I don’t have much time for a detailed post, a number of people want to discuss sea ice, so here is your chance. We also need to update the ARCUS forecast for August, due Monday August 6th. Poll follows:
Warm:
I take severe exception to your post at August 13, 2012 at 5:10 am which says to me
Please read the recent litterature about “polar amplification” before building “innovative” theories.
Firstly, I am certain I am more familiar with the literature than you because I was answering (at August 13, 2012 at 3:39 am and August 13, 2012 at 4:04 am) your post (at August 13, 2012 at 2:14 am). And your post I was answering cited – and linked to – the argument on a web site where the writer did not know the difference between “insulation” and “insolation”: he had to correct his error in the light of comments on his silly argument. Anybody familiar with the literature would not have provided a link to that web site in support of a claim.
Secondly, I did not “build” any “innovative theories”. I only stated clear facts which are known to everybody familiar with the literature.
Thirdly, your post then cites two climate model studies. I have published on climate models in the peer-reviewed literature. Each climate model emulates a different climate system and there is no known way to discern which one of them – if any – emulates the climate system of the real Earth. Hence, the outputs of the models which you cite are evidence of nothing except the opinions of the teams which constructed those models.
So, in summation, I took the trouble to explain the issues to you when you had demonstrated you did not know them. My explanation presented you with clear, unambiguous facts which included what is known, what cannot be known, and what is probable. Thus, I offered you the opportunity to discuss and/or dispute those facts. Your answer consists of unfounded insults and mere opinions; nothing else.
Please post something sensible or go away.
Richard
Warm
August 13, 2012 8:33 am
“Secondly, I did not “build” any “innovative theories”. I only stated clear facts which are known to everybody familiar with the literature.”
Really ? Please provide links to studies which demonstrate that higer summer insolation has no effect on arctic temperature and sea ice extent…
“Thirdly, your post then cites two climate model studies. I have published on climate models in the peer-reviewed literature. Each climate model emulates a different climate system and there is no known way to discern which one of them – if any – emulates the climate system of the real Earth. Hence, the outputs of the models which you cite are evidence of nothing except the opinions of the teams which constructed those models.”
So… It could be possible to find “modeling” studies that support yours claims.
“My explanation presented you with clear, ous facts which included what is known, what cannot be known, and what is probable.”
My explanation is: more sun, higher temp, less sea ice… It is supported by basic physical assumption, not by complex modeling. And it is supported by paleoclimatic data.
“reduction of the polar ice cap makes very little difference to the absorbtion of solar energy by the Arctic ocean.”
Real data to support your claim ? Here is a recent study that clearly shows the very intense warming of arctic ocean by the sun in the arctic bassin.
Sunlight, water, and ice: Extreme Arctic sea ice melt during the
summer of 2007 http://www.see.ed.ac.uk/~shs/Climate%20change/Data%20sources/Perovic%20ice%20cover.pdf
” An increase in the open water fraction resulted in a 500% positive anomaly in
solar heat input to the upper ocean, triggering an ice–albedo
feedback and contributing to the accelerating ice retreat.”
richardscourtney says:
August 13, 2012 at 3:39 am
Warm:
re. your comment at August 13, 2012 at 2:14 am.
Please remember that the Arctic region is a net emitter of radiation. It obtains little energy from the Sun in the Summer months and none in the winter months.
Some misinformation here: Near the North Pole in June the surface receives about 300 W/m^2 for 24 hours/day. This ‘insulating’ effect of the ice cap is counterbalanced to a small degree by the albedo of ice being greater than that of water: ice reflects more solar radiation than water surface. However, water has little ability to absorb solar radiation near the poles because the angle of incidence is such that calm water would reflect all solar radiation.
Again incorrect, this is only true at sunrise or sunset. At an angle of ~20º above the horizon less than 20% of the incident light is reflected. Of course this is only true for calm water, rough water would reflect less of course. http://upload.wikimedia.org/wikipedia/en/thumb/7/7f/Water_reflectivity.jpg/800px-Water_reflectivity.jpg
richardscourtney
August 13, 2012 10:34 am
Warm:
Your post at August 13, 2012 at 8:33 am asks me
Please provide links to studies which demonstrate that higer summer insolation has no effect on arctic temperature and sea ice extent…
I made no such assertion so I do not need to provide links to prove something I did not say. At August 13, 2012 at 3:39 am I wrote and explained
Hence, reduction of the polar ice cap makes very little difference to the absorbtion of solar energy by the Arctic ocean.
This observation indicates that bottom melting was a major contributor to the 2007 ice loss in the Beaufort Sea. Details of the Beaufort results are presented in Figure 2, which shows the annual cycle of temperature and mass balance from August 2006 through December 2007. For the most part, conditions were typical of thick (3.2 m) multiyear ice in this region: minimum winter air temperatures of 45 C, snow depth of 0.4 m, winter ice growth of 0.33 m, and onset of melt in early June. What was extraordinary was the rapid bottom melting. In the month of August, bottom melting averaged 4 cm per day and reached maximum values of 11 cm per day in the last week of August, compared to characteristic averages of about 1 cm per day for this region [Perovich et al., 2003]. [9] The extreme amount of bottom melting observed in 2007 required considerable heat from the upper ocean.
Earlier work has established the importance of solar heating of open water on bottom melting of the ice [Maykut and McPhee, 1995; Perovich, 2005]. We believe that solar radiation deposited in areas of open water was a primary source of the large amount of ocean heat in 2007. Open water reflects only 7% of the incident solar radiation, compared to 85% for snow-covered sea ice and 65% for bare sea ice. As the ice cover decays, highly reflecting ice is replaced by highly absorbing ocean, resulting in more solar heat absorption and more melting. Furthermore, an ice cover thinned by excessive bottom melt transmits more solar radiation directly to the ocean than the original thicker ice cover. This is the classic ice–albedo feedback mechanism.
(my emphasis RSC)
So, the ice melted from the bottom because of greater heat content in the water below the ice and they say they “believe” this was because of reduced ice albedo.
Well, I could offer you my beliefs: do you want a sermon?
I think the greater heat content in the water had nothing to do with the ice: most of the heat obtained by Arctic water is acquired in warmer regions of the planet (I suggest you do some study on the thermohaline circulation), and it probably varied at some distant location. But that is only my opinion so it cannot be taken as being more valid than their “belief”
In support of your assertion you previously cited opinions, and now you have cited “belief”. I am at a loss to decide which is the less cogent of these unconvincing papers.
At least you are honest enough to admit
My explanation is: more sun, higher temp, less sea ice… It is supported by basic physical assumption, not by complex modeling.
So, in support of your admitted assumption you have only offered insults, opinions and belief.
When assessing the physical world I prefer scientific data to assumptions, opinions and beliefs.
Richard
richardscourtney
August 13, 2012 10:55 am
Phil:
re. your post at August 13, 2012 at 8:57 am.
Please explain why it is cold in the Arctic in the summer.
Richard
richardscourtney says:
August 13, 2012 at 10:55 am
Phil:
re. your post at August 13, 2012 at 8:57 am.
Please explain why it is cold in the Arctic in the summer.
