Open thread Dec. 9, 2014 Dan Crawford | December 9, 2014 6:10 am Tags: open thread Comments (29) | Digg Facebook Twitter |
Joel tells us: “There has been no pause… ” Skeptics start their calculations from the end of current measurement data which makes the claim a mathematical near impossibility. All that is needed is measurement data that remains within the margin of error. The only possible discussion point is its length.
There can be discussion of what the definition of the pause might be, but no matter how it is defined it doesn’t change the mathematical certitude of its existence. A definition which is based upon anything but a zero trend line will extend the length of the pause.
What is happening, however, is that many claiming the “pause” is nonexistent or question its validity start from some other date, usually ~1998. They then go into some statistical gymnastics to show how it is not happening. I will repeat: START AT THE END OF THE AVAILABLE MEASUREMENT DATA AND WORK BACKWARDS. Then we can discuss length and the statistical significance of that trend.
The pause hypothesis can be stated very simply. Starting at the end of the data how long is the 0 trend? Any other proof is for some OTHER HYPOTHESIS and comparing apples to “the pause”.
So you are in error.
Let me see if I understand what you are saying. The way to determine if there is a pause, or to determine the length of the pause, is to start with the most current data and work backwards until the trend in the data is no longer zero. Is that what you are saying?
That is the hypothesis skeptics are using.
Dear AT&T U-Verse Marketing Department:
Please stop with the unceasing multiple sales pitches per week via my postal mailbox. You have been contributing mightily to the waste can near it with all manner of appeals. I realize you are under pressure to sign up as many subscribers as possible with the looming presence of Google Fiber in Austin to your long term mysteriously unclear pricing plans. But I kept thinking after I refused not only to respond to your junk mail but also turned away many of your in-person representatives from my door that it had to stop.
After I started having trouble with my DSL yesterday you even turned that into a sales pitch. The helpful and perky Kristen reassured me that I’d be much happier once I made the switch to U-Verse’s reliable fiber and away from “the expensive to repair and maintain old copper wires”. But I calmly explained to Kristen that I thought it important to keep using those old expensive copper wires for a simple reason: They are installed and maintained by CWA represented technicians who earn a living wage and decent benefits (for now). I also noted that although some U-Verse installation workers had been included in CWA negotiating units they do not currently earn the same pay and benefits that wire line techs receive.
I also noted with some dismay the recent comments by your CEO Randall Stephenson regarding Net Neutrality re: his plans to halt investment in the very technology you are asking me to support as a customer. This represents yet another quandary beyond the lack of CWA representation among U-Verse installers. Net Neutrality is an important issue to this AT&T customer so if AT&T needs it stopped to justify investment in U-Verse I guess I have another reason to stick with my regulated old copper wire interface to your network.
Perhaps at some point you will learn that this customer wants his internet service provided by workers who earn pay and benefits that will allow them to participate fully in the economic growth they are creating in this new economy. Send me a sales pitch for U-Verse that emphasizes your organizations fair treatment of installation workers and maintenance technicians and you will get my order immediately.
Maybe I can beat Beverly to it, but is there any good reason why Obama should not ask for the CIA chief’s resignation in view of his already debunked claim that the CIA’s torture of Muslims saved lives? I mean I get that Obama did not have the political stomach to go back and determine who might be prosecuted for what I consider “crimes against humanity” notwithstanding Alberto Gonzalez’ stirring defense-not. And to bring this full circle back to a “slightly left of center economics blog” since World War II haven’t we mostly messed around in the internal affairs of other countries primarily to prevent the spread of communism? Which has lead to large segments of the world’s population hating us not for our “freedom” but for our insistence that our exploitative brand of capitalism predominate. And isn’t that really conducting foreign policy on behalf of a very small special interest group–the 1 per cent? And isn’t it bad enough that the 1 % insist that we all share the cost of a foreign policy that many of us do not want, but it leads to the wholesale disregard of whatever modicum of decency this country had? And quite apart from the racial aspects does anyone else see the militarization of the country’s police force as a deliberate tactic by the one per cent to keep the rabble–ie the other 99% including I would guess just about everyone who participates in this blog–in line?
