Image Credit: WoodForTrees.org
Guest Post By Werner Brozek, Edited By Just The Facts
RSS stands for Remote Sensing Systems, which is a satellite temperature data set similar to the University of Alabama – Huntsville (UAH) dataset that John Christy and Roy Spencer manage. Information about RSS can be found at here and the data set can be found here.
The plot of the number on the left column from November 1, 1996 to October 31, 2013 can be found in the graph at the head of his article and here. When the “Raw data” is clicked, we see that for 204 months, the slope is = -0.000122111 per year. I wish to make it perfectly clear that the focus is not on the magnitude of the negative number since this number is zero for all intents and purposes. The only thing that is noteworthy is that the slope is not positive.
And of course, 204 months is equal to 17 years. In the “Separating signal and noise in atmospheric temperature changes: The importance of timescale” Benjamin Santer et al. stated that:
“Our results show that temperature records of at least 17 years in length are required for identifying human effects on global-mean tropospheric temperature.”
I am sure that I will be corrected if I am wrong, but in plain English, my interpretation of this statement is as follows:
“There is a lot of noise in the climate system and it is quite possible that the noise can mask the effects of man-made carbon dioxide for a period of time. However if the slope is zero for 17 years, then we cannot blame noise any more but we have to face the facts that we humans do not affect the climate to any great extent.”
Is that reasonably accurate interpretation?
Richard Courtney offered a very interesting perspective in a comment previously:
“The Santer statement says that a period of at least 17 years is needed to see an anthropogenic effect. It is a political statement because “at least 17 years” could be any length of time longer than 17 years. It is not a scientific statement because it is not falsifiable.
However, if the Santer statement is claimed to be a scientific statement then any period longer than 17 years would indicate an anthropogenic effect. So, a 17-year period of no discernible global warming would indicate no anthropogenic global warming.
In my opinion, Santer made a political statement so it should be answered with a political response: i.e. it should be insisted that he said 17 years of no global warming means no anthropogenic global warming because any anthropogenic effect would have been observed.
Santer made his petard and he should be hoisted on it.”
Some may wonder why I am ignoring UAH. In response, I would just say that while UAH does not have a slope of 0 over the last 17 years, within the error bars of statistical significance, it is indeed possible for UAH to have a slope of 0 for this period of time. Nick Stokes’ Trend Viewer page shows: “CI from -0.384 to 2.353“. So while a larger trend cannot be ruled out, a slope of 0 is certainly possible according to climate science criteria for statistical significance.
You may be interested in how the other data sets compare over this same 17 year period. My recent post Statistical Significances – How Long Is “The Pause”? (Now Includes September Data) offers an in depth analysis and below is the plot for five other data sets. In addition to the RSS plot using all points for RSS and its slope line, I have just drawn the slope lines for the other five and offset them so they all start at the point where RSS starts in November 1996.
It is interesting to note that over this same 17 year period, the largest slope is that of UAH with 0.009/year or less than 1 degree C/century. That is certainly nothing to be alarmed about.
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I hate to say this, but you have missed something in Santer’s belief system that he obviously expected to be taken for granted. When Santer wrote:
“Our results show that temperature records of at least 17 years in length are required for identifying human effects on global-mean tropospheric temperature.”
He intended this corollary to be taken for granted: “Of course that only applies to warming, but if we measure no changes at all for 17 years then it might take 25 or 50 or 100 years to see the Global Warming, because it’s tricky that way, and it hides in all the spooky places like a Halloween goblin – and just when you think it’s gone for good it’ll jump out of the Deep Ocean or something and shout “BOOGA BOOGA BOOGA!!!”
Warmists must be well qualified as groundsmen considering the number of times they’ve moved the goalposts.
I interpret the “at least 17 years” statement differently. It is meaningless to look at temperature changes of shorter duration because of natural variability. Only after that period of time will the human effect be measurable. This is a slow motion fight that “denialists” are going to win one month at a time. We only had to wait 17 years. Problem is, living in a cold climate, I didn’t really want to be on the winning team.
WoodForTrees have periods with negative trends during other long periods.
1944-1978 as an example-over 30 years.
Refuting CAGW and the growth of a plague of locusts both require 17 years.
So, let’s recap the year in climate so far, shall we?
* The Nenana, Alaska “ice out” date breaks the old record.
* Arctic minimum sea ice extent rebounds sharply from 2012 lows.
* Antarctic maximum sea ice extent sets new records.
* Tornado activity to date is near record lows.
* The hurricane season in the Atlantic basin has been (and probably will end up being) a dud.
* We have now reached 17 years with zero trend in “global temperature”.
Others can add to the list…
The goal posts will be moved soon and we will see that we need 25-30 years of non warming.
It is a bit like the timing of the end of the world madmen, everytime we reach it some excuse is used and a new date is given.
Do not make the mistake that Climate ” Science” has anything to do with real science!
Does this mean that taxes on fuel and subsidies on wind and solar power will go?
I doubt it, no doubt “it will be the wrong 17 years”, or “the models are now predicting this lack of warming, because the heat is going into the ocean” (regardless of the fact that the atmosphere has to heat up first before the seas can).
As Bloke Down the Pub states, they will move the goalposts again by making up some total c**p about the “travesty” that they don’t know what has happened to the missing heat. If it helps I can tell them that heat and temperature are not synonymous; the same as climate and weather in fact!
oppti says:
November 4, 2013 at 6:51 am
This implies faith in the accuracy of the ground (and ocean) record.
The significance of the RSS records is that it covers very nearly the entire planet with a consistent measure.
Personally I’m waiting (hopefully) for the 20 year mark. Because then the 1980-2000 (roughly speaking) rise will be no longer than the 2000-2020 level/cooling period. I don’t think AGW will survive that. We’re nearly three quarters of the way there, as the years tick by the warmists will be getting more and more worried. I think post 2015 the cracks will really begin to show as more rats leave the sinking ship.
