# RealClimate

1. Hansen et al.’s New Climate Dice is another good way to demonstrate the growing problem. For a while last year I thought we were moving toward the UUA (Universal Unattributor Algorithm) that could slice and dice any bad climate consequences into small enough slices in time & space so that no one slice could be attributed to anything but bad luck. Hansen et al. look instead at the overall percent of the earth’s surface that is out of the norm by several sigma.

Comment by Pete Dunkelberg — 17 Jan 2012 @ 9:50 AM

2. I’d seen this before it is a wonderful cartoon.
I’d just assumed that:
man’s path = total ocean heat content
leash length = bounds on energy transfers
dog jiggles driven by ocean oscillations, solar jiggles, volcanoes …

left to his own devices, man would walk horizontally.
In this case, the dog is growing, wants to go to the upper right, and its average motion is pulling the man there.
Left to his own devices, man would go horizontally, more or less.

Comment by John Mashey — 17 Jan 2012 @ 11:29 AM

3. I don’t find the above analogy appropriate for the world’s longest temperature record.
http://www.vukcevic.talktalk.net/CET-100-150-100.htm

Comment by vukcevic — 17 Jan 2012 @ 12:58 PM

4. Vukcevic,
I don’t know–looks just like the paths my dogs take when they’re on leash. They might have chosen different breakpoints in their curve fit, though.

Comment by Ray Ladbury — 17 Jan 2012 @ 2:35 PM

5. Vukcevic #3, some CET info you might find enlightening:
http://rabett.blogspot.com/2010/07/this-is-where-eli-came-in.html

You never know where that dog has been.

Comment by CM — 17 Jan 2012 @ 2:52 PM

6. The leash length could perhaps represent the difference between inland and coastal climates.

The climate of Medecine Hat, AB, Canada obviously gives its dog more rope than that of Egg Island, BC, also in Canada.
http://www.climate-charts.com/Locations/c/CN71000010626460.php
http://www.climate-charts.com/Locations/c/CN71000010626460.php

By the way, Medecine Hat is a name that is hard to forget because of its hat like seasonal temperature graph. It is perhaps therefore it has become an textbook example of continental climate.

Comment by Per — 17 Jan 2012 @ 4:10 PM

7. Very interesting.

But would it exhibit similar behaviour to a dog not on a leash? In other words, can you prove that the dog is on a leash, rather than running free like the wind?

[Response:That possibly ranks as the stupidest comment I’ve seen here yet.–Jim]

Comment by Isotopious — 17 Jan 2012 @ 5:39 PM

8. It’s the white background that fools ya. Actually the dog is walking a straight line over a highly rumpled invisible grid surface, and the man is being towed along like a balloon at a fixed altitude (on a flat grid). So the length of the leash is a vector between a moving point on the invisible flat grid (across which the man is floating), to the invisible rumpled grid across which the dog is making a beeline. So to speak. Then you plot the periodicities in the behavior of the leash ….

Comment by Hank Roberts — 17 Jan 2012 @ 5:52 PM

9. #7–If you’re asking seriously, you’ve clearly never walked a dog.

Comment by Kevin McKinney — 17 Jan 2012 @ 6:05 PM

Science is no one’s lap dog, no institution however powerful can put it on a leash.

#5 CM
No name, no comment.

Comment by vukcevic — 17 Jan 2012 @ 6:16 PM

11. Sigh.
It is not that difficult an analogy.

The man’s path is the climate, or perhaps the total heat content from the deep ocean to the top of atmosphere. Without a forcing, it would be horizontal. It is trending up because there is a net forcing. CO2 is the prime forcing that is changing over the period of interest.

The dog does not affect the man’s path.

The wanderings of the dog represent either the year to year variations brought about all the other factors that affect the total heat content, shifts of heat content from areas where we can measure it well to areas where we can’t, or both.

The leash length is just the limit on how far off the main path actual variations or variations on our ability to measure. The longer the leash, the more time it takes to decipher which way the man is going. We can’t see the man, we can only see the dog.

Unfortunately Pete, the majority understands neither the concept of sigma (variance), nor how the selection of a baseline does not change the direction of a trend. It’s all too easy to decide that something doesn’t mean anything when you are not equipped to understand what it means.