Why? Like you ” I prefer scientific data to assumptions, opinions and beliefs”, which is why I corrected your errors above.
richardscourtney
August 13, 2012 12:14 pm
Phil:
I apologise that I made the mistake of thinking you were attempting to engage in a scientific discussion. In the light of the history of your posts on WUWT, my mistake was foolish.
I made no errors.
I draw your attention to the primer from the US National Snow & Ice Snow Data Centre (NSIDX) at http://nsidc.org/arcticmet/factors/temperature.html
and especially to its illustration titled
“Surface air temperature over the course of a day (data from drifting station NP-30). Top: Temperature on the day of the summer solstice, under constant sunlight. Middle: Temperature at the spring equinox. Diurnal variation is evident. The maximum occurs at about 2 p.m. local time (or 0040 GMT in this case). Bottom: Temperature on the day of the winter solstice, under constant darkness.”
Its text says
Over the course of a day air temperature usually rises from an early morning minimum to an early or midafternoon maximum. This typical pattern can change, however, if an influx of cold air occurs during the same period. Depending on how cold the incoming air is, air temperatures may climb more slowly than usual, may remain steady, or may even fall during daylight hours. Air temperatures may climb through the evening hours as a consequence of strong warm air advection or if cloud cover increases.
And concerning summer temperature
Over the Arctic Ocean, temperatures are close to zero. This occurs because the sea ice cover is at its melting point, which keeps air temperatures near freezing. The autumn months illustrate the transition back to the winter pattern, with higher temperatures over the Atlantic and south of Alaska, and low temperatures over Siberia and the Greenland ice sheet.
We are discussing albedo effects over the Arctic ice cap region. In this context I think you will find this paragraph in the primer is especially instructive
A daily pattern of rising and falling air temperature only holds true during the period of the year when the Arctic receives sunlight. Diurnal temperature variation is most pronounced around the equinox, when the differences in solar radiation from day to night are greatest. The figure below shows the daily cycle of temperatures at three times of the year, using data from a Russian drifting station in the central Arctic Ocean. Note the near-constant temperature of 0 degrees Celsius in midsummer. On bare land, solar radiation is absorbed by soil and re-radiated as heat, but in the Arctic Ocean, energy from solar radiation is spent melting ice and snow, and the air temperature stays near freezing. During polar darkness, when solar radiation is absent, air temperature is strongly controlled by cloud cover. It tends to be colder under clear conditions and warmer under cloudy conditions. Advection of warm or cold air, however, can change these relationships.
It is “colder under clear conditions and warmer under cloudy conditions” in winter because the clouds inhibit radiation from the surface.
Importantly, variations in albedo from ice cap cover are so insignificant that NSIDC does not consider they warrant mention in the primer.
I explained why they are insignificant.
Richard
richardscourtney says:
August 13, 2012 at 12:14 pm
Phil:
I apologise that I made the mistake of thinking you were attempting to engage in a scientific discussion. In the light of the history of your posts on WUWT, my mistake was foolish.
I made no errors.
As pointed out you did! I draw your attention to the primer from the US National Snow & Ice Snow Data Centre (NSIDX) at http://nsidc.org/arcticmet/factors/temperature.html
and especially to its illustration titled
“Surface air temperature over the course of a day (data from drifting station NP-30). Top: Temperature on the day of the summer solstice, under constant sunlight. Middle: Temperature at the spring equinox. Diurnal variation is evident. The maximum occurs at about 2 p.m. local time (or 0040 GMT in this case). Bottom: Temperature on the day of the winter solstice, under constant darkness.”
Why do you draw attention to it, there’s no mention of the two errors you made which I drew your attention to, namely: ” It (the Arctic) obtains little energy from the Sun in the Summer months and none in the winter months”, as I pointed out it’s actually measured at ~300W/m^2 in June near the Pole.
and “However, water has little ability to absorb solar radiation near the poles because the angle of incidence is such that calm water would reflect all solar radiation” again incorrect, data was provided for the reflectivity of water as a function of incident angle.
So yes you did make errors, and obfuscating in an attempt to cover up is getting you nowhere.
richardscourtney
August 13, 2012 2:48 pm
Phil:
I never obfuscate. Please do not attribute your behaviours to others. My purpose in raising those points was to engage you in serious discussion of the pertinent issues. It seems your purpose is your usual snark and knit-picking. So, I write to address your two specific points in hope that serious discussion may ensue.
You claim I made an error because I wrote
It (the Arctic) obtains little energy from the Sun in the Summer months and none in the winter months
You do not dispute that the Arctic region obtains no energy from the Sun in the winter months but you say
it’s actually measured at ~300W/m^2 in June near the Pole.
So, your claim amounts to dispute of the meaning of the word “little” in my statement that the Arctic region “obtains little energy from the Sun in the summer months”.
You say the maximum insolation is typically ~300W/m^2 in June near the Pole. However, this is the maximum, it is less than this in other summer months (n.b. it is zero for half the year; i.e. the winter half). And average insolation over the entire Earth throughout a year is ~1,000W/m^2 at sea level.
Hence, I see no reason to think my statement is an “error”: the word ”little” is appropriate.
And you also claim I made an error because I wrote
However, water has little ability to absorb solar radiation near the poles because the angle of incidence is such that calm water would reflect all solar radiation
and you kindly provided data for the reflectivity of water as a function of incident angle which you think refutes my statement. It is this graph http://upload.wikimedia.org/wikipedia/en/thumb/7/7f/Water_reflectivity.jpg/800px-Water_reflectivity.jpg
You are right in that my word “all” should have been “most”. But that “error” is merely an unintended minor exaggeration which does not alter my argument.
This is because in the Arctic
Open water absorbs the most radiation of all arctic surfaces. With an albedo of about 0.08, it reflects only 8 percent of the incoming radiation. However, the variation of albedo with solar altitude is especially pronounced for the surfaces of oceans and lakes. The albedo of a water surface increases with decreasing solar altitude and approaches a mirror-like 100 percent near sunrise and sunset, or when the sun is low in the arctic sky.
Ref. http://nsidc.org/arcticmet/factors/radiation.html
In the real world Arctic ocean surface is very rarely calm so the fact that it does reflect “100 per cent when the sun is low in the Arctic sky” means that if it were calm then it would reflect 100 per cent when the sun is higher in the Arctic sky. And it is not high in the sky for much of the time.
So, in this case I think you are knit-picking because my unintended exaggeration does not destroy my argument. My entire statement said
This ‘insulating’ effect of the ice cap is counterbalanced to a small degree by the albedo of ice being greater than that of water: ice reflects more solar radiation than water surface. However, water has little ability to absorb solar radiation near the poles because the angle of incidence is such that calm water would reflect all solar radiation. Absorbtion of solar radiation by the Arctic waters requires surface waves which provide absorbing regions over some of their surfaces. Hence, reduction of the polar ice cap makes very little difference to the absorbtion of solar energy by the Arctic ocean.
I twice attempted to engage you in serious discussion. Perhaps you will now have such a serious discussion now I have refuted one of your accusations and I have agreed that I erroneously made an unintended trivial exaggeration.
Richard
Give it up, Phil. The Arctic has gone through exactly the same ice melt in the historical past, most recently in the 1920’s — when CO2 was much lower than now. Here are a few dozen eyewitness accounts.