CoRev – “That is the hypothesis skeptics are using.”
So, what they should do is start at some earlier date and work forward?
We’re not trying to determine past trends, but how long this one is. If you want to use a different hypothesis, it’s fine. Don’t be surprised when you’re accused of cherry picking, or someone shows you the SkS escalator. 😉
OK, work with me here. You’re saying we’re in a pause. The only question is, how long is it? We should start with the most current data, and then work backwards until the trend is no longer zero?
Jerrry Critter, it’s already been cone by Ross McKitrick
It was one of the papers Tamino was referencing in his article.
Since you sucked me into following the links the other day, I now have something to add.
In order to meaningfully follow the discussion, you need more than a passing knowledge of statistics. Most people with a single statistics class never really come to understand confidence limits.
You can analyze almost any problem in multiple ways. If you want to get people to agree about the results, you need to make sure the question to be answered is posed very, very carefully. The question of whether we are in a pause is not carefully posed.
The Tamino analysis is not done the way I (probably) would, but it does make clear that if the question is “given that there was an increase with a known (including error limits) slope, has the slope changed (per that data set) since 1998 to a 95 percent confidence limit?”, then the answer is “no pause”. It also ends up showing that (per that analysis method) with the current variance, it would require almost 20 years of pause to reach a 95 percent confidence limit.
A lot of the discussion indicates that scientists are more than willing to hypothesize about the reasons for the pause even though the pause is not statistically conclusive.
When you see people disagreeing about what the termperature data say, you should suspect that they are not using the same null hypothesis and\or confidence limits.
Arne, I agree with the comment: ” …they are not using the same null hypothesis and\or confidence limits.” The null hypothesis for the skeptics/McKitrick’s test of the pause is: Starting for the data endpoint there is no ZERO trend, and for how long? The other hypothesis is: Starting at the data endpoint there is a zero trend, and it is (how many temporal units) long.
IIRC, Tamino did not use either of the hypotheses. W. M. Briggs, another statistician, http://wmbriggs.com/blog/ has this rule (paraphrased) always question a statistician that goes beyond the simple test answering the original question. (Keep it simple stupid).
When you look at Tamino’s efforts using this rule, it becomes obvious what is being done, sowing confusion amongst the less knowledgeable.
Which brings up this question. Why is it so important to disprove the existence of the “pause”?
“Why is it so important to disprove the existence of the “pause”?
Cause total ahs have convinced other total ahs that there has been a pause and clog up the world with utter bs.
Like anything done by McKitrick, who may even have surpassed Spencer with his long history of being wrong, if not corrupt.
“When you look at Tamino’s efforts using this rule, it becomes obvious what is being done, sowing confusion amongst the less knowledgeable.”
And why have you not confronted Tamino with this charge?
Philip Shehan says:
8 Dec 2014 at 7:36 AM
I actually emailed McKitrick about his paper and he was courteous enough to reply. He specifically refuted claims made for his paper, that it showed statistically significant periods of pause for the time periods quoted.
His method, strange or not, actually gives trends and 95% error margins that are very close to those delivered by Kevin Cowtan’s algorithm, except for UAH data where McKitrick claims the “hiatus” started in 1998:
0.061 ±0.120 °C/decade
Trend: 0.062 ±0.221 °C/decade (2σ)
McKitrick’s error is in concluding that the period when warming ceases to be statistically significant equates to the beginning of a hiatus or pause.
Non statistically significant warming does not mean no warming, statistically significant or otherwise.
I don’t know why the UAH result is so different. I don’t know what algorithm is used on the SKS website. Also there might have been revisions to the UAH data set since I accessed it.
My calculations didn’t aim to measure a statistically-significant trend in the neighbourhood of zero, instead I was aiming to measure how far back the hiatus apparently started.
Dr. Ross McKitrick”
With regards to the oft heard claim of no warming since 1998.