Comment by Chris G — 17 Jan 2012 @ 6:28 PM

12. The analogy of the man and dog is a good one but assumes the man is following a particular path as Foster and Rahmstorf (F&R)implicitly did. F&R and only cover the period 1979 to 2010 and I wondered how it would look going back to 1950, the start of the MEI. In general my results are similar to theirs but the flatness of temperature before 1976 is to some extent enhanced.
http://climateopinions.blogspot.com/2012/01/short-term-variations-in-temperature.html

Comment by Ron Manley — 17 Jan 2012 @ 6:40 PM

13. “… not use the [CET] data before 1730 is clearly explained in the first paragraph of the 1992 Parker, Legg and Folland paper: Parker, D. E., T. P. Legg, and C. K. Folland, 1992: A new daily Central England Temperature Series, 1772-1991. Int J Climatol, 12, 317-342.

Comment by Hank Roberts — 17 Jan 2012 @ 7:26 PM

14. http://news.sciencemag.org/sciencenow/2012/01/global-warming-may-trigger-winte.html “… The team’s analyses suggest that climate cycles such as the El Niño-Southern Oscillation, the Pacific Decadal Oscillation, and the Atlantic multidecadal oscillation can’t explain the regional cooling trends seen in the Northern Hemisphere during the past couple of decades as well as trends in Siberian snow cover do.”

Comment by Hank Roberts — 17 Jan 2012 @ 7:52 PM

15. #9 vukcevic

Your response actually doesn’t make sense. Also your inability to see that natural variability occurs on climate path based on the radiative forcing illustrates your basic misunderstanding of these realities.

That in turn may indicate you basically don’t understand the difference between climate, natural variability, weather, and of course human influenced climate forcing.

Comment by John P. Reisman (OSS Foundation) — 17 Jan 2012 @ 8:14 PM

16. Kevin McKinney,

Let’s not get pedantic. A dog that is simply sniffing and walking around without a lead is not that farfetched….a random walk I believe, with the ‘climate trend’ simply being the product of a series of random events. As I said, prove that it is the other way round, with the weather being constrained by the climate.

[Response:It’s called “attribution”, the evaluation of relative strengths of evidence of competing explanatory mechanisms: a hallmark of science. Check it out sometime.–Jim]

Climate is after all just an average of the weather. The argument is circular. You can’t get a climate trend without mathturbating weather data.

[Response: Man are you ever confused.]

The climate is a product of the weather. Maybe you should try and get weather data out of a trend line (good luck with that one).

Comment by Isotopious — 17 Jan 2012 @ 8:41 PM

17. Hank Roberts: “Actually the dog is walking a straight line over a highly rumpled invisible grid surface, and the man is being towed along like a balloon at a fixed altitude (on a flat grid).” , a bit like a fish towing a boat, giving it more line allows it to make larger swings with maybe faster speed, if the line is cut we’ll have a runaway…

Comment by jyyh — 17 Jan 2012 @ 11:18 PM

18. #16 Isotopious

The climate is a product of the weather. Maybe you should try and get weather data out of a trend line (good luck with that one).

First, the argument is not circular.
Second, your statement is what I would have to call an illogical fallacy. And in this case two negatives do not produce a positive.

Confused is the nicest description for your statements though.

The climate is ‘not’ a product of the weather, the weather is what happens due to climatic conditions and is much more chaotic than the conditions themselves. At the same time, weather measured over longer periods can produce trends attributable to climate.

Said another way, knowing climate forcing allows you to predict climate trends while specific weather predictions remain unpredictable over longer periods of time.

Without knowing climate forcing parameters, you can neither predict weather or climate.

It just doesn’t work the way you might wish to think it works.

Comment by John P. Reisman (OSS Foundation) — 17 Jan 2012 @ 11:50 PM

19. > a bit like a fish towing a boat,

The Old Man and the Sea Serpent?

Or perhaps we’re following the tracks of
Dr. Broeker and the Angry Beast.

Comment by Hank Roberts — 18 Jan 2012 @ 12:30 AM

20. Isotopius: Saying that climate is the average of weather is like not being able to find the forest because of all the trees that are in the way.

Comment by Craig Nazor — 18 Jan 2012 @ 2:28 AM

21. Isotopious says:

“But would it exhibit similar behaviour to a dog not on a leash? In other words, can you prove that the dog is on a leash, rather than running free like the wind?”