There is nothing unusual or unprecedented going on. This has all happened repeatedly in the past. So why all the red faced, spittle-flecked, wild eyed arm waving over natural variability? There is no testable scientific evidence that human activity is the cause of Arctic ice melt. None. So get over it. It’s nature at work, nothing more.
Prove me wrong, using the scientific method and testable raw data. Good luck with that; if you can falsify the null hypothesis, you will be the first.
Rob Dekker
August 14, 2012 12:35 am
richardscourtney says :
Rob Dekker:
August 13, 2012 at 12:46 am you ask me: http://wattsupwiththat.com/2012/08/04/weekend-open-thread-2/
Richard, where exactly did Perlwitz suggest that the “global temperature has recently accelerated” in that threat ?
I answer: At August 6, 2012 at 5:06 pm.
…
Please explain why you asked instead of reading the discussion in the thread.
Courtney, what a lame lie to blame your own mistakes on somebody else.
Perlwitz does NOT write (nor suggest) that “global temperature has recently accelerated” in that thread.
You just made that up all by yourself.
Rob Dekker
August 14, 2012 12:56 am
NSIDC record : Arctic sea ice lost 1 million km^2 in one week :
2012, 08, 04, 6.06299,
2012, 08, 05, 5.87559,
2012, 08, 06, 5.81533,
2012, 08, 07, 5.67377,
2012, 08, 08, 5.47461,
2012, 08, 09, 5.23462,
2012, 08, 10, 5.24234,
2012, 08, 11, 5.09222,
Did this ever happen before in satellite recorded history ?
richardscourtney
August 14, 2012 4:00 am
Rob Dekker:
Your post at August 14, 2012 at 12:35 am is a lie. I never “make things up”: please to not attribute your behaviours to others.
The relevant discussion in the thread at http://wattsupwiththat.com/2012/08/04/weekend-open-thread-2/
was about the egregious Perlwitz’s attempt to refute Smokey’s assertion that “global warming has not accelerated recently”.
As I said, in that thread at August 6, 2012 at 5:06 pm he quotes my statement saying:
Simply, Smokey is right that “the trend [in global warming] is not accelerating”, and Perlwitz’s claim that Smokey used the wrong data set merely distracts from the fact that Smokey is right.
The entire discussion was concerning dispute of that statement.
Your assertions are wrong and I am certain you know they are wrong. In the unlikely event that somebody wants to check the matter then they only have to click the link and read the thread. So, go away and do your trolling elsewhere.
Your nonsense is not relevant to this thread and it is a disruption. I shall ignore any more of it.
Richard
richardscourtney
August 14, 2012 4:39 am
Smokey:
The problem is more serious than you state at August 13, 2012 at 6:28 pm.
It is clear that Warm, Phil, Rob Dekker, etc. want to avoid discussion of the science by any means they can. And you are attempting the impossible when you ask these people to use “the scientific method and testable raw data”. They refuse to do it even when provided with the scientific information to use.
The behaviour of Phil is especially informative of their refusal.
August 13, 2012 at 8:57 am Phil attempted to demean (by use of snide and knit-picking) my summation of the science provided to Warm at August 13, 2012 at 3:39 am.
I replied (at August 13, 2012 at 10:55 am) by inviting Phil to have a serious discussion of the issues. I ignored his snide and knit-picking points, and I directed him to the main problem with examination of the subject; viz. the lack of adequate empirical data to determine the relative magnitudes of processes affecting temperature, ice cover and their interaction. I said
Please explain why it is cold in the Arctic in the summer.
This was a direct invitation for him to emphasise the uncertainties which apply to my views.
But Phil ignored that invitation and at August 13, 2012 at 11:07 am he made a silly snide response devoid of any content.
So, at August 13, 2012 at 12:14 pm, I bluntly refuted that I had made errors and I patiently spelled out the issue which supports his views by providing him with direct quotes from NSIDC. For example, this
Over the Arctic Ocean, temperatures are close to zero. This occurs because the sea ice cover is at its melting point, which keeps air temperatures near freezing.
The item I quoted from NSIDC was addressing Arctic temperatures and I conclude my post by saying
Importantly, variations in albedo from ice cap cover are so insignificant that NSIDC does not consider they warrant mention in the primer.
Well, of course this insignificance must be true when “the sea ice cover is at its melting point, which keeps air temperatures near freezing”. And I wrongly assumed Phil would jump on this point so a discussion of the pertinent science would ensue.
But even when deliberately offered this opportunity to proclaim science which supports his view Phil was more concerned to demean science which does not support it by use of insults snide and knit-picking. And that is what he did at August 13, 2012 at 12:41 pm.
I gave up my attempt to engage him in a scientific discussion of the issues and addressed his knit-picking at August 13, 2012 at 2:48 pm.
Clearly, Smokey, you are attempting the impossible when you ask these people to use “the scientific method and testable raw data”. They refuse to do it even when provided with the scientific information to use.
Richard
richardscourtney says:
August 13, 2012 at 2:48 pm
Phil:
I never obfuscate. Please do not attribute your behaviours to others. My purpose in raising those points was to engage you in serious discussion of the pertinent issues.
Well you did on this occasion by raising issues not pertinent to the points I raised. It seems your purpose is your usual snark and knit-picking.
Your one-line, non-responsive challenge to explain the temperature of the Arctic in summer seemed more like snark than a serious attempt to discuss the science. It’s ‘nitpick’ by the way, 😉 So, I write to address your two specific points in hope that serious discussion may ensue.
Good. You claim I made an error because I wrote
It (the Arctic) obtains little energy from the Sun in the Summer months and none in the winter months
You do not dispute that the Arctic region obtains no energy from the Sun in the winter months but you say
“it’s actually measured at ~300W/m^2 in June near the Pole.”
So, your claim amounts to dispute of the meaning of the word “little” in my statement that the Arctic region “obtains little energy from the Sun in the summer months”.
You say the maximum insolation is typically ~300W/m^2 in June near the Pole. However, this is the maximum, it is less than this in other summer months (n.b. it is zero for half the year; i.e. the winter half). And average insolation over the entire Earth throughout a year is ~1,000W/m^2 at sea level.
Actually it’s more like 250W/m^2, the solar constant is ~1370, Bond albedo ~0.31 and to allow for the surface area of the Earth divide by 4. Say a typical value in the tropics of 600W/m^2 for 12 hours compared with 300W/m^2 for 24hrs in the Arctic, so clearly you were in error when you said “that the Arctic region obtains little energy from the Sun in the summer months”. Hence, I see no reason to think my statement is an “error”: the word ”little” is appropriate.
Then we agree to differ, I find it to be inappropriate when the actual situation during the melt season is a solar contribution comparable with the tropics! Not to mention that your knee-jerk response was to deny that you’d made any error at all, it took three posts to admit to a minor error! And you also claim I made an error because I wrote
“However, water has little ability to absorb solar radiation near the poles because the angle of incidence is such that calm water would reflect all solar radiation”
and you kindly provided data for the reflectivity of water as a function of incident angle which you think refutes my statement. It is this graph http://upload.wikimedia.org/wikipedia/en/thumb/7/7f/Water_reflectivity.jpg/800px-Water_reflectivity.jpg
You are right in that my word “all” should have been “most”. But that “error” is merely an unintended minor exaggeration which does not alter my argument.
