Roger Pielke Sr. has joined Anthony Watts in la-la-land with a post which was also posted on WUWT, Pielke Senior: Arctic Temperature Reporting In The News Needs A Reality Check; it’s Pielke’s attempt to throw dirt at the recent Kaufman et al. research. Pielke refers to modern arctic temperatures thus:
The documentation of their biased reporting is easy to show. For example, they do not report on observational data which does not show this rapid recent warming; e.g. see that the current high latitude temperatures are close to the longer term average since 1958The Danish Meteorological Institute Daily Mean Temperatures in the Arctic 1958 – 2008 [and thanks to the excellent weblog Watts Up With That for making this easily available to us!]
As for current high-latitude temperatures being close to the longer term average since 1958, no they’re not. Pielke and Watts need a sanity check.
One of the most interesting aspects of the arctic hockey stick is that until the recent and sizeable man-made warming, arctic temperatures weren’t flat, they were actually declining. This is no surprise at all, because orbital factors have a strong influence on polar temperature; in fact they’re the trigger for ice ages. It turns out that the orbital changes over the last 10,000 years have had a cooling influence on the arctic.
The phrase “orbital factors” in this context actually includes an astronomical aspect which is not orbital: the earth’s obliquity. Obliquity is the angle by which our planet is tilted relative to its orbit. The earth’s axial tilt is what gives us our seasons, but the amount of that tilt (the obliquity) is not perfectly constant; it varies between a minimum of about 22o and a maximum of about 24.5o. When the tilt is greater, the poles receive more energy from the sun, both at the peak of midsummer and averaged throughout the year. Obliquity is currently in decline, as it has been since about 10,000 years ago:
Note that the time coordinate is thousands of years from the year 2,000, so “0″ is today and “-10″ is 10,000 years ago, or 8,000 B.C.
Another important factor affecting the arctic is precession; this is a combination of the eccentricity of earth’s orbit (how much it differs from a perfect circle) and the time within the seasonal cycle at which we get closest to the sun. When we’re closest to the sun (“perihelion”) during midsummer, the arctic gets a roaring amount of summer solar energy, but when we’re furthest from the sun (“aphelion”) during midsummer, arctic summertime insolation is strongly muted. The precession factor was also in decline for about 10,000 years, although it bottomed out in the last few thousand years:
It’s worth noting that although precession strongly influences arctic sunlight during summer, it has no effect on the average throughout the entire year. It’s also worth noting that when the precession factor is high, the arctic gets more summertime solar heat but the antarctic gets less; precession affects the two poles oppositely. In contrast, obliquity affects the two poles in the same way, and also affects the annual average of incoming solar energy at the poles.
Astronomers have computed the relevant aspects of earth and its orbit (obliquity, eccentricity, precession) for millions of years in the past and future. From these data we can compute the amount of incoming solar energy at any given latitude for any day of the year. A common choice of latitude which is relevant to the growth and decay of ice sheets (and hence the progress of ice ages) is 65N. Here’s the insolation (incoming solar energy in Watts per square meter) at latitude 65N on midsummer day, from 10,000 BC to 4,000 AD (from 12,000 years ago to 2,000 years into the future):
Here’s the annual average insolation at latitude 65N:
We can likewise compute the midsummer-day insolation at the pole itself:
And here’s the annual average insolation at the pole:
The entire arctic has experience a decline in incoming solar energy, both on midsummer day and averaged throughout the year, since about 8,000 B.C. No wonder the arctic has been cooling!
If not for the greenhouse gases we’ve pumped into the atmosphere from burning fossil fuels, the arctic would still be cooling. But it’s not — it is most definitely warming. Fast. The yahoos who claim otherwise have only embarrassed themselves.
41 responses so far ↓
David B. Benson // September 8, 2009 at 1:48 am |
And the 65N insolation curve agrees fairly well with the GISP2 ice core temperatures for the last 10,000 years, althugh the temperature record is not so smooth.
Duh, imagine that!
Derecho64 // September 8, 2009 at 2:33 am |
Nice analysis. Some folks (i.e., Watts and apparently Pielke Sr.) don’t get it at all.
koen // September 8, 2009 at 7:26 am |
Tamino,
Can you explain why 90° figures are much higher than 65° figures at midsummer day, while their yearly average is lower? I would have expected energy at the pole always to be lower than at 65°.