[Response:That possibly ranks as the stupidest comment I’ve seen here yet.–Jim]

Actually, I had a dog that would stay within a fairly close distance of me on long walks in the woods without a leash. Of course, one could say there was a psychological leash (loyalty) since the dog went where I went, not the other way around, at least most of the time. Occasionally, the dog would lead me to interesting (at least what a dog considers interesting) discoveries, but in the end it was the course I wanted to take that we took. So, back to the analogy, I think the climate to weather leash is more like the psychological leash, a bit more flexible than your ordinary leash. In some places weather has a large deviation whereas in other places less so. The important thing, however, is the path the man is following. Unfortunately we can only see the path that has his tracks in it (fresh snow I suppose), so yes we can track trends and deduce where we think the man is heading BUT if we’ve taken to short a span we may miss that the man is actually walking in a big circle, like me and my dog would, so we would end up back home at just about supper time. The supposition that his path “should” be horizontal is basically just a guess. We could calculate where the path “should” be under the snow to predict where the man is going if we know the major influences in path position i.e. is the man just walking in the woods with the objective of ending up where he started, or is going from point “A” to point “B”, or maybe he’s searching for something, or perhaps evading something; critical knowledge for determining the path of the man by calculation. So, statistics or physics, which produces the better prediction? It really depends on how much we know about the path (past or purpose) not the dog or the man.

Comment by John West — 18 Jan 2012 @ 2:44 AM

22. Since my posting last night, I’ve had a quick look at whether knowing where the owner wants to take the dog (i.e. assuming an underlying temperature trend) has any influence on where they both end up (i.e. the adjusted temperture record). The answer is that it does appear to.
http://www.climatedata.info/Discussions/Discussions/opinions.php

Comment by Ron Manley — 18 Jan 2012 @ 4:28 AM

23. John West says:
“So, statistics or physics, which produces the better prediction? It really depends on how much we know about the path (past or purpose) not the dog or the man.”

I have to disagree with myself in the event of a novel situation. Supposing we know the man walks his dog in a large circle every day and we know the purpose is to walk for an hour and end up back where he started and we also know the terrain constraints to a high degree of accuracy. The historical path or the calculated path would be equally predictive until he came across something that he had never encountered before. Let’s say a bear (industrial revolution). Now we have to know more about the bear for any hope of prediction. Is it a big bear, little bear, polar bear, teddy bear, Buddy Bear, grizzly bear, Care Bear, cuddly bear, etc? The past path may be irrelevant. The past purpose may be irrelevant. The terrain constraints may come in handy though, but we still have to figure out what the man’s new purpose is or even if there is a new purpose. If it’s just a teddy bear the dog might stretch the leash a little for a sniff or two but hardly alter the path at all, while a grizzly bear might compel the man to completely abandon the path and assume a new purpose (not get eaten). So, now the knowledge of the path (past or purpose) is nearly useless except for the terrain constraints portion. Now, only the calculation approach has any hope of being predictive unless the bear is “insignificant bear” and it’s predictive value really depends on knowing a lot about the bear, the man (what’s he likely to do), the dog (bear dog?), and the terrain.

Comment by John West — 18 Jan 2012 @ 4:59 AM

24. #15 John P. Reisman says:
vukcevic you basically don’t understand the difference between climate, natural variability, weather, and of course human influenced climate forcing.
Hi John, an all-inclusive assessment. I wouldn’t dare argue with any of it.

Comment by vukcevic — 18 Jan 2012 @ 7:54 AM

25. JP Reisman #18
It is possible to predict the weather with reasonable skill without knowing anything about climate or its forcing parameters

Comment by FundMe — 18 Jan 2012 @ 8:12 AM

26. Isotopious, I have but one word to say to you:

Squirrel!

Comment by Ray Ladbury — 18 Jan 2012 @ 8:30 AM

27. #16–I rest my case.

Comment by Kevin McKinney — 18 Jan 2012 @ 8:59 AM

28. Weather is one roll of the dice.
Climate is winning a few rolls of the dice, but losing your shirt in the long run.

Comment by Brian Dodge — 18 Jan 2012 @ 10:12 AM

29. To say that “climate is a product of weather” (isotopious, #16) is like saying that the current in a river is the product of the swirling eddies observed in the stream.

Comment by Jerry Steffens — 18 Jan 2012 @ 12:22 PM

30. #21 John West

Ever try to train a weather pattern ;)

#25 FundMe

Weather is reasonably predictable in a span of about 10 days and then the error potential gets out of hand. Long term climate based on radiative forcing is predicable on long time scales depending on the confluence parameters. That means monthly, seasonally, yearly, intra-decadal, inter-decadal, century, millennial.