We obviously speak a different language, a “minor exaggeration” is not describing the situation as 100% (all) when it’s actually more like 20% (a small fraction)!
richardscourtney says:
August 14, 2012 at 4:39 am
August 13, 2012 at 8:57 am Phil attempted to demean (by use of snide and knit-picking) my summation of the science provided to Warm at August 13, 2012 at 3:39 am.
No I didn’t, I spelled out two errors in your summation I’m sorry if having your errors pointed out to you is ‘demeaning’. I replied (at August 13, 2012 at 10:55 am) by inviting Phil to have a serious discussion of the issues. I ignored his snide and knit-picking points, and I directed him to the main problem with examination of the subject; viz. the lack of adequate empirical data to determine the relative magnitudes of processes affecting temperature, ice cover and their interaction.
You did no such thing! You said:
“Please explain why it is cold in the Arctic in the summer.” This was a direct invitation for him to emphasise the uncertainties which apply to my views.
Really, apart from the fact that they had already been pointed out to you, it appears as a snarky remark not an invitation. Your views were flawed because they were based on the following incorrect premises: that the Arctic “obtains little energy from the Sun in the Summer months”, and “water has little ability to absorb solar radiation near the poles because the angle of incidence is such that calm water would reflect all solar radiation” both wrong. But Phil ignored that invitation and at August 13, 2012 at 11:07 am he made a silly snide response devoid of any content.
I asked you ‘Why?’, because it has no relevance to the errors I pointed out to you. Your argument that the surface of the ice is at its melting temperature therefore change in albedo must be insignificant is a non-sequitor.
When presented with the data on light reflectivity by water you don’t address the point, rather you make semantic arguments and still don’t accept your error. Discussing the science with you is very difficult because you refuse to do it!
tjfolkerts
August 14, 2012 1:52 pm
richardscourtney,
You make some good point, but you don’t help the discussion by misquoting.
“Here is the long term trend from the LIA. Notice that the trend is not accelerating.”
Your version of Smokey’s position — with the word “recently” is correct. But his original statement is wrong, Quite simply, the Central England Temperature record (from its start in 1659 through 2011) does indeed show a long-term acceleration. TEMPERATURE = 38.6 - 0.0348 YEAR + 0.000010 YEAR^2
Predictor Coef SE Coef T P
Constant 38.64 11.60 3.33 0.001
YEAR -0.03478 0.01267 -2.75 0.006
YEAR^2 0.00001018 0.00000345 2.95 0.003
In fact, the “acceleration” ( the quadratic term”) is more significant than the slope! Sure there are short periods within the record that have decelerations, but unequivocally, the long-term CET shows a positive acceleration.
For the last 100 years, there is larger, statistically significant acceleration (1.7E-4 vs 0.1E-4).
TEMP_1911 = 650 - 0.662 YEAR + 0.000171 YEAR^2
Predictor Coef SE Coef T P
Constant 650.3 256.8 2.53 0.013
YEAR -0.6616 0.2620 -2.53 0.013
YEAR^2 0.00017073 0.00006680 2.56 0.012
When you stop looking at “long term trends” in the CET, the results change a bit. For the last 30 years or 10 years, the quadratic term is negative (a “deceleration”) but the results are not statistically significant. So, yes, when looking at SHORT-TERM data, there is a (statistically questionable) deceleration.
Richard closes:
Clearly, Smokey, you are attempting the impossible when you ask these people to use “the scientific method and testable raw data”. They refuse to do it even when provided with the scientific information to use.
All of this was presented earlier, but Smokey refused to get engaged at a mathematical level (“I prefer the use of charts and graphs”). It is pretty hard to “prove” anything when people refuse to acknowledge mathematics and statistics.
richardscourtney
August 14, 2012 3:19 pm
tjfolkerts:
Thankyou for your post at August 14, 2012 at 1:52 pm.
I wish it to be clear that I was NOT including you in those who run from scientific discussion. On the contrary, earlier in this thread I thanked you for such a discussion that we had so I am surprised that you thought I was linking you with those I named.
As for the CET, I did not discuss that data set with the egregious Perlwitz. I only put the same points to him that I put to you in this thread. And I thought the honesty of your response in presenting your analysis of running means was an admirable contrast to the behaviour of Perlwiyz in that other thread. Indeed, I thought I had made that clear and I apologise if it was not clear.
That said, I have doubts about the CET and would not choose to defend any argument based on it. My point in the other thread was that Smokey had made a correct assertion and Perlwitz had obfuscated the issue when he jumped in to say Smokey had used the wrong data set. I argued that Smokey’s assertion was correct and that Perlwitz must have known it was correct. Perlwitz refused to agree that Smokey was correct (although it became clear that he did know) and his responses were longwinded examples of pure evasion and obfuscation attempting to suggest that Smokey’s assertion must be wrong.
And I am sorry but we now have a semantic disagreement. As you say, Smokey said
“Here is the long term trend from the LIA. Notice that the trend is not accelerating.”
I understand “is not” refers to the present so the acceleration must refer to recent times. Indeed, my use of the word “recently” states this is my understanding “is not”.
Indeed, Smokey’s assertion – like all his comments – was presented as lack of evidence for AGW. In that context, and if one accepts the validity of the CET, then the fact of acceleration from centuries before the industrial revolution is evidence that the observed rise is not induced by AGW. Indeed, I suspect this is why Perlwitz jumped in to say Smokey had used the wrong data set before anybody could point that out. But I ignored it because I don’t trust the CET.
Just to be clear this time, I thank you for a proper provision of data and your interpretation of it. In my opinion, this is how our discussions should be conducted.
Richard
richardscourtney
August 14, 2012 3:21 pm
Phil:
re your latest post.
I offer some advice.
When you have something to say then say it. Until then stop making a fool of yourself.
Richard
tjfolkerts
August 14, 2012 5:05 pm
Richard,
I was not trying to lump you into the same category as Smokey, and you & I have had some civil and informative discussions. I heartily agree that this is the only way to really approach the “science”.
I also distrust the CET, since it is so localized. I was simply refuting the incorrect conclusion that (for the data set as s whole) there is no acceleration.
You also say “In that context, and if one accepts the validity of the CET, then the fact of acceleration from centuries before the industrial revolution is evidence that the observed rise is not induced by AGW. “
Interpreting this is a bit tricky. I tried running 100 year trends starting every 50 years. Here are the “accelerations” (in microKelvins/year^2) and the p-values for the quadratic term.
1659-1750 +173 0.11
1700-1800 -70 0.37
1750-1850 +21 0.79
1800-1900 -23 0.79
1850-1950 +160 0.23
1900-2000 +58 0.37
So there was a large acceleration early (perhaps due to the end of the Maunder Minimum, or perhaps simply due to poor quality data that early on — but that is purely speculation at this point).
Then there was basically no acceleration for a good 100 years.
Then there was a large acceleration starting around 1850 (the beginning of the effects of the industrial era?)
I was surprised at the small acceleration for 1900-2000, since I remembered posting about a large acceleration in the last century. So I double checked:
1911-2011 +171 0.01.
Rather surprisingly, adding in the recent years with no strong trend makes the long-term acceleration MUCH stronger and MUCH more statistically significant! The lesson seems to be that the “acceleration” term is quite sensitive to the endpoints and all results should be interpreted with care.