[Response: On the contrary, on midsummer day the north pole receives more incoming sunlight than any other location on earth. This is because the sun is at a constant altitude in the sky for 24 hours continuously.]
Curious // September 8, 2009 at 7:37 am |
The difference in insolation is (logically) greater in summer (50 Vs 6 W/m2), so we have a greater negative forcing in summer than in winter. I guess that’s the reason why temperatures have increased specially in winter.
Nick Barnes // September 8, 2009 at 7:56 am |
I find it surprising that the insolation varies so little, given the dramatic effects of the cycles. Average annual polar insolation has only fallen a few Watts – 3% – in ten thousand years. Plot any of these graphs against anything in the AGW era (e.g. CO2 forcing) and you’ll get a flat line.
Sekerob // September 8, 2009 at 8:11 am |
I wonder if the strengthening of an Arctic Vortex as has been observed at the Antarctic is part of this. Is loss of Stratospheric Ozone a function of this?
Sekerob // September 8, 2009 at 8:15 am |
The first line should have read “Is there a strengthening of the AV as…”. It seems to have been fairly unidirectional at that uncharacteristically for a long period, plus last there was the Vortex splitting, drawing in warmer air from the south inbetween.
Gavin's Pussycat // September 8, 2009 at 1:52 pm |
Actually this explanation is a bit imprecise. Climatological precession is defined as the motion of the direction of the Earth axis relative to the direction of the line of apsides of the Earth’s orbit, i.e., the difference in rate between astronomical precession (in an inertial frame) and the rotation rate of the line of apsides.
Apart from that, also eccentricity itself varies as a separate phenomenon.
[Response: It's not the difference in rate, but the difference in angle between the ecliptic longitude of the pole and the line of apsides. And regarding that angle, the difference between astronomical precession (in an inertial frame) and the line of apsides actually is equivalent to the "time within the seasonal cycle at which we get closest to the sun."]
Phil Scadden // September 8, 2009 at 9:26 pm |
Nick Barnes. Indeed. And yet the correlation with climate cycles is compelling. How does such a small change in insolation produce such big changes in climate? Feedback. Orbital variations are a forcing, magnified by feedback – featuring our friend CO2 with others.
http://www.geos.ed.ac.uk/homes/tcrowley/crowley_Nature08_iceages.pdf
is an interesting paper using a very simple model.
Deech56 // September 8, 2009 at 10:34 pm |
Not sure if I should thank Tamino for providing a link to WTF, but I do think someone should give Joel Shore a medal for trying to talk sense.
Lucas // September 8, 2009 at 10:48 pm |
@Sekerob,
Check:
http://en.wikipedia.org/wiki/Ozone_depletion#Ozone_depletion_and_global_warming
TCO // September 8, 2009 at 10:48 pm |
So how about the Climate Audit stuff? Why waste time with the least sophisticated stuff? If you’re a math stud, isn’t it more interesting to deal with the smarter critics?
[Response: I don't put McIntyre in that category.]
Ray Ladbury // September 9, 2009 at 12:16 am |
TCO, given the high esteem you have so often expressed for McI et al. here and elsewhere, are ya’ really sure you want to tell us they’re the best the denialists have to offer?
Gavin's Pussycat // September 9, 2009 at 4:17 am |
Rate, angle, whatever… but eccentricity variations are not a part of climatological precession, right? You text is potentially misleading (clumsily formulated) in suggesting that it is.
TCO // September 9, 2009 at 5:20 am |
What category? It was a comparative, Tamino. You don’t think McI is smarter than Watts? You’ve made remarks in the past that he was. I mean, you can still rip his tits. But just rip something a little farther up the evolutionary ladder.
TCO // September 9, 2009 at 5:22 am |
Ray…if he sucks and he’s the best they can offer…you should still go after that…not the Ned Flanders like Watts. Now don’t make me slam you for your second rate grads school. I’m in the mood to scratch like a cat.
Philippe Chantreau // September 9, 2009 at 7:39 am |
Well, Ray, whether or not TCO says so, McFraudit IS the best that the denialosphere can muster. Better than Pielke Sr. How good that best is, that’s another question.
