From Wikipedia:
Polar amplification is the greater temperature increases in the Arctic compared to the earth as a whole as a result of the effect of feedbacks and other processes. It is not observed in the Antarctic, largely because the Southern Ocean acts as a heat sink and the lack of seasonal snow cover. It is common to see it stated that “Climate models generally predict amplified warming in polar regions”, e.g. Doran et al.
Now with this paper, blowing the surface data out for AGW effects, what are they going to do?
Via the Hockey Schtick:
New paper finds only 1 weather station in the Arctic with warming that can’t be explained by natural variation
A paper published today in Geophysical Research Letters examines surface air temperature trends in the Eurasian Arctic region and finds “only 17 out of the 109 considered stations have trends which cannot be explained as arising from intrinsic [natural] climate fluctuations” and that “Out of those 17, only one station exhibits a warming trend which is significant against all three null models [models of natural climate change without human forcing].” Climate alarmists claim that the Arctic is “the canary in the coal mine” and should show the strongest evidence of a human fingerprint on climate change, yet these observations in the Arctic show that only 1 out of 109 weather stations showed a warming trend that was not explained by the natural variations in the 3 null climate models.
Note a “null model” assumes the “null hypothesis” that climate change is natural and not forced by man-made CO2 or other alleged human influences.
GEOPHYSICAL RESEARCH LETTERS, VOL. 39, L23705, 5 PP., 2012
doi:10.1029/2012GL054244
On the statistical significance of surface air temperature trends in the Eurasian Arctic region
Key Points
- I am using a novel method to test the significance of temperature trends
- In the Eurasian Arctic region only 17 stations show a significant trend
- I find that in Siberia the trend signal has not yet emerged
C. Franzke
British Antarctic Survey, Natural Environment Research Council, Cambridge, UK
This study investigates the statistical significance of the trends of station temperature time series from the European Climate Assessment & Data archive poleward of 60°N. The trends are identified by different methods and their significance is assessed by three different null models of climate noise. All stations show a warming trend but only 17 out of the 109 considered stations have trends which cannot be explained as arising from intrinsic [natural] climate fluctuations when tested against any of the three null models. Out of those 17, only one station exhibits a warming trend which is significant against all three null models. The stations with significant warming trends are located mainly in Scandinavia and Iceland.
Introduction
[2] The Arctic has experienced some of the most dramatic environmental changes over the last few decades which includes the decline of land and sea ice, and the thawing of permafrost soil. These effects are thought to be caused by global warming and have potentially global implications. For instance, the thawing of permafrost soil represents a potential tipping point in the Earth system and could lead to the sudden release of methane which would accelerate the release of greenhouse gas emissions and thus global warming.
[3] Whilst the changes in the Arctic must be a concern, it is important to place them in context because the Arctic exhibits large natural climate variability on many time scales [Polyakov et al., 2003] which can potentially be misinterpreted as apparent climate trends. For instance, natural fluctuations on a daily time scale associated with weather systems can cause fluctuations on much longer time scales [Feldstein, 2000; Czaja et al., 2003; Franzke, 2009]. This effect is called climate noise. Even very simple stationary stochastic processes can create apparent trends over rather long periods of time; so-called stochastic trends [Cryer and Chan, 2008; Cowpertwait and Metcalfe, 2009; Barbosa, 2011; Fatichi et al., 2009; Franzke, 2010, 2012]. On the other hand, a so-called deterministic trend arises from external factors like greenhouse gas emissions.
[4] Specifically, here I will ask whether the observed temperature trends in the Eurasian Arctic region are outside of the expected range of stochastic trends generated with three different null models of the natural climate background variability. Choosing the appropriate null model is crucial for the statistical testing of trends in order not to wrongly accept a trend as deterministic when it is actually a stochastic trend [Franzke, 2010, 2012].