(I suspect that using a more global temperature index would produce a more consistent acceleration term, but it is tough to find other good temperature records going back so far.)
Rob Dekker
August 15, 2012 12:38 am
richardscourtney said :
Rob Dekker:
Richard, where exactly did Perlwitz suggest that the “global temperature has recently accelerated” in that threat ?
…
I answer: At August 6, 2012 at 5:06 pm.
…
Rob Dekker:
Perlwitz does NOT write (nor suggest) that “global temperature has recently accelerated” in that thread.
You just made that up all by yourself.
…
Your post at August 14, 2012 at 12:35 am is a lie. I never “make things up”: please to not attribute your behaviors to others.
The relevant discussion in the thread at http://wattsupwiththat.com/2012/08/04/weekend-open-thread-2/
was about the egregious Perlwitz’s attempt to refute Smokey’s assertion that “global warming has not accelerated recently”.
No Courtney, Perlwitz did not “attempt to refute” Smokey’s argument, but instead showed that his argument is flawed (a strawman, if you will) :
Now, I’m glad that Mr. Courtney emphasizes this point, since it makes clear what Smokey and he believe what the alleged contradiction between empirical data and theory was. They believe, if CO2 accelerated after 1940, the global temperature should have accelerated too, if the CO2 increase caused global warming. Only, this argument is logically flawed…
After which he explains exactly WHY Smokey’s argument is flawed.
Now, if the text in that thread no longer seems to support your statements, I’m sorry. But if you really feel you did not make up your allegation against Perlwitz, then please show where Perlwitz suggests that “global temperature has recently accelerated”.
Courtney, you can’t change facts after the facts. That’s not how facts works. No matter how much you try to bluff your way out of this one.
richardscourtney said :
Your nonsense is not relevant to this thread and it is a disruption. I shall ignore any more of it.
Dekker, like Perlwitz, believes that “theory” trumps empirical evidence — a hallmark of the climate alarmist crowd. Of course, it is exactly the reverse: “If it disagrees with [observation] it’s wrong. That’s all there is to it.”
~ R.P. Feynman
Perlwitz wouldn’t know a logicql argument if it bit him on the a… nkle.
richardscourtney
August 15, 2012 1:51 am
tjfolkerts:
Thankyou for your informative post at August 14, 2012 at 5:05 pm.
I agree that
The lesson seems to be that the “acceleration” term is quite sensitive to the endpoints and all results should be interpreted with care.
Indeed, end points are not the only problem with these long data sets. Perhaps the most important issue is the complete impossibility of data validation and lack of knowledge of calibration. As I said, I don’t trust the CET.
There are several other long data sets, notably the Armagh data set, for temperature: Smokey linked to some of them on the other thread. I distrust them all and for the same reasons. An advantage of the CET is that it is not derived from a single location but others are.
Tonyb has done an immense amount of work on these long data sets. And his work comparing historical information to variations in these data sets is both fascinating and astonishing.
I think it would be valuable if you and Tonyb could make contact. The two of you are near opposite ends of the ‘AGW-debate’, you share an interest in the same data, and neither of you addresses the subject in an adversarial or bigoted way.
Richard
richardscourtney
August 15, 2012 1:57 am
Rob Dekker:
I said I would ignore any more of your nonsense but – being of a kindly disposition – I make this single response to you so I can draw your attention to my last post addressed to Phil. And I say to you “Ditto”.
Richard
richardscourtney says:
August 14, 2012 at 3:21 pm
Phil:
re your latest post.
I offer some advice.
When you have something to say then say it. Until then stop making a fool of yourself.
Interesting post, I present actual data refuting your statements and instead of the promised “serious discussion of the pertinent issues”, this is what you come up with. I will take your failure to address the points as an acceptance that the data is correct.
Warm:
I take severe exception to your post at August 13, 2012 at 5:10 am which says to me
Firstly, I am certain I am more familiar with the literature than you because I was answering (at August 13, 2012 at 3:39 am and August 13, 2012 at 4:04 am) your post (at August 13, 2012 at 2:14 am). And your post I was answering cited – and linked to – the argument on a web site where the writer did not know the difference between “insulation” and “insolation”: he had to correct his error in the light of comments on his silly argument.
Anybody familiar with the literature would not have provided a link to that web site in support of a claim.
Secondly, I did not “build” any “innovative theories”. I only stated clear facts which are known to everybody familiar with the literature.
Thirdly, your post then cites two climate model studies. I have published on climate models in the peer-reviewed literature. Each climate model emulates a different climate system and there is no known way to discern which one of them – if any – emulates the climate system of the real Earth. Hence, the outputs of the models which you cite are evidence of nothing except the opinions of the teams which constructed those models.
So, in summation,
I took the trouble to explain the issues to you when you had demonstrated you did not know them. My explanation presented you with clear, unambiguous facts which included what is known, what cannot be known, and what is probable. Thus, I offered you the opportunity to discuss and/or dispute those facts. Your answer consists of unfounded insults and mere opinions; nothing else.
Please post something sensible or go away.
Richard
“Secondly, I did not “build” any “innovative theories”. I only stated clear facts which are known to everybody familiar with the literature.”
Really ? Please provide links to studies which demonstrate that higer summer insolation has no effect on arctic temperature and sea ice extent…
“Thirdly, your post then cites two climate model studies. I have published on climate models in the peer-reviewed literature. Each climate model emulates a different climate system and there is no known way to discern which one of them – if any – emulates the climate system of the real Earth. Hence, the outputs of the models which you cite are evidence of nothing except the opinions of the teams which constructed those models.”
So… It could be possible to find “modeling” studies that support yours claims.
“My explanation presented you with clear, ous facts which included what is known, what cannot be known, and what is probable.”
My explanation is: more sun, higher temp, less sea ice… It is supported by basic physical assumption, not by complex modeling. And it is supported by paleoclimatic data.
“reduction of the polar ice cap makes very little difference to the absorbtion of solar energy by the Arctic ocean.”
Real data to support your claim ? Here is a recent study that clearly shows the very intense warming of arctic ocean by the sun in the arctic bassin.
Sunlight, water, and ice: Extreme Arctic sea ice melt during the
summer of 2007
http://www.see.ed.ac.uk/~shs/Climate%20change/Data%20sources/Perovic%20ice%20cover.pdf
” An increase in the open water fraction resulted in a 500% positive anomaly in
solar heat input to the upper ocean, triggering an ice–albedo
feedback and contributing to the accelerating ice retreat.”
richardscourtney says:
August 13, 2012 at 3:39 am
Warm:
re. your comment at August 13, 2012 at 2:14 am.
Please remember that the Arctic region is a net emitter of radiation. It obtains little energy from the Sun in the Summer months and none in the winter months.
Some misinformation here: Near the North Pole in June the surface receives about 300 W/m^2 for 24 hours/day.
This ‘insulating’ effect of the ice cap is counterbalanced to a small degree by the albedo of ice being greater than that of water: ice reflects more solar radiation than water surface. However, water has little ability to absorb solar radiation near the poles because the angle of incidence is such that calm water would reflect all solar radiation.