#29 Jerry Steffens

Excellent analogy.

Comment by John P. Reisman (OSS Foundation) — 18 Jan 2012 @ 12:35 PM

31. While auguring about dog walking is lots of fun, the important point with Hans Rosling’s Fun with Stats is that people that understand statistics need to be able to present them in a way that is obvious to middleschoolers. I know a number of people who don’t even think statistics apply to anyone, much less themselves (I’m a careful driver, I don’t need a seat belt. Not everyone gets lung cancer.)
Presenting statistics in a fun and informative way is a necessity for a political climate that spends its time denying video tapes of what happened yesterday.

Comment by eric — 18 Jan 2012 @ 1:14 PM

32. “29.To say that “climate is a product of weather” (isotopious, #16) is like saying that the current in a river is the product of the swirling eddies observed in the stream.”

Well, no. It’s more analagous to the notion that climate is the current and weather is the direction of the water molecules. You can’t separate them. Ultimately, climate is a product of the measurement of weather across a large distance over a period of time. The river isn’t an ideal metaphor for climate because, historically, climate has not held to a rigid path.

Comment by SirCharge — 18 Jan 2012 @ 1:25 PM

33. SirCharge: “The river isn’t an ideal metaphor for climate because, historically, climate has not held to a rigid path.”

Nor does a river.

Comment by Ray Ladbury — 18 Jan 2012 @ 2:27 PM

34. Nice video, seems that it has gone near viral?

Reminds me of Murray’s “A drunk and her dog”, where he explains the concept of cointegration and random walk using the example of a dog and a drunk. http://akson.sgh.waw.pl/~kp38166/lab.%209/Murray93DrunkAndDog.pdf

Comment by Bart Verheggen — 18 Jan 2012 @ 4:05 PM

35. Isotopious, perhaps we need a new rule of thumb: Definition is not causation.

True, climate is sometimes defined as a thirty year average & variance of weather. (With a monotonic forcing, this gives you the climate of the past). But it isn’t purely self-caused like a perpetual motion machine. Weather / climate is what happens as the energy from the sun passes through our environment before going on its way through space.

The concept of “climate system” may be helpful here. The climate system is all the main physical parameters which together with physics and chemistry cause weather and its average & variance.

Comment by Pete Dunkelberg — 18 Jan 2012 @ 4:22 PM

36. “Nor does a river.”

That’s a bit pedantic, but… Yes, rivers paths vary, but their directions change extremely infrequently, whereas the temperature anomaly has changed signs quite often, historically. Climate changes on a decadal scale whereas rivers change directions over eras related to elevation changes and glaciation. Thanks for correcting me, although I still contend that it was a poor metaphor.

Comment by SirCharge — 18 Jan 2012 @ 11:10 PM

37. All the talk of dog’s or any other creature’s random walk (leash or no leash) having analogy with the global temperature is at the best misleading.
Global temperature short term oscillations (GISS Land and Land&Ocean) closely follow the AMO oscillations.
http://www.vukcevic.talktalk.net/GISS-spec.htm
There are many articles on the AMO, you can start with Dr. Mann’s article on the subject.

Comment by vukcevic — 19 Jan 2012 @ 6:00 AM

38. #36 SirCharge

It’s just an analogy, it doesn’t have to be perfect. I could come up with a hundred analogies, none would be perfect.

– A girl walking in a mall wants to get to Nordstroms, but there are many shops along the way and her short term path varies on her way to her expected destination.

– A guy is dating a girl, but he is distracted by many other attractive women in bikinis.

– A college student is interested in becoming a doctor, but also takes other elective courses that are interesting but not on the medical curriculum path.

– A dog is walking along on a leash and likes to chase ducks, but there are many squirrels that are distracting him…

Maybe you are being just a tad picayune?

Comment by John P. Reisman (OSS Foundation) — 19 Jan 2012 @ 11:09 AM

39. #37 vukcevic

Actually, it’s at worst misleading. It is at best reasonably descriptive analogically to the difference between long term natural cycle and short term natural variation.

As to your AMO picture (without any claim) you still have not made a case for whether or not the chicken or the egg came first. And you have not demonstrated the significance of the correlation to changes in total radiative forcing in temperature.