[5] There are two paradigmatic null models for representing climate variability: short-range dependent (SRD) and long-range dependent (LRD) models [Robinson, 2003; Franzke, 2010, 2012; Franzke et al., 2012]. In short, SRD models are the most used models in climate research and represent the initial decay of the autocorrelation function very well. For instance, a first order autoregressive process (AR(1)) has an exponential decay of the autocorrelation function. LRD models represent the low-frequency spectrum very well, have a pole at zero frequency and a hyperbolic decay of the autocorrelation function. One definition of a LRD process is that the integral over its autocorrelation function is infinite while a SRD process has always an integrable autocorrelation function [Robinson, 2003; Franzke et al., 2012]. In general, both stochastic processes can generate stochastic trends but stochastic trends of LRD models can last for much longer than stochastic trends of SRD models. This shows that the rate of decay of the autocorrelation function has a strong impact on the length of stochastic trends. In addition to these two paradigmatic models we will also use a non-parametric method to generate surrogates which exactly conserve the autocorrelation function of the observed time series. Figure 1 displays the autocorrelation function for one of the used stations and the corresponding autocorrelation functions of the above three models. It has to be noted that there are a myriad of nonlinear stochastic models which can potentially be used to represent the background climate variability and the significance estimates will depend on the used null model. However, I have chosen the three above models because two of them represent paradigmatic models for representing the correlation structure and one conserves exactly the empirical correlation structure.
Figure 2. Map of stations: Magnitude of the observed trend in °C per decade.
Results
[17] Figure 2 displays the location of all stations and the colour coding indicates the magnitude and sign of the temperature trends. The first thing to note is that all stations experience a warming trend over their respective observational periods. The largest trends (more than 0.4°C per decade) are in central Scandinavia and Svalbard. Most of Siberia experienced warming trends of about 0.2–0.3°C per decade.
[18] After finding evidence for warming trends we have now to assess their statistical significance; do the magnitudes of the observed trends lie already outside of the expected range of natural climate variability? The above three significance tests reveal that 17 of the 109 stations are significant against an AR(1) null model (Figure 3a), 3 stations are significant against a ARFIMA null model (Figure 3b), and 8 stations are significant against a climate noise null hypothesis using phase scrambling surrogates (Figure 3c). All these trends are significant at the 97.5% confidence level. This shows that while the Eurasian Arctic region shows a widespread warming trend, only about 15% of the stations are significant against any of the three significance tests.
Figure 3. Stations with a statistically significant trend against (a) AR(1), (b) ARFIMA, (c) phase scrambling null model and (d) stations with a significant trend: blue: weak evidence, green: moderate evidence and red: strong evidence.
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“Now with this paper, blowing the surface data out for AGW effects, what are they going to do?”
Nothing they just ignore it 😉
Are not “the stations with significant warming trends located mainly in Scandinavia and Iceland” those adjusted? See:
http://wattsupwiththat.com/2012/03/11/another-giss-miss-warming-in-the-arctic-the-adjustments-are-key/
I think the indicated warming is like the MWP, very localized. /sarc
Could there be one location on the planet with statistically significant cooling?
Cue up Queen: “Another one bites the dust.”
And the data recently measured was compared to a time period of duration
25 years? 50? 200? 1000? 10000? years?
“Now with this paper, blowing the surface data out for AGW effects, what are they going to do?”
They will ignore it, just like all the other evidence that refutes the AGW hypothesis.
As I have said before, the AGW movement is a POLITICAL movement in which “science” is used advance a political ideology .
It is no coincidence that the AGW movement began in earnest upon the fall of the USSR and that probably 98% of the AGW zealots are liberal progressives, socialists or communists.
The science does not matter at all. No more than misery and poverty in Czarist Russia was caused by the Kulaks; an invention of the Bolsheviks to advance their tyrannical, murderous cause.
“Out of those 17, only one station exhibits a warming trend which is significant against all three null models [models of natural climate change without human forcing].”
“NULL MODELS … of natural climate change without human forcing” ??!
But we are constantly lectured that the null hypothesis is stasis, that nothing other than stasis “can be imagined by Ben Santer”, or that CAGW IS in fact the new null hypothesis.