Again incorrect, this is only true at sunrise or sunset. At an angle of ~20º above the horizon less than 20% of the incident light is reflected. Of course this is only true for calm water, rough water would reflect less of course.
http://upload.wikimedia.org/wikipedia/en/thumb/7/7f/Water_reflectivity.jpg/800px-Water_reflectivity.jpg
Warm:
Your post at August 13, 2012 at 8:33 am asks me
I made no such assertion so I do not need to provide links to prove something I did not say. At August 13, 2012 at 3:39 am I wrote and explained
“very little difference” is not “no effect”.
Then you claim evidence for your assertion is provided by the paper at
http://www.see.ed.ac.uk/~shs/Climate%20change/Data%20sources/Perovic%20ice%20cover.pdf
It does not provide such evidence. It says
(my emphasis RSC)
So, the ice melted from the bottom because of greater heat content in the water below the ice and they say they “believe” this was because of reduced ice albedo.
Well, I could offer you my beliefs: do you want a sermon?
I think the greater heat content in the water had nothing to do with the ice: most of the heat obtained by Arctic water is acquired in warmer regions of the planet (I suggest you do some study on the thermohaline circulation), and it probably varied at some distant location. But that is only my opinion so it cannot be taken as being more valid than their “belief”
In support of your assertion you previously cited opinions, and now you have cited “belief”. I am at a loss to decide which is the less cogent of these unconvincing papers.
At least you are honest enough to admit
So, in support of your admitted assumption you have only offered insults, opinions and belief.
When assessing the physical world I prefer scientific data to assumptions, opinions and beliefs.
Richard
Phil:
re. your post at August 13, 2012 at 8:57 am.
Please explain why it is cold in the Arctic in the summer.
Richard
richardscourtney says:
August 13, 2012 at 10:55 am
Phil:
re. your post at August 13, 2012 at 8:57 am.
Please explain why it is cold in the Arctic in the summer.
Why? Like you ” I prefer scientific data to assumptions, opinions and beliefs”, which is why I corrected your errors above.
Phil:
I apologise that I made the mistake of thinking you were attempting to engage in a scientific discussion. In the light of the history of your posts on WUWT, my mistake was foolish.
I made no errors.
I draw your attention to the primer from the US National Snow & Ice Snow Data Centre (NSIDX) at
http://nsidc.org/arcticmet/factors/temperature.html
and especially to its illustration titled
“Surface air temperature over the course of a day (data from drifting station NP-30). Top: Temperature on the day of the summer solstice, under constant sunlight. Middle: Temperature at the spring equinox. Diurnal variation is evident. The maximum occurs at about 2 p.m. local time (or 0040 GMT in this case). Bottom: Temperature on the day of the winter solstice, under constant darkness.”
Its text says
And concerning summer temperature
We are discussing albedo effects over the Arctic ice cap region. In this context I think you will find this paragraph in the primer is especially instructive
It is “colder under clear conditions and warmer under cloudy conditions” in winter because the clouds inhibit radiation from the surface.
Importantly, variations in albedo from ice cap cover are so insignificant that NSIDC does not consider they warrant mention in the primer.
I explained why they are insignificant.
Richard
richardscourtney says:
August 13, 2012 at 12:14 pm
Phil:
I apologise that I made the mistake of thinking you were attempting to engage in a scientific discussion. In the light of the history of your posts on WUWT, my mistake was foolish.
I made no errors.
As pointed out you did!
I draw your attention to the primer from the US National Snow & Ice Snow Data Centre (NSIDX) at
http://nsidc.org/arcticmet/factors/temperature.html
and especially to its illustration titled
“Surface air temperature over the course of a day (data from drifting station NP-30). Top: Temperature on the day of the summer solstice, under constant sunlight. Middle: Temperature at the spring equinox. Diurnal variation is evident. The maximum occurs at about 2 p.m. local time (or 0040 GMT in this case). Bottom: Temperature on the day of the winter solstice, under constant darkness.”
Why do you draw attention to it, there’s no mention of the two errors you made which I drew your attention to, namely:
” It (the Arctic) obtains little energy from the Sun in the Summer months and none in the winter months”, as I pointed out it’s actually measured at ~300W/m^2 in June near the Pole.
and “However, water has little ability to absorb solar radiation near the poles because the angle of incidence is such that calm water would reflect all solar radiation” again incorrect, data was provided for the reflectivity of water as a function of incident angle.
So yes you did make errors, and obfuscating in an attempt to cover up is getting you nowhere.
Phil:
I never obfuscate. Please do not attribute your behaviours to others. My purpose in raising those points was to engage you in serious discussion of the pertinent issues. It seems your purpose is your usual snark and knit-picking. So, I write to address your two specific points in hope that serious discussion may ensue.
You claim I made an error because I wrote
You do not dispute that the Arctic region obtains no energy from the Sun in the winter months but you say
So, your claim amounts to dispute of the meaning of the word “little” in my statement that the Arctic region “obtains little energy from the Sun in the summer months”.
You say the maximum insolation is typically ~300W/m^2 in June near the Pole. However, this is the maximum, it is less than this in other summer months (n.b. it is zero for half the year; i.e. the winter half). And average insolation over the entire Earth throughout a year is ~1,000W/m^2 at sea level.
Hence, I see no reason to think my statement is an “error”: the word ”little” is appropriate.
And you also claim I made an error because I wrote
and you kindly provided data for the reflectivity of water as a function of incident angle which you think refutes my statement. It is this graph
http://upload.wikimedia.org/wikipedia/en/thumb/7/7f/Water_reflectivity.jpg/800px-Water_reflectivity.jpg
You are right in that my word “all” should have been “most”. But that “error” is merely an unintended minor exaggeration which does not alter my argument.
This is because in the Arctic
Ref. http://nsidc.org/arcticmet/factors/radiation.html
In the real world Arctic ocean surface is very rarely calm so the fact that it does reflect “100 per cent when the sun is low in the Arctic sky” means that if it were calm then it would reflect 100 per cent when the sun is higher in the Arctic sky. And it is not high in the sky for much of the time.
So, in this case I think you are knit-picking because my unintended exaggeration does not destroy my argument. My entire statement said
I twice attempted to engage you in serious discussion. Perhaps you will now have such a serious discussion now I have refuted one of your accusations and I have agreed that I erroneously made an unintended trivial exaggeration.
Richard
Give it up, Phil. The Arctic has gone through exactly the same ice melt in the historical past, most recently in the 1920’s — when CO2 was much lower than now. Here are a few dozen eyewitness accounts.
There is nothing unusual or unprecedented going on. This has all happened repeatedly in the past. So why all the red faced, spittle-flecked, wild eyed arm waving over natural variability? There is no testable scientific evidence that human activity is the cause of Arctic ice melt. None. So get over it. It’s nature at work, nothing more.
Prove me wrong, using the scientific method and testable raw data. Good luck with that; if you can falsify the null hypothesis, you will be the first.
richardscourtney says :
Courtney, what a lame lie to blame your own mistakes on somebody else.
Perlwitz does NOT write (nor suggest) that “global temperature has recently accelerated” in that thread.
You just made that up all by yourself.
NSIDC record : Arctic sea ice lost 1 million km^2 in one week :
2012, 08, 04, 6.06299,
2012, 08, 05, 5.87559,
2012, 08, 06, 5.81533,
2012, 08, 07, 5.67377,
2012, 08, 08, 5.47461,
2012, 08, 09, 5.23462,
2012, 08, 10, 5.24234,
2012, 08, 11, 5.09222,
Did this ever happen before in satellite recorded history ?