Here is the skeptic Roy Spencer’s UAH data:
The el nino year of 1998 creates a reduction in the atmospheric warming rate if you take it as the start point. Wait another year until that effect is gone and it is warming as usual, paralleling the increase in CO2 concentration.
No (atmospheric) warming (or even reduced warming) for 16 years but warming as usual for 15 years is a logical nonsense based on a misinterpretation of the data.
Sixteen years ago there was an exceptionally hot year. That is all.”
– See more at: http://www.realclimate.org/index.php/archives/2014/12/recent-global-warming-trends-significant-or-paused-or-what/comment-page-2/#comments
CoRev – “The other hypothesis is: Starting at the data endpoint there is a zero trend, and it is (how many temporal units) long.”
So, using the “other hypothesis”, you are assuming there is a pause, and calculating its length (which may be very short). On the other hand, if your starting point is at an earlier date and you are working forward, you are assuming a trend, and looking for a pause.
Sorry if I am over-simplifying a complicated concept, but I am trying to understand it without going back to college.
Jerru Critter, you are absolutely correct, which is why I said it is with mathematical near certitude that there is a pause. after the many claims of cherry picking etc. it verifies what the eyes are telling us.
EM, I’m trying to discover the meaning in your comment. Is it this: ” McKitrick’s error is in concluding that the period when warming ceases to be statistically significant equates to the beginning of a hiatus or pause.
Non statistically significant warming does not mean no warming, statistically significant or otherwise.”? Or did you have another message?
Its also very hard to tell where your own thought/analysis starts and stops in your comment.
EM, I see we had a couple of comments crossing the wires simultaneously.
EM re: your comment about the pause and BS and reread what I said about near mathematical certainty. If you don’t understand it ask Jerry Critter.
As for going to Tamino’s blog and commenting, I’ve already been banned for pointing out discrepancies. If you have a problem with my comments then refute it.
I referenced WM Briggs earlier. One of his rules is: ” If we want to know if there has been a change from the start to the end dates, all we have to do is look! I’m tempted to add a dozen more exclamation points to that sentence, it is that important. We do not have to model what we can see. No statistical test is needed to say whether the data has changed. We can just look. ” http://wmbriggs.com/blog/?p=5107
” I’ve already been banned for pointing out discrepancies.”
The point of the post is that unless the starting point is 1998(and actually 6 months of 1998), there is a constant warming. Your talk about other people cherry picking is inane when that fact is seen.
EM, prove it? How would I do that to your satisfaction???? But here is an example of one of his attempts to modify an comment: http://tamino.wordpress.com/2014/06/03/teachable-moment/#comment-86742 Notice the s? What did he edit? What I have seen is parts of comments actually edited to change their meaning. Believe or not? It’s no matter to me.
On your point of the post: “The point of the post is that unless the starting point is 1998(and actually 6 months of 1998), there is a constant warming.” That’s a cherry picked date. Its also not th4e same hypothesis.
The actual zero trend runs to ~ 1996.65 not (your preferred cherry picked date 1997.5 to 1998). The start date will shift forward and back slightly, until we reach a sustained period of relatively high warming. Since we are using monthly and yearly averages that will take some time. Even if this year is the warmest on record due to the el Nino, the next year should drop and the zero trend re-establish.
The key is that the warm period must be sustained to make a mathematical difference. The current peaks and valleys in monthly measurements mostly offset. A sustained cool or zero trend will add to both ends of the trend.
Tamino and the RC crowd surely know this. The question remains why the obfuscation and fight to disprove the very existence of the pause?
Why does it even matter if we are in a pause? From this discussion, it seems like having a pause is simply a matter of picking the right data interval and the direction (forward or backwards) of analysis. Is any trend, up, down, or zero, over a period of a few years really significant in answering the overall question,
Is the earth getting warmer?
Is not there a general agreement that the answer to that question is yes?