Please do that first. Write and submit your paper to a qualified peer review.

I myself am a skeptic. As a general rule, I don’t buy into an assumption such as yours without much more analysis, peer review, and in many cases, peer response.

Saying hey, look a cloud over there, and look, another cloud over there. They are both white so they must be related just doesn’t cut it as a valid scientific thesis.

Comment by John P. Reisman (OSS Foundation) — 19 Jan 2012 @ 11:15 AM

40. #39 John P. Reisman says:
difference between long term natural cycle and short term natural variation.
long term natural cycle:
http://www.vukcevic.talktalk.net/CET-NVa.htm
short term natural variation:
http://www.vukcevic.talktalk.net/GISS-spec.htm
random walk is just a copout, nature is ruled by the cause-consequence relationships, it is within our capacity to understand, we are on the way, but not there yet.

Comment by vukcevic — 19 Jan 2012 @ 2:13 PM

41. # 40 vukcevic

The limits to your view are profound. Most examining climate see long term natural cycles on larger scales more like the 100,000 year ice age cycles (and that is what I am referring to):

Of course you can extend that outward and view climate from on tectonic impact scales as well.

But as always, context is key.

Comment by John P. Reisman (OSS Foundation) — 19 Jan 2012 @ 2:59 PM

42. #40 vukcevic

Are you sure your name isn’t Newt, or some other familiar political name? You come across as a politician constantly spinning every pedantic point to your favor without addressing the bigger picture.

The illustration of the dog varying the path still stands. Just because ‘you’ don’t understand why the dog is varying his path, does not mean that the dog doesn’t have a reason in the construct of cause and effect.

Comment by John P. Reisman (OSS Foundation) — 19 Jan 2012 @ 3:08 PM

43. #40 vukcevic

To clarify the issue, what you are showing in your charts is one of the dogs wandering around.

The long term path of climate is dictated by the Milankovitch cycles

http://ossfoundation.us/projects/environment/global-warming/milankovitch-cycles

Comment by John P. Reisman (OSS Foundation) — 19 Jan 2012 @ 6:45 PM

44. The The location of the man is time(horizontal), and net average energy exchange with the rest of the universe(vertical). The reason his path goes up is because GHGs are going up. His path should curve upward soon because of strong feed-backs, like albedo reduction and arctic methane and CO2 release from permafrost.

Comment by Vergent — 21 Jan 2012 @ 3:16 PM

45. 40 vuk said, “random walk is just a copout, nature is ruled by the cause-consequence relationships, it is within our capacity to understand, we are on the way, but not there yet.”

No, random walk is primarily about chaos, which by definition can’t be understood via cause-consequence. It is why weather will never be forecast even marginally well five years in advance, yet climate can theoretically be forecast with great accuracy centuries in advance (with the caveat of volcanoes, changes in human activities, evolution, and other events not input to the forecast)

The big problem with this post’s analogy is the leash. A dog on a leash will spend almost all of its time at the end of the leash. (either that or at heel, which removes the random walk completely) A much better analogy would be to lose the leash, replacing it with a condition on the dog that it by choice never runs away. The dog will roam close or far, but always centered on the purposeful walk of the person. Of course, even this is imperfect as the dog’s location relative to the person is not actually random, but determined by the desires of the dog. It will sniff trees and other things interesting to a dog, so a smart observer could predict the dog’s path far better than a meteorologist could predict the weather five years hence. ie, five years from now the dog will likely run ahead of the person as they approach the tree, will remain there as the person passes, and will only leave the tree when the person is far enough ahead to trigger the dog to continue on. This is being really picky, and destroying/not getting the analogy on purpose. Far better is to understand the lesson of the analogy – which is that climate moves along steadily and predictably while weather bounces and stretches randomly around the central tendency described by climate and season.

Comment by RichardC — 21 Jan 2012 @ 8:26 PM

46. > The dog will roam close or far, but always
> centered on the purposeful walk of the person.

As the drunkard keeps returning to the lamppost.

Dunno, looks more to me like the path walking the dog along the seashore as the tide is rising.

Comment by Hank Roberts — 21 Jan 2012 @ 9:13 PM

47. DotEarth has a new post about weather and climate. I’m not sure, but it looks to be the usual problem therein. Commenters to counter the phony skeptics please (not to mention the false balance in the article itself, if I read it correctly)?
http://dotearth.blogs.nytimes.com/2012/01/21/tallying-disasters-and-gauging-global-warming

Comment by Susan Anderson — 21 Jan 2012 @ 10:45 PM

48. “A dog on a leash will spend almost all of its time at the end of the leash.”

