut Posted 9:32 am
14 Feb 2009
http://fhsarchives.wordpress.com/2009/02/10/historian-ste ...
I wonder what the tonnage of GHG's going into the upper atmosphere is. A thick forest can put out up to 100 tons per acre. You can do the conversions and the math.
Scenic pics at http://Lhfotoware.blogspot.com
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Andrew Dessler Posted 2:15 am
15 Feb 2009
You are correct. Uncertainty is one of the key arguments made by skeptics, but it's really quite bogus. I've blogged about this here (also see links therein).
Thanks!
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christophersj Posted 4:30 am
15 Feb 2009
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BobFJ Posted 11:32 am
15 Feb 2009
To recap on your previous positions, your attitude seems to be that unless a scientific paper has been peer reviewed in a respected journal, then it is not worth consideration. Max and me have pointed out to you that Roy Spencer et al have published a peer reviewed paper in GRL which appears to show higher negative feedback from clouds than the positive feedback in water claimed by you, in the very same journal, presumably under a similar referee process. (Geophysical Research Letters)
You have also stated words to the effect, that if total net feedbacks are small or negative, then global warming as a consequence of CO2 alone would not be of serious consequence.
I'm sure that there are many people around who would be pleased to know about the GOOD NEWS that seems to come from Spencer et al, so why don't you answer the enquiries of you?
For instance above @: http://gristmill.grist.org/story/2009/1/21/12834/4508#com ...
Regards, BobFJ AKA Black Wallaby (previously)
Listen to good news
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christophersj Posted 1:40 am
16 Feb 2009
There may or may not be some negative feedbacks revealed. They may or may not be weak or powerful.
But your complaining to Andrew about being off topic is out of line. You are a bully.
If you think you're tired now about pairing your posts with discussions of the Uncertainty Agenda, then you have another thing coming, my friend.
Where is your criticism of right-wing bloggers who conflate La Nina with a long-term global cooling trend?
Nowhere, that's where. You are a biased fraud. Your real intention is to weaken support for the climate treaty.
I'm biased too, but at least I admit it.
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BobFJ Posted 4:56 pm
27 Feb 2009
But your complaining to Andrew about being off topic is out of line. You are a bully.
If you think you're tired now about pairing your posts with discussions of the Uncertainty Agenda, then you have another thing coming, my friend.
Where is your criticism of right-wing bloggers who conflate La Nina with a long-term global cooling trend?
I don't see what that claptrap of yours has to do with the price of cheese!
I'd like to know Andrew's response to the simple unambiguous issue raised @:
http://gristmill.grist.org/story/2009/1/21/12834/4508#com ...
In what way can you explain this to be a biased enquiry?
Listen to good news
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christophersj Posted 6:24 pm
27 Feb 2009
Please allow me to clarify for you:
If you think it is OFF TOPIC, or a non sequitur for anyone to discuss your underlying motivation to create uncertainty around AGW and derail regulation when you post your minutiae, then you may continue to be very, very disappointed.
Skepticism that serves clarity is noble.
Skepticism that serves an agenda against CO2 regulation is offensive.
100% of your skepticism is aimed at discrediting the need for CO2 regulation. And 0% is aimed at false scientific claims from the other side.
That is disingenuous.
If you were truly of benefit to your fellow humans, you would put those cunning brain cells of yours to creating more accuracy and sophistication into the studies of AGW and ocean acidification, not try to UNDERMINE them altogether.
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BobFJ Posted 10:19 pm
27 Feb 2009
I'd like to know Andrew's response to the simple unambiguous issue raised @:
http://gristmill.grist.org/story/2009/1/21/12834/4508#com ... ...
What is it that you ChristophersJ do not understand about the question. Please carefully read what Andrew wrote in his lead article, IN FULL, carefully.
Listen to good news
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manacker Posted 6:34 am
05 Mar 2009
Been following your exchange. It appears to me that Andrew Dessler started the ball rolling with an unsubstantiated claim that "Negative climate feedback is as real as the Easter Bunny".
This was all the more astounding, since it came after the physical observations by Spencer et al., which demonstrated a strong negative feedback from clouds, thereby in effect validating Lindzen's earlier "infrared iris" hypothesis.
So it appears that Andrew's tactic was the classical one of a "denier". When evidence is presented, which goes against the preconceived belief or paradigm, one simply sticks the head in the sand and denies that this evidence exists.
Thomas Kuhn has written about this in his treatise on paradigms. Physical evidence, which refutes the prevailing paradigm, is either ignored, refuted or (in some cases) not even seen. This inability to think outside the box of the prevailing paradigm is, unfortunately, a frequently occurring problem with "mainstream consensus scientists", who have a vested interest in keeping the prevailing paradigm alive, and therefore defend it against any new data that may represent a direct challenge to the paradigm.
I believe this is the crux of the problem here, although I have to admit that Andrew's choice of the "Easter Bunny" was cute.
Max
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