TCO // September 9, 2009 at 1:46 pm |
Zorita is cool…
Mark // September 9, 2009 at 2:32 pm |
“What category? It was a comparative, Tamino. You don’t think McI is smarter than Watts? ”
TCO, saying “he’s smarter than Watts” is damning with faint praise:
http://idioms.thefreedictionary.com/damned+with+faint+praise
Ray Ladbury // September 9, 2009 at 3:32 pm |
TCO, let me know when McI publishes something–or you, for that matter.
pough // September 9, 2009 at 4:33 pm |
In terms of intellect, I guess so. But not in terms of popularity. WTFIUWW was rated the best science blog. This sounds a lot like the arguments in other venues, where folks are taken to task for not dealing with the best arguments. Meanwhile, however, the bulk of the public has embraced the worst. Cutting away at the worst arguments leaves only the best to deal with. How is that a bad thing?
TCO // September 9, 2009 at 7:25 pm |
Ray, I’m not defending him. I’m saying that Tammy should go after the more interesting prey. Sheesh. I’m all over him to publish. Keep the hell up.
Philipe: agreed.
John Cross // September 9, 2009 at 7:27 pm |
I agree with Deech56! Joel is doing a great job on WUWT. He is polite and sticks to the point and makes his points very well. Some of the people who respond to him could do as well.
John
Gavin's Pussycat // September 9, 2009 at 7:29 pm |
Zorita publishes. Good stuff even.
YBW // September 9, 2009 at 8:29 pm |
It is sad to see name calling replacing logic in scientific discussions.
Dr. Pielke said that Kaufman et al. only reported data that supported Arctic warming and ignored data that did not.
In particular they point out that the Danish data does not support Arctic warming.
You have not refuted the claim.
The discussion of insolation is tangential at best. You seem to be saying: Even if temperatures are the same, they should be dropping because of decreasing insolation. An interesting point but it says nothing about Pielke’s claim.
I followed your link that shows data that the Arctic is warming. Very nicely presented. But again, not to the point.
You still need to explain why the data that does not support Arctic warming is faulty with emphasis on the Danish data set.
[Response: Pielke and Watts are claiming that temperatures in the Arctic are about the same as they were in 1958. I showed that's not true, which you describe as "Very nicely presented," but you say it's "not to the point." That's illogical.
As for the Danish data, neither Pielke nor Watts did any analysis of it -- none at all -- but still made claims about it. How logical is that? Watts just showed plots, then made the claim in spite of the fact that the graphs contradict him. How logical is that?
It so happens I've recently acquired the Danish data. Guess what? It flatly contradicts Watts and Pielke; even the data they refer to shows their claim is false.
What does logic lead you to conclude from that?]
YBW // September 10, 2009 at 1:37 pm |
First of all you didn’t show that their 1958 claim is untrue. You and Watts both present a graph and make a claim about it without doing any analysis. Sorry but the “my eyeball is better than your eyeball” argument is not analysis. Please do an integration of the difference from the average and compare. Of particular interest would be how the difference compares with variations in other years. You’re obviously good at statistics please do some Calculus.
Second, the 1958 data was presented as an example of a much larger claim: Kaufman is ignoring data that is contrary to his premise. I don’t see this premise rebutted. But maybe I missed something. Please point out the rebuttal so I can think about it.
Third, the fact that you analyzed the Danish data is encouraging. Could you post a link.
Finally, I very much appreciated your links to long term temperature data for the Arctic in the Yes, Virginia the … post. Can you post a link to a climate model that includes the warming from 1920 to 1960? Since insolation was decreasing, atmospheric carbon was no where near it’s current levels, and there doesn’t seem to be a correlation with the PDO, it seems like a reasonable test for a model.
On a different level, I would say that your discussion style seems modeled after that of Carlo Rubia (N.P. 1984). I suggest channeling Martin Deutsch (Discoverer of positronium.) I worked with both men while I was at MIT. Martin is the one people respected.
[Response: It's too bad that you're just being argumentative for its own sake. If you haven't seen enough to convince you that their 1958 claim is untrue then you need to check your cognitive skills.
It's also very telling that your first comment lamented insults over logic, but you just can't resist insulting me -- that "Martin is the one people respected" after comparing me to the other is a coward's way of saying I don't deserve respect. Clearly you're willing to use insults, but you haven't given us any logic. Pathetic hypocrisy.
As for using graphs, the ones I've shown are sufficiently clear that everybody (except the insane) can see that I haven't drawn the opposite conclusion to what the graphs actually indicate. Watts on the other hand draws a conclusion which is contradicted by his own graphs.