Not if you use an extending leash, as I usually do; you’re always letting out and taking in (though this depends somewhat upon the dog–they are not all the same.)

All of which is a long-winded way of saying that I think we’re seriously wearing out this analogy!

Actually, there’s a meta-analogy here: just as the primary analogy tells us that short-term variation is basically distraction, minute examination of the details of that analogy exemplify another kind of distraction. After all, the analogy is not a reliable guide to the properties of the phenomenon of warming–just an imaginative teaching tool focussing on one of its aspects. Though I suppose it can be a fun parlor game to try to make it as exact and as all-embracing as it can possibly be modified to be.

Still, the finger is not the moon.

Comment by Kevin McKinney — 22 Jan 2012 @ 8:38 AM

49. Re. 45 Richard C

How about one of those retractable leashes? How far the dog (the weather) can wander is determined by the owner (the climate), but it’s a relationship where the owner will be aware of how far the dog wants to wander and dynamically adjusts the length. However, if the dog is having its food spiked with CO2 steroids it will become stronger and more temperamental, and prone to pulling the leash more to its limits.

Comment by J Bowers — 22 Jan 2012 @ 8:48 AM

50. Here’s another analogy:

Sometimes barking at the moon makes you feel like your doing something…

but it may also be irritating the neighbors.

Comment by John P. Reisman (OSS Foundation) — 22 Jan 2012 @ 12:58 PM

51. #50–“Sometimes barking at the moon makes you feel like your doing something…

but it may also be irritating the neighbors.”

Hence the (mostly British) expression “barking mad.” (OK, maybe not.)

Comment by Kevin McKinney — 22 Jan 2012 @ 1:33 PM

52. It’s a fair analogy. Reality is that global temperature varies +/- 4C from the mean, and has since at least 1900, and the deviation of monthly temperature from the mean fits a normal bell-curve distribution (i.e. seemingly random variation).

The interesting part is that the mean isn’t tracking greenhouse gases exactly. Relative to CO2 concentration, the mean took a trip to the cold side between 1900 and 1920, and deviated to the warm side in 1935 to 1946. The “dog” in that case was still wandering around the “man”, limited by the same length of the leash, but during those time periods the “man” was himself wandering away from the greenhouse gas drivers.

Anybody know what explains those deviations from the GHG driver?

Comment by Jbar — 23 Jan 2012 @ 10:33 AM

53. Well, Foster & Rahmstorf (2011) didn’t directly address the record before 1979, and so doesn’t apply directly to your question, jbar.

But over the period which they did examine, ENSO, TSI and aerosol loading accounted for most of the difference between ‘dog and man.’ It seems likely that those three factors would also have been a big part of the picture during the times you mention. (And I know there is quite a bit of literature examining the questions.)

Foster & Rahmstorf (2011) summarized:

http://tamino.wordpress.com/2011/12/06/the-real-global-warming-signal/

Comment by Kevin McKinney — 23 Jan 2012 @ 12:26 PM

54. # 50 & #51
Dr. Mann’s article was helpful in identifying what appear to be the source of the AMO, one of the most important natural temperature oscillations:
http://www.vukcevic.talktalk.net/AMOatSource.htm
perhaps reading Dr. Mann may be more useful than impersonating Statler and Waldorf

Comment by vukcevic — 23 Jan 2012 @ 1:14 PM

55. > isn’t tracking greenhouse gases exactly

‘exactly’

This is a talking-poing strawman argument that’s been rebunked recently.
Who’s pushing it these days?

Comment by Hank Roberts — 23 Jan 2012 @ 2:33 PM

56. #55–“. . .perhaps reading Dr. Mann may be more useful than impersonating Statler and Waldorf. . .”

Or perhaps not? The limiting factor, after all, is not the potential usefulness of the former. . .

Besides, I flatter myself that I do Statler and Waldorf rather well.

Comment by Kevin McKinney — 23 Jan 2012 @ 3:07 PM

57. Jbar,
Hmmm, 1900-1920, 20 years; 1935-1946…11 years. Climate-a trend of 30 years or longer. I think I see your problem.