Now this outbreak of sanity … the null hypothesis is normality, i.e. natural climate change (oscillation).
Noteworthy indeed – a move in the right direction.
108 canaries are singing at the top of their lungs, but not to worry: one quiet canary is all the alarmists need…even if they parade it in an oversized coffin, march it through the streets at the head of a huge procession and bury it with full media attention.
Another arrow in the elephant.
Figure 1 that Willis provided the other day showed clearly that the Arctic temperatures were not correlated with global warming. This current paper now confirms Willis’ findings. The Arctic is not a canary for climate change.
“Significance against the null hypothesis” is a grey area. All of the stations exhibit warming. The warming does not come with a label identifying its proximate cause, probably because it doesn’t have a “proximate” cause — as the paper notes, a lot of what one sees is basically amplified noise with varying autocorrelation lifetimes. The “climate”, then, is determined by a highly non-Markovian integrodifferential process which stretches “proximate cause” out over anywhere from years to decades into the past (if not longer, since it is a global integrodifferential process where an ENSO strength fluctuation in a different hemisphere altogether two or more decades in the past can still be influencing the polar climate today in the sense that it would be very different had that fluctuation not occurred).
One is left right where one started. This in no way disproves the hypothesis that CO_2 caused the anomalous strength of the ENSO fluctuation in 1998 that is almost single-handedly responsible for the step-function bump in global mean temperatures in both SSTs and LTTs, which in turn is still affecting/producing Arctic warming in some regions due to peculiarities in the phases of the other decadal oscillations. Nor is it possible to prove that CO_2 caused the 1998 ENSO bump, because we don’t know the baseline.
This is the one thing that drives me nuts. We do not know the baseline. We do not know how to compute the null hypothesis warming without unprovable assumptions, any more than we know how to assign observed warming to CO_2 vs natural without CO_2 — they are one and the same. We have no idea why the Earth warmed into the MWP, cooled into the LIA, or why it has warmed since. We do now know how to predict what it would have done if CO_2 had never exceeded (say) 300 ppm. We do not know what is driving its long term trends or the strength of those forces, only that those forces historically have been capable of producing 1-2C century scale variations in temperature independent of CO_2 level over hundreds of thousands if not millions of years, in ice age or out of ice age. Are they amplified noise in a marginally stable externally forced nonlinear chaotic coupled oscillator system? Are they strictly following macroscopic orbital forcings?
We may, quite literally, never know, or at least not know in my lifetime and beyond. We might still not know 100 years from now. We aren’t ever going to have particularly high resolution or accurate estimates of global temperatures from the pre-thermometric past, because the second law of thermodynamics and the great eraser, entropy, has had centuries to millions of years to blur the record and we don’t seem to be able to do a very good job at estimating global temperatures in the contemporary present with actual thermometers stuck into the planet all over the place and satellite thermometers taking global atmospheric or SS temperatures pretty much all of the time. I just don’t think people appreciate how profound our ignorance here really is, how overstated our knowledge of the remote past (or even the relatively recent past) is.
If one believes the “best” proxy reconstructions of temperatures over the last 20,000 or so years, one doesn’t have to resort to fancy statistical methods to prove that we don’t know whether the current warming is due to natural variations or CO_2 (or rather, how to apportion the observed warming between the two). It is perfectly obvious that the climate system can make it much warmer or much cooler than it is today without any really significant change in either atmospheric composition or orbital stance, and that it can accomplish this on the timescale of centuries at rates of + or – 0.1-0.3 C/decade without any visible or definite proximate cause!