So, what the consensus (yerch) of the length of warming, 1978-1998? Once the length of the pause equals the length of warming (I don’t mind a little overlap), it will be harder for people to claim X years is too short without putting doubt on the the warming period being long enough to be significant.
Ric Werme 7:00
Ok so what is the RSS reading for the period 1944-1978?
Climate has long time periodicity, something CO2 has not changed completely!
Of course if we wait long enough it will go up again. Or down. In fact, if we wait long enough it will probably dice carrots.
Steve from Rockwood is mostly right, but I object to the idea that 17 years would “always and forever” be long enough to see thru the varibilities that may occur. Even though that period length may be long enough to cover the past occurances, that doesn’t mean it woud cover future situations. There is no limit that I know of to the extent of natural variability possible. There is a more important issue by far in all this : how much anthropogenic warming are we talking about? Whether or not anthropogenic warming is statistically significantly greater than zero (which is the question answered by statistical significance tests) has nothing whatsoever to do with the issue of whether the warming is indeed significant, or worrisome. One should instead statistically evaluate the data to answer whether one can be certain that warming greater than some agreed to magnitude is occurring. A warming of 2/10ths degrees per century might very well be shown to be statistically significant (which it is). But it’s not significant in any other way. “Statistical significance” is by far the most misunderstood scientific term. No one seems to know what it actually represents
“Is that reasonably accurate interpretation?”
Werner,
Yes. Although Santer doesn’t say it directly, Figures 4 and 6 make clear what he means. In an ensemble of model runs, over a period of 17 years, only 2.5% of models have a negative trend. As seen in Figure 6a, over 14 years only 5% of model runs have a negative trend. And as seen in Figure 4b, over 20 years only about 0.5% of model runs have a negative trend. Since the 95% confidence interval determines statistical significance, one can say that a non-positive trend over 17 years or longer would imply that the models are wrong. They must either have the wrong trend or they must have a too-low variability. If scientists are being honest, they must acknowledge and confront this discrepancy, though they can try to save the CAGW claims by arguing that the variability, not the trend, is what’s wrong.
”
Is that reasonably accurate interpretation?
no.
and courtney botches it as well.
As people have already noted, the goalpost shifting will soon begin, with warmists ready with a veritable bank of excuses as to why the Earth hasn’t warmed or indeed started to cool!!!! Under no circumstances could they be wrong!
oppti says:
November 4, 2013 at 6:51 am
“WoodForTrees have periods with negative trends during other long periods.
1944-1978 as an example-over 30 years.”
So the rise of CO2 from 1960 to 1978 had no effect as well?
http://www.woodfortrees.org/plot/esrl-co2
That’s great! We can dump the doubly falsified CO2AGW theory! Rejoyce! Thermageddon ain’t gonna happen! Dance in the streets, warmists! You’re saved!
As to us skeptics; we didn’t worry about it anyway so we’ll just continue working.
Steven Mosher:
At November 4, 2013 at 7:35 am your post says in total
Please explain how I have botched it.
I await your explanation in awe and anticipation of your wisdom.
Richard
Does anyone know how many years of warming there had been by 1984 when Hansen started saying the world was going to burn up and the West Side Hwy in NYC would be under water? Had it been at least 17 years?
Steve Mosher, what is the significance, if any, of 17 years without warming wrt Santers statement? (This is not a provocative question, I sincerely want to know how you interpret this.)
To oppti:
You wrote:
However, the UN IPCC has put forth the statement that man-made greenhouse
gas emissions began to dominate the Earth’s climate beginning in 1976. So
the earlier periods of negative slope are less relevant.
From: Phil Jones [p.jones@uea.ac.uk]
Sent: Thu 07/05/2009 15:17
to: “Lockwood, M (Mike)”
Bottom line – the no upward trend has to continue for a total of 15 years before we get worried. We’re really counting this from about 2004/5 and not 1998.
There will be a new version of HadCRUT3 (which we will call HadCRUT4!)
################
The goal post have already begun to move.
Steven Mosher says:
November 4, 2013 at 7:35 am
”
Is that reasonably accurate interpretation?
no.
and courtney botches it as well.
Let me try:
What Santer meant was that we must wait to see what the 17 year data shows and then we can determine whether the data means anything meaningful or not.
If it shows warming, it is meaningful, but if it shows either flat temps or any level of cooling, then we must investigate further.
It appears he rejected Nancy Pelosi’s suggestion – “We must analyze the data before we see it.”
🙂
@ur momisugly andrewmharding
Why should the subsidies go? Nuclear power has been subsidized by an order of magnitude or more based on real dollars; for development of the basic tecnology, for construction of power stations, and development of fuel. Without conversion of weapons stockpiles for fuel, or a transition to thorium reactors, there is not enough U3O8 production capacity to support the expansion of Nuclear power as a significant contributor to electricity. There is barely enough to meet demand now. Approximately 68,000 tons of U3O8 is needed in 2013 http://www.world-nuclear.org/info/Facts-and-Figures/World-Nuclear-Power-Reactors-and-Uranium-Requirements/ (that is a nuclear industry site) — production worldwide – 58,000 tons http://www.world-nuclear.org/info/Facts-and-Figures/Uranium-production-figures/
That is a 16% shortfall — just to maintain the current reactor force.
Oil demand exceeds supply now by several hundred thousand barrels a day. The production shortfall is projected to be a few million barrels per day by Q4 2014. http://omrpublic.iea.org/
Oil is not viable in the very near term. Nuclear is not viable for at least a decade, yet rooftop solar can be done in a month, and a wind farm can be sited and producing in a year or 2.