Comment by Ray Ladbury — 23 Jan 2012 @ 3:53 PM

58. Ray,
Using your 30-year designations with the GISS global data yields the following deviations from the long-term trend line: +0.06C prior to 1896, -0.02C from 1896-1925, +0.01C between 1926 and 1955, -0.10C from 1956-1985, and +0.07 since. Regardless of the timeframe chosen, there are real deviations from the trendline. The dog is not totally random in his walk, but deviating over regular intervals. Maybe there is an oak tree on opposite sides of the street every other block (to reference your earlier analogy).

Comment by Dan H. — 25 Jan 2012 @ 7:33 AM

59. #58 Dan H.

What part of ‘it’s an analogy’ didn’t you understand?

In the real world shorter-term natural variation is dictated by oceanic heat content overturn along with solar variation. There are no oak trees.

If I am understanding you correctly, it seems your comment is hypocritical because it looks like you are attempting to mix a fantasy analogy of ‘oak trees’ with real world data and variation, while apparently simultaneously attacking by inferring analogies are weak because they are not real based on ‘your view’ of random vs. regular intervals.

Looks like another pot meet kettle moment. It looks like you need to study attribution and ocean cycles though.

http://ossfoundation.us/projects/environment/global-warming/current-climate-conditions/oceans

and do look into google scholar.

Comment by John P. Reisman (OSS Foundation) — 25 Jan 2012 @ 3:48 PM

60. John,

The oak tree analogy was in reference to Ray’s squirrel analogy. You may have missed that.

I fully understand that the variations correspond to ocean cycles.

Comment by Dan H. — 25 Jan 2012 @ 4:50 PM

61. #60 Dan H.

Okay, let’s play. What’s your position on human induced global warming?

Comment by John P. Reisman (OSS Foundation) — 25 Jan 2012 @ 8:50 PM

62. John,
Humans have been responsible for at least half of the observed warming since 1880. I expect future trends to mimic those of the past.

Comment by Dan H. — 26 Jan 2012 @ 8:42 AM

63. #62 Dan H.

How will the future trend mimic that of the past if humankind has increased the radiative forcing. Solar variation tends to be around 0.1 W/m2 and human induced positive forcing is 1.66 W/m2 (IPCC AR4 WG1) 1.8 (NASA)?

Or are you saying while we continue warming (natural cycle would have us relatively flat to cooling), natural variation will continue to meander like the dog analogy along the new warming path?

Comment by John P. Reisman (OSS Foundation) — 26 Jan 2012 @ 12:30 PM

64. Dan H is just posting a talking point there.

Try an expert assessment:
“somewhere between 80 to 120% of the warming.”

You know how to look it up.

Comment by Hank Roberts — 26 Jan 2012 @ 3:06 PM

65. John,
Basically, yes.

Comment by Dan H. — 27 Jan 2012 @ 12:12 PM

66. No random dog walk in the Atlantic hurricane activity, as usual there is a cause and the consequence.
According to the NOAA’s assessment the Atlantic hurricane activity is directly related to the Equatorial Atlantic’s SST; neither of which is predictable.
However that not may be the case.
Comparing the NOAA’s Atlantic Accumulated Cyclone Energy (ACE) index with the ‘Atlantic Hurricane probability index’ based on the North Atlantic other historical data (also available from the NOAA) it could be concluded that the hurricane activity will (on average) stay just above the normal for at least a decade.
http://www.vukcevic.talktalk.net/AHA.htm

Comment by vukcevic — 30 Jan 2012 @ 6:06 AM

67. Over what time period is it meaningful to talk about climate changes? Or put another way, how many years would it be necessary to average out the effects of natural variation (say we assume natural variation causes the global average temperature to vary in a gaussian pattern around the climate trend).

[Response: It depends on the forcings and the climate metric you are looking at. For the current situation, you need between 15 and 20 years for the global mean temperatures, a little less for Arctic minimum sea ice extent, a lot more for a local or regional temperature signal. – gavin]

Comment by DS — 30 Jan 2012 @ 3:56 PM

68. Thanks Gavin–I really appreciate you and the others helping me learn more about this stuff. Do you deduce the minimum time from looking at the data (like a 15 year filter seems to produce a smooth trend), or is this known from, say, that relevant short term climate oscillations tend to be less than 15-20 years?

Comment by DS — 31 Jan 2012 @ 2:01 PM

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