Which is the end of the story, at least until we can assign a proximate case to each and every major climate variation of the last 20,000 years, in detail. When we can explain, in full non-equilibrium thermodynamic regalia, why the MWP and LIA happened and why they were as large or small as they were, then perhaps we can think about understanding the present. But we can’t, and we don’t and we won’t be able to until we can, which may well be never, given that we cannot go back in time and measure many of the things that might have contributed to the “proximate cause” in this non-Markovian multivariate nonlinear chaotic system with a highly variable driver.
rgb
How many Arctic stations are impacted by anthropogenic albedo mods, and, anthropogenic surface and near-surface energy dissipation?
hmmm. There have been an increase in papers that are extremely cautious about CAGW lately. To pun, there is a bit of ice breaking going on.
rgb–just type “CO2”, as in one atom of carbon and two atoms of oxygen. The underscore in your compound representation isn’t necessary. 🙂
Key Points
* I am using a novel method to prove this point that I think is true.
Not again. Stats is simple, no need to re-invent it…
Two points:
– The paper recognizes that “All stations show a warming trend”. Just pointing this out because I still see a lot of folks who deny the official line that warming, for whatever reason, is occurring.
– the paper’s results depend on models. A lot of criticism I’ve heard from the climate change denial side (e.g. Monckton) is over scientists’ use of models. I’m glad to see so many people here favorable of results emanating from models. Long may it continue.
Chris B says:
December 11, 2012 at 7:28 am
I hope not, Chris–the longer this planet keeps warming, the longer the next Ice Age will be delayed. And just think of the beneficial levels of CO2 we’re seeing–simply amazing!
Plants are growing like they’ve not been in 200+ years and they even need less water! The Sahel is expanding on the south of the Saraha and someday I hope this conversion to a more abundant biosphere turns that entire Sahara wasteland into one big pasture for cows, horses, and goats.
What’s not to like, eh?
(Kinda takes the air out of those windbag Warmistas that can’t see anything but gloom and doom every mourning they wake up–“mourning” misspelled on purpose, of course.)
Canaries in coalmines, eh? Bad analogy. It’s CO (Carbon Monoxide) that kills the poor canaries they take down into coal mines.
Garrett says:
December 11, 2012 at 8:21 am
Could you please supply a list of “folks who deny the officieal line” for us, Garrett?
Thanks in advance.
Add the stations in Alaska as well. Only one is obeying ‘polar amplification'(Barrow)…all the rest are trending with the PDO.
http://www.benthamscience.com/open/toascj/articles/V006/111TOASCJ.pdf
Fred Allen’s right. This paper contains statistical proof that there is significant warming in the Arctic that cannot be explained from natural causes. The fact that only 1 station exhibits this will be quietly forgotten.
Garrett says:
December 11, 2012 at 8:21 am
If you could please offer a link showing where Monckton is on the “climate change denial side”, I’d love to see it, Garrett.
Otherwise, I believe you owe Lord Monckton a public apology.
And then back to the books for you.
Garrett says:
December 11, 2012 at 8:21 am
If you could please offer a link showing where Monckton is on the “climate change denial side”, I’d love to see it, Garrett.
Otherwise, I believe you owe Lord Monckton a public apology.
And then back to the books for you.
rgbatduke says:
“This is the one thing that drives me nuts. We do not know the baseline. We do not know how to compute the null hypothesis warming without unprovable assumptions, any more than we know how to assign observed warming to CO_2 vs natural without CO_2 — they are one and the same.”
Only one thing about this drives you nuts? How can one have a baseline in a continuously changing system with a large number of intercorrelated variables for which cause and effect are unknown and possibly unknowable? Modeling the climate is a fools’ errand, being carried out by fools, who do not know, nor care one iota about science. It’s all about power and money, as are most political endeavors.
He has probably got the figures upside down – he’s from the British ANtarctic Survey! 🙂
In general, over all the world, about 1/3 of all thermometers – surface stations – show a cooling trend over the past 60+ years.
About 1/6 show no trend at all.
Only the remainder, just slightly over 1/2 of all stations, actually show a positive trend in temperatures.
So, despite all the hype and exaggerations from the CAGW propagandists intended to cost the planet millions from increased deaths from cold, starvation and illness and bad food and bad water – the 1/3 of one degree increase in temperatures advertised as “Catastrophic Global Warming” is only true for half of the thermometers in use.