Rob Dekker:
Your post at August 14, 2012 at 12:35 am is a lie. I never “make things up”: please to not attribute your behaviours to others.
The relevant discussion in the thread at
http://wattsupwiththat.com/2012/08/04/weekend-open-thread-2/
was about the egregious Perlwitz’s attempt to refute Smokey’s assertion that “global warming has not accelerated recently”.
As I said, in that thread at August 6, 2012 at 5:06 pm he quotes my statement saying:
The entire discussion was concerning dispute of that statement.
Your assertions are wrong and I am certain you know they are wrong. In the unlikely event that somebody wants to check the matter then they only have to click the link and read the thread. So, go away and do your trolling elsewhere.
Your nonsense is not relevant to this thread and it is a disruption. I shall ignore any more of it.
Richard
Smokey:
The problem is more serious than you state at August 13, 2012 at 6:28 pm.
It is clear that Warm, Phil, Rob Dekker, etc. want to avoid discussion of the science by any means they can. And you are attempting the impossible when you ask these people to use “the scientific method and testable raw data”. They refuse to do it even when provided with the scientific information to use.
The behaviour of Phil is especially informative of their refusal.
August 13, 2012 at 8:57 am Phil attempted to demean (by use of snide and knit-picking) my summation of the science provided to Warm at August 13, 2012 at 3:39 am.
I replied (at August 13, 2012 at 10:55 am) by inviting Phil to have a serious discussion of the issues. I ignored his snide and knit-picking points, and I directed him to the main problem with examination of the subject; viz. the lack of adequate empirical data to determine the relative magnitudes of processes affecting temperature, ice cover and their interaction. I said
This was a direct invitation for him to emphasise the uncertainties which apply to my views.
But Phil ignored that invitation and at August 13, 2012 at 11:07 am he made a silly snide response devoid of any content.
So, at August 13, 2012 at 12:14 pm, I bluntly refuted that I had made errors and I patiently spelled out the issue which supports his views by providing him with direct quotes from NSIDC. For example, this
The item I quoted from NSIDC was addressing Arctic temperatures and I conclude my post by saying
Well, of course this insignificance must be true when “the sea ice cover is at its melting point, which keeps air temperatures near freezing”. And I wrongly assumed Phil would jump on this point so a discussion of the pertinent science would ensue.
But even when deliberately offered this opportunity to proclaim science which supports his view Phil was more concerned to demean science which does not support it by use of insults snide and knit-picking. And that is what he did at August 13, 2012 at 12:41 pm.
I gave up my attempt to engage him in a scientific discussion of the issues and addressed his knit-picking at August 13, 2012 at 2:48 pm.
Clearly, Smokey, you are attempting the impossible when you ask these people to use “the scientific method and testable raw data”. They refuse to do it even when provided with the scientific information to use.
Richard
richardscourtney says:
August 13, 2012 at 2:48 pm
Phil:
I never obfuscate. Please do not attribute your behaviours to others. My purpose in raising those points was to engage you in serious discussion of the pertinent issues.
Well you did on this occasion by raising issues not pertinent to the points I raised.
It seems your purpose is your usual snark and knit-picking.
Your one-line, non-responsive challenge to explain the temperature of the Arctic in summer seemed more like snark than a serious attempt to discuss the science. It’s ‘nitpick’ by the way, 😉
So, I write to address your two specific points in hope that serious discussion may ensue.
Good.
You claim I made an error because I wrote
It (the Arctic) obtains little energy from the Sun in the Summer months and none in the winter months
You do not dispute that the Arctic region obtains no energy from the Sun in the winter months but you say
“it’s actually measured at ~300W/m^2 in June near the Pole.”
So, your claim amounts to dispute of the meaning of the word “little” in my statement that the Arctic region “obtains little energy from the Sun in the summer months”.
You say the maximum insolation is typically ~300W/m^2 in June near the Pole. However, this is the maximum, it is less than this in other summer months (n.b. it is zero for half the year; i.e. the winter half). And average insolation over the entire Earth throughout a year is ~1,000W/m^2 at sea level.
Actually it’s more like 250W/m^2, the solar constant is ~1370, Bond albedo ~0.31 and to allow for the surface area of the Earth divide by 4. Say a typical value in the tropics of 600W/m^2 for 12 hours compared with 300W/m^2 for 24hrs in the Arctic, so clearly you were in error when you said “that the Arctic region obtains little energy from the Sun in the summer months”.
Hence, I see no reason to think my statement is an “error”: the word ”little” is appropriate.
Then we agree to differ, I find it to be inappropriate when the actual situation during the melt season is a solar contribution comparable with the tropics! Not to mention that your knee-jerk response was to deny that you’d made any error at all, it took three posts to admit to a minor error!
And you also claim I made an error because I wrote
“However, water has little ability to absorb solar radiation near the poles because the angle of incidence is such that calm water would reflect all solar radiation”
and you kindly provided data for the reflectivity of water as a function of incident angle which you think refutes my statement. It is this graph
http://upload.wikimedia.org/wikipedia/en/thumb/7/7f/Water_reflectivity.jpg/800px-Water_reflectivity.jpg
You are right in that my word “all” should have been “most”. But that “error” is merely an unintended minor exaggeration which does not alter my argument.
We obviously speak a different language, a “minor exaggeration” is not describing the situation as 100% (all) when it’s actually more like 20% (a small fraction)!
richardscourtney says:
August 14, 2012 at 4:39 am
August 13, 2012 at 8:57 am Phil attempted to demean (by use of snide and knit-picking) my summation of the science provided to Warm at August 13, 2012 at 3:39 am.
No I didn’t, I spelled out two errors in your summation I’m sorry if having your errors pointed out to you is ‘demeaning’.
I replied (at August 13, 2012 at 10:55 am) by inviting Phil to have a serious discussion of the issues. I ignored his snide and knit-picking points, and I directed him to the main problem with examination of the subject; viz. the lack of adequate empirical data to determine the relative magnitudes of processes affecting temperature, ice cover and their interaction.
You did no such thing! You said:
“Please explain why it is cold in the Arctic in the summer.”
This was a direct invitation for him to emphasise the uncertainties which apply to my views.
Really, apart from the fact that they had already been pointed out to you, it appears as a snarky remark not an invitation. Your views were flawed because they were based on the following incorrect premises: that the Arctic “obtains little energy from the Sun in the Summer months”, and “water has little ability to absorb solar radiation near the poles because the angle of incidence is such that calm water would reflect all solar radiation” both wrong.
But Phil ignored that invitation and at August 13, 2012 at 11:07 am he made a silly snide response devoid of any content.
I asked you ‘Why?’, because it has no relevance to the errors I pointed out to you. Your argument that the surface of the ice is at its melting temperature therefore change in albedo must be insignificant is a non-sequitor.
When presented with the data on light reflectivity by water you don’t address the point, rather you make semantic arguments and still don’t accept your error. Discussing the science with you is very difficult because you refuse to do it!
richardscourtney,
You make some good point, but you don’t help the discussion by misquoting.
No, what Smokey said is
Your version of Smokey’s position — with the word “recently” is correct. But his original statement is wrong, Quite simply, the Central England Temperature record (from its start in 1659 through 2011) does indeed show a long-term acceleration.