As for analysis, I've done that too and I'm not just making claims based on visual inspection. But this post is already long enough so I didn't want to include all that in a single post. I'll probably do a post on that too. What I won't do is dance to your music, linking and posting what you demand just because you're too obstinate to admit what's obvious to everybody.]
YBW // September 10, 2009 at 6:50 pm
[edit]
I’ve designed scientific instruments for 25 years, on four continents in the fields of particle physics, astronomy, protein and small molecule crystallography, and DNA and protein synthesis. I’ve worked for guys with Nobel Prizes and graduate students.
[Response: We are not impressed, except with the size of your ego.]
[edit]
My guess is that you get an adrenaline rush from being abusive.
[Response: Just like I said: you started out criticizing insult in favor of logic, but you're happy to insult me while offering no logic. Hypocrite.]
[edit]
drawp // September 9, 2009 at 9:04 pm |
Tamino,
Some fellow named Ian posted on CA “Kaufman and Up-side Down Mann” and accused Mann of fraud. Do you have any idea what is Ian’s last name?
bluegrue // September 9, 2009 at 9:05 pm |
Pielke seems to take a very narrow definition of “current”. If you do not look at annual data but only summer months he is “almost right” for certain values of “almost”. I calculated quick and dirty linear regression values for anomalies (base period 1960-1989) for the months of January and July over the period 1948 to 2009. The former results in about 0.9°C/decade, the July slope is “only” 0.1°C/decade. Since 2003 the July anomalies are about 1°C. That’s “close to the longer term average” – wonder oh wonder for above zero temperatures that are stabilized by the melting of the ice.
http://i31.tinypic.com/30bphye.png
Lorax // September 9, 2009 at 9:38 pm |
Pielke is out to lunch. The Danish data that they refer to are valid for north of 80 N, the Arctic circle is 66.5 N! The area north of 80N is almost completely void of land, and is almost entirely covered by sea ice, even when the sea ice is at its annual minimum. So these data are definitely not representative of conditions in the Arctic!
And he has the audacity to accuse others of using inappropriate data…..
William // September 9, 2009 at 11:10 pm |
I thought dirt was the reason the snow was melting up in the Artic in the first place. All that soot from India and China. More snow melt = less snow and less reflection of incoming light. Does that result in some kind of temperature increase? Also seems there is a lot of desert “dust” dust that may be settling there as well.
Thanks
William
Ray Ladbury // September 10, 2009 at 12:04 am |
TCO, what you–and McI, for that matter–fail to understand, is that his stuff is irrelevant. He finds little nits while ignoring mountains of evidence. If he had anything really worthwhile, someone else would publish it–suitably embellished–even if he didn’t. Science advances by doing science, not by “auditing”.
DrC // September 10, 2009 at 12:39 am |
Y’all should check out Peter Huybers stuff on orbital forcing. He’s gone a long way towards explaining the 100k paradox and integrated summer insolation forcing.
http://www.people.fas.harvard.edu/~phuybers/
[Response: I'm somewhat familiar with Huybers' work (only "somewhat") but I've found it extremely impressive, well worth detailed study.]
Mark // September 10, 2009 at 10:45 am |
“I thought dirt was the reason the snow was melting up in the Artic in the first place. All that soot from India and China. ”
So you don’t think that raising temperatures by about 4C would cause any melting whatsoever, William?
Curious // September 10, 2009 at 5:23 pm |
The summer graphs look like summer insolation has already reached (or is near to reach) a minimum, influenced by precession, but the annual average is still in decline, influenced by obliquity. Which one of them has a greater impact on temperatures (and sea ice)? I suppose that annual average is more important, isn’t it?
Thanks!
[Response: As far as I know (I'm not an expert) it's an open question. The usual approach to estimating the influence on ice sheet growth/decay is to use midsummer insolation, but before the mid-pleistocene transistion ice age cycles were ruled by obliquity which would argue for annual average. There's also the fact that olbiquity affects both poles in sync but precession affects the poles oppositely. I think Peter Huybers has argued for using something like net summertime heating.]
Martin Vermeer // September 10, 2009 at 6:26 pm |
YWB:
> Can you post a link to a climate model that includes the warming
> from 1920 to 1960? Since insolation was decreasing, atmospheric
> carbon was no where near it’s current levels, and there doesn’t
> seem to be a correlation with the PDO, it seems like a reasonable
> test for a model.