Jerry Critter, you hit upon a truth. The planet has gotten warmer since the Little Ice Age (LIA). The issue is from what causes? How much of the warming is from each cause? The traditional climate hypothesis claims it is from the (GHE) Green House Effect caused by Green House Gases GHGs) by slowing the loss of Infrared Radiation to space cooling the planet. From that basic hypothesis we have a follow-on that the main GHG is CO2 and that mankind is the largest creator of CO2 (ACO2). All of that has been implemented into government policies to curb the creation of ACO2.
What is settled of this hypothesis is this: CO2 is a GHG. GHGs do slow the loss of IR. Nealy ALL heat is from the Sun and its short wave radiation. Everything else is estimate and/or conjecture. Ever since Arrhenius discovered and documented the impact of GHGs, all ensuing estimates of their warming impacts have been wrong. THE PAUSE HIGHLIGHTS SOME SERIOUS QUESTIONS/DOUBTS regarding the basic hypothesis and especially the impact of ACO2. The latest IPCC Report lowered the impact from the previous Report, and more recent science has estimated even lower impacts.
Today climate science is realized by the climate models. They too are wrong, diverging from observations. Climate models are the sum of the existing climate science, and if wrong indicate some serious flaws. Many skeptics would claim they over emphasize the impact of CO2 (especially ACO2) on the GHE.
The most recent science aimed at explaining the “pause” now point to the impact of the oceans. Unlike atmospheric GHGs which can only slow the loss of IR for relatively short periods, while the oceans can sequester the heat for centuries and even perhaps millenia.
On an economics blog the costs to followup/implement these Government policies based upon what may be flawed science should be a discussion point. It seldom happens, and is openly discouraged at this blog.
Jerry Critter let me handle these two questions apart: 1) Why does it even matter if we are in a pause? 2) From this discussion, it seems like having a pause is simply a matter of picking the right data interval and the direction (forward or backwards) of analysis.”
1A) The pause is important because it raises serious questions over the validity of the current climate science conclusions.
2A) Are we arming overall? Since when? How much? How much can be assigned to which cause? Pause tells us not now in the period of the MEASURED data. The period covered by the measured data is actually not significant length of time when compared to the major climate cycles, THE GLACIATIONS. In that time frame we have this pattern: http://farm5.staticflickr.com/4111/4994030265_2de8169af7_z.jpg
From that graph we can see that this period is not even as warm as previous warm periods. That is born out by ice core graphs of the Southern hemisphere and not just these Greenland graphs.
So the science is consistent in saying that overall the Holocene is slowly cooling, and this period although warmer than the LIA, cooler than the previous which was cooler than its previous, etc. Science also tells us we are approaching the end of this inter-glacial period.
I think it is important to know that this warm period is just temporary. Sometime the planet will eventually start the next glaciation. Maybe some day we’ll know enough about the climate to recognize the importance of these various short term fluctuations.
CoRev – “I think it is important to know that this warm period is just temporary. ”
Do you say that because all previous warm periods have ended? Aren’t you completely discounting any effect from human activity?
Jerry Critter,no! I’m not discounting anything, but I am insisting that we actually do not know how much warming is caused by any of the factors. Therefore any expensive or draconian policies are much riskier than doing nothing.
Much riskier how? (1) We will over-correct and start a severe cooling trend? Or (2) create severe economic effects, effects that we can predict with even worse accuracy than climate change? So far, doing nothing hasn’t been working so well.
Jerry Critter, how do we even know this? ” So far, doing nothing hasn’t been working so well.” That’s exactly what the “pause” tells us. What we are doing has little to no effect. Natural effects are overwhelming any of the human (good or bad) influences.
Since this is an economics blog I would concentrate upon the economic impacts of following stricter policies. We can look across the Atlantic to see just some of those impacts and unintended consequences.
On the over-correct issue, the only way I can see that happening is with some badly though out Geo-engineering attempt to change climate/weather. None are serious proposals at this time.
BTW, implicit in your question see you still believe warming is worse than ??? Is there any non-modeled evidence for this? Just what could be done to mitigate that/those effects. Most efforts to date are attempts to slow or reduce the human foot print. How do we stop human population growth and economic advancement? Is that even a good idea?
That is your example?
It is just like your posts.
Go play golf somewhere.