TEMPERATURE = 38.6 - 0.0348 YEAR + 0.000010 YEAR^2
Predictor Coef SE Coef T P
Constant 38.64 11.60 3.33 0.001
YEAR -0.03478 0.01267 -2.75 0.006
YEAR^2 0.00001018 0.00000345 2.95 0.003
In fact, the “acceleration” ( the quadratic term”) is more significant than the slope! Sure there are short periods within the record that have decelerations, but unequivocally, the long-term CET shows a positive acceleration.
For the last 100 years, there is larger, statistically significant acceleration (1.7E-4 vs 0.1E-4).
TEMP_1911 = 650 - 0.662 YEAR + 0.000171 YEAR^2
Predictor Coef SE Coef T P
Constant 650.3 256.8 2.53 0.013
YEAR -0.6616 0.2620 -2.53 0.013
YEAR^2 0.00017073 0.00006680 2.56 0.012
When you stop looking at “long term trends” in the CET, the results change a bit. For the last 30 years or 10 years, the quadratic term is negative (a “deceleration”) but the results are not statistically significant. So, yes, when looking at SHORT-TERM data, there is a (statistically questionable) deceleration.
Richard closes:
All of this was presented earlier, but Smokey refused to get engaged at a mathematical level (“I prefer the use of charts and graphs”). It is pretty hard to “prove” anything when people refuse to acknowledge mathematics and statistics.
tjfolkerts:
Thankyou for your post at August 14, 2012 at 1:52 pm.
I wish it to be clear that I was NOT including you in those who run from scientific discussion. On the contrary, earlier in this thread I thanked you for such a discussion that we had so I am surprised that you thought I was linking you with those I named.
As for the CET, I did not discuss that data set with the egregious Perlwitz. I only put the same points to him that I put to you in this thread. And I thought the honesty of your response in presenting your analysis of running means was an admirable contrast to the behaviour of Perlwiyz in that other thread. Indeed, I thought I had made that clear and I apologise if it was not clear.
That said, I have doubts about the CET and would not choose to defend any argument based on it. My point in the other thread was that Smokey had made a correct assertion and Perlwitz had obfuscated the issue when he jumped in to say Smokey had used the wrong data set. I argued that Smokey’s assertion was correct and that Perlwitz must have known it was correct. Perlwitz refused to agree that Smokey was correct (although it became clear that he did know) and his responses were longwinded examples of pure evasion and obfuscation attempting to suggest that Smokey’s assertion must be wrong.
And I am sorry but we now have a semantic disagreement. As you say, Smokey said
I understand “is not” refers to the present so the acceleration must refer to recent times. Indeed, my use of the word “recently” states this is my understanding “is not”.
Indeed, Smokey’s assertion – like all his comments – was presented as lack of evidence for AGW. In that context, and if one accepts the validity of the CET, then the fact of acceleration from centuries before the industrial revolution is evidence that the observed rise is not induced by AGW. Indeed, I suspect this is why Perlwitz jumped in to say Smokey had used the wrong data set before anybody could point that out. But I ignored it because I don’t trust the CET.
Just to be clear this time, I thank you for a proper provision of data and your interpretation of it. In my opinion, this is how our discussions should be conducted.
Richard
Phil:
re your latest post.
I offer some advice.
When you have something to say then say it. Until then stop making a fool of yourself.
Richard
Richard,
I was not trying to lump you into the same category as Smokey, and you & I have had some civil and informative discussions. I heartily agree that this is the only way to really approach the “science”.
I also distrust the CET, since it is so localized. I was simply refuting the incorrect conclusion that (for the data set as s whole) there is no acceleration.
You also say “In that context, and if one accepts the validity of the CET, then the fact of acceleration from centuries before the industrial revolution is evidence that the observed rise is not induced by AGW. “
Interpreting this is a bit tricky. I tried running 100 year trends starting every 50 years. Here are the “accelerations” (in microKelvins/year^2) and the p-values for the quadratic term.
1659-1750 +173 0.11
1700-1800 -70 0.37
1750-1850 +21 0.79
1800-1900 -23 0.79
1850-1950 +160 0.23
1900-2000 +58 0.37
So there was a large acceleration early (perhaps due to the end of the Maunder Minimum, or perhaps simply due to poor quality data that early on — but that is purely speculation at this point).
Then there was basically no acceleration for a good 100 years.
Then there was a large acceleration starting around 1850 (the beginning of the effects of the industrial era?)
I was surprised at the small acceleration for 1900-2000, since I remembered posting about a large acceleration in the last century. So I double checked:
1911-2011 +171 0.01.
Rather surprisingly, adding in the recent years with no strong trend makes the long-term acceleration MUCH stronger and MUCH more statistically significant! The lesson seems to be that the “acceleration” term is quite sensitive to the endpoints and all results should be interpreted with care.
(I suspect that using a more global temperature index would produce a more consistent acceleration term, but it is tough to find other good temperature records going back so far.)
richardscourtney said :
No Courtney, Perlwitz did not “attempt to refute” Smokey’s argument, but instead showed that his argument is flawed (a strawman, if you will) :
After which he explains exactly WHY Smokey’s argument is flawed.
Now, if the text in that thread no longer seems to support your statements, I’m sorry. But if you really feel you did not make up your allegation against Perlwitz, then please show where Perlwitz suggests that “global temperature has recently accelerated”.
Courtney, you can’t change facts after the facts. That’s not how facts works. No matter how much you try to bluff your way out of this one.
richardscourtney said :
Then why did you bring it up in the first place ?
Dekker, like Perlwitz, believes that “theory” trumps empirical evidence — a hallmark of the climate alarmist crowd. Of course, it is exactly the reverse: “If it disagrees with [observation] it’s wrong. That’s all there is to it.”
~ R.P. Feynman
Perlwitz wouldn’t know a logicql argument if it bit him on the a… nkle.
tjfolkerts:
Thankyou for your informative post at August 14, 2012 at 5:05 pm.
I agree that
Indeed, end points are not the only problem with these long data sets. Perhaps the most important issue is the complete impossibility of data validation and lack of knowledge of calibration. As I said, I don’t trust the CET.
There are several other long data sets, notably the Armagh data set, for temperature: Smokey linked to some of them on the other thread. I distrust them all and for the same reasons. An advantage of the CET is that it is not derived from a single location but others are.
Tonyb has done an immense amount of work on these long data sets. And his work comparing historical information to variations in these data sets is both fascinating and astonishing.
I think it would be valuable if you and Tonyb could make contact. The two of you are near opposite ends of the ‘AGW-debate’, you share an interest in the same data, and neither of you addresses the subject in an adversarial or bigoted way.
Richard
Rob Dekker:
I said I would ignore any more of your nonsense but – being of a kindly disposition – I make this single response to you so I can draw your attention to my last post addressed to Phil. And I say to you “Ditto”.
Richard
richardscourtney says:
August 14, 2012 at 3:21 pm
Phil:
re your latest post.
I offer some advice.
When you have something to say then say it. Until then stop making a fool of yourself.
Interesting post, I present actual data refuting your statements and instead of the promised “serious discussion of the pertinent issues”, this is what you come up with. I will take your failure to address the points as an acceptance that the data is correct.