Dude, if you think that an effect like this which is significant over 2000 years will even show up over only 40 years, there is something wrong with your sense of proportions.
BTW I’m sure there are model outputs like what you’re looking for somewhere… why not acquire a useful skill and find them? Real scientists do it all the time…
Curious // September 10, 2009 at 6:30 pm |
Thanks for your answer, Tamino (and thanks for yet another great post). That’s curious, because I believe that these same orbital factors indicate that, without the human influence, the long-term cooling trend which began some 6000 years ago should continue for the next tens of thousands of years:
http://www.sciencemag.org/cgi/content/abstract/207/4434/943
Therefore, I would tend to think that precession and annual average insolation still has a remarkable influence (because the cooling trend is supposed to continue in spite of the upcoming increase in summer insolation).
[I'm far far far away from being an expert]
Curious // September 10, 2009 at 6:45 pm |
Typo: “When we’re closest to the sun (”perihelion”) during midsummer, the arctic gets a roaring amount of summer solar energy, but when we’re furthest from the sun (”aphelion”) during midsummer, arctic summertime insolation is strongly muted”
I suppose that one of those midsummer should be midwinter (or indicate what hemisphere is referred to in each case). I think that during the perihelion (closest to the sun) it is winter the northern hemisphere.
george // September 10, 2009 at 9:30 pm |
William says
You might find this helpful:
Aerosols May Drive a Significant Portion of Arctic Warming
04.08.09
Then again, I suppose Anthony Watts or Roger Pielke Sr might wish to change the above phrasing slightly:
Al Tekhasski // September 11, 2009 at 7:30 pm |
I wonder, since what time the climate begun to be characterized by conditions on one midsummer day only? I thought that the climate is based on a concept of “average”, isn’t it? How this local theory can “in fact” trigger ice ages if _in fact_ the global average insolation did not change more than 0.0053% over the discussed 12ky period? Should not this phrase with “in fact” replaced with “in theory”?
[Response: You're mighty confused.
Climate is not characterized by conditions on one midsummer day. But midsummer insolation at 65N latitude is a good indicator of how incoming sunlight is re-distributed from equatorial regions to polar ones, especially during the summer when ice sheet melting takes place. In fact a change of 50 W/m^2 is nothing to sneer at; its impact on ice sheets is dramatic.
Then there's the fact that ice age cycles show precisely the periodic behaviors of the obliquity and precession cycles, and have done so for at least the last 5 million years. Perhaps you think that's a coincidence?
But you're right about one thing: the temperature change between glacial and interglacial conditions (about 5-6 deg.C global average) cannot be accounted for by a tiny change in total insolation. It requires amplifying affects, due to the melting of ice sheets causing albedo feedback, and the release of CO2 causing greenhouse-gas warming.
That's the fact, jack.]
Al Tekhasski // September 11, 2009 at 9:38 pm |
How nice, thanks. Now, speaking about facts, did you say something about ice ages following precisely the periodic behaviors of astronomically accurate Milankovitch cycles? Perhaps you need to get re-acquainted with some serious literature. Look it up:
http://ocean.mit.edu/~cwunsch/papersonline/milankovitchqsr2004.pdf
“A number of records commonly described as showing control of climate change by Milankovitch insolation forcing are reexamined. The fraction of the record variance attributable to orbital changes never exceeds 20%. In no case, including a tuned core, do these forcing bands explain the overall behavior of the records. At zero order, all records are consistent with stochastic models of varying complexity with a small superimposed Milankovitch response, mainly in the obliquity band. Evidence cited to support the hypothesis that the 100 Ka glacial/interglacial cycles are controlled by the quasi-periodic insolation forcing is likely indistinguishable from chance”
[Response: Gosh, the 100 Ka cycles have nothing to do with obliquity or precession. Who didn't know that?
It's the 40 Ka and 23-19Ka cycles that are obliquity and precession, and even Wunsch acknowledges that they're a real part of the ice age signal.
You need to get re-acquainted with reality -- and with more current research. Start with Lisiecki & Raymo 2005, Paleoceanography, vol. 20, PA1003, and while you're at it, Clark et al. 2009, Science, 325, 710-714 doi:10.1126/science.1172873.]