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Post by socold on May 25, 2009 17:15:02 GMT
"the PDO remains in a multidecadal negative phase, as it did from 1946-76, do you believe that will effect temperature trends for the next 20-30 years?" No because the PDO is a particular pattern of temperature anomolies, it isn't a cause of temperature change, it's more of an effect. PDO is already about as low as it can go and so all this particular effect is already seen on the global temperature record. Cause or effect, there is strong evidence that -PDO phases are associated with slight cooling or flat global temperatures. It's largely tautology. The PDO phases are not independant of the global temperature trend because the metric is derived partly from pacific SST anomolies.
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Post by tacoman25 on May 25, 2009 19:07:03 GMT
Cause or effect, there is strong evidence that -PDO phases are associated with slight cooling or flat global temperatures. It's largely tautology. The PDO phases are not independant of the global temperature trend because the metric is derived partly from pacific SST anomolies. Of course. But you still avoid the question...do you think that if this -PDO period persists as the last one did (1946-76), we will not see flat or slightly declining temps this time around? You made the statement that you expect global temperatures to resume rising again soon...no matter what. So logically, I have to assume that you don't believe the PDO/Pacific pattern phase will be a real factor?
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Post by socold on May 25, 2009 21:40:30 GMT
It's largely tautology. The PDO phases are not independant of the global temperature trend because the metric is derived partly from pacific SST anomolies. Of course. But you still avoid the question...do you think that if this -PDO period persists as the last one did (1946-76), we will not see flat or slightly declining temps this time around? No
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Post by tacoman25 on May 26, 2009 2:04:05 GMT
Of course. But you still avoid the question...do you think that if this -PDO period persists as the last one did (1946-76), we will not see flat or slightly declining temps this time around? No Ok, thank you. Any particular reasoning behind this belief?
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Post by woodstove on May 26, 2009 16:00:10 GMT
While you're at it socold, where do you see the Atlantic Multidecadal Oscillation headed? For instance, do you maintain that it will not return to significantly negative territory again (-0.25 to -0.40, let's say)?
Do you maintain that if it does go that negative there be no effect on global mean temperature?
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Post by hilbert on Jun 2, 2009 1:20:36 GMT
It will be interesting, I think, to see the US unemployment numbers for May, and how they fit on the graph on the first posting in this thread.
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Post by hilbert on Jun 3, 2009 11:46:24 GMT
I was browsing RealClimate, and it appears that they still believe in the hockey stick--can that be correct?
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Post by steve on Jun 3, 2009 12:58:20 GMT
While you're at it socold, where do you see the Atlantic Multidecadal Oscillation headed? For instance, do you maintain that it will not return to significantly negative territory again (-0.25 to -0.40, let's say)? Do you maintain that if it does go that negative there be no effect on global mean temperature? I, and I think socold, think that the various modes are just a part of climate variability that means that the wiggles in the global mean temperature anomaly are potentially partly explainable by the variations in the climate modes. That is, a strong El Niño will give warmer temperatures and conversely, the warmer temperatures can be explained by the strong El Niño rather than as part of the greenhouse gas induced warming trend. I don't think anyone "maintains" that changes in these modes have no effect on the temperature. While understanding the full effect on the climate of these oscillations is incomplete, there is little evidence to suggest that they impact long term trends (by long term, I mean more than the typical period of the oscillation).
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Post by icefisher on Jun 3, 2009 19:29:47 GMT
While understanding the full effect on the climate of these oscillations is incomplete, there is little evidence to suggest that they impact long term trends (by long term, I mean more than the typical period of the oscillation). LOL! They sure as heck do affect the long term trend when by trend you mean the estimated trend of a model that did not adequately account for them. Don Easterbrook's work overlays the affects of these oscillations that were unaccounted for by the IPCC and viola 60% of the projected warming just evaporates into the thin air. Thats pretty serious especially since the feedbacks that were supposed to triple the warming hasn't shown up. Ultimately when you do the math warming is chugging along but at a rate about one sixth the rate of what was originally predicted. Thats what happens when you parameterize your models on the up leg of one of those oscillations combined with a wrong guess on feedbacks.
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Post by icefisher on Jun 4, 2009 4:34:16 GMT
I don't think anyone "maintains" that changes in these modes have no effect on the temperature. Yeah take a look here to see how the system is operating with the oscillations:
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Post by steve on Jun 4, 2009 12:21:38 GMT
I don't think anyone "maintains" that changes in these modes have no effect on the temperature. Yeah take a look here to see how the system is operating with the oscillations: Do you find that plot convincing, icefisher?
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Post by icefisher on Jun 4, 2009 17:07:43 GMT
Yeah take a look here to see how the system is operating with the oscillations: Do you find that plot convincing, icefisher? It does seem to reflect what has been happening including various predictions that have been made along with a little dot between them for where we are now. What is there to complain about? This plot was created by an acknowledged and celebrated physicist and I see no glaring inaccuracies regarding it. Do you?
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Post by steve on Jun 4, 2009 17:51:08 GMT
I'm disappointed that you couldn't show your balance and common sense by offering an honest critique. As I have said before, no scientist's opinion should be taken on faith alone.
1. What is the physical justifcation for assuming a trend with a constant change in temperature with time? There isn't one. 2. Leaving aside the difference between a prediction and projection, is the IPCC projection accurately presented? I don't think it has. 3. What is the source of the obs data? It looks a bit like GISTEMP, except for the last two years. Is it being represented accurately? 4. Can the assumption of cooler back before 1880 be justified? HadCRUT3 would say not, so what is the justification for ignoring HadCRUT3?
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Post by socold on Jun 4, 2009 18:42:21 GMT
So when does "recovery from the little ice age" end? 2100? 2200? 2600?
...1950?
If we assume a linear background warming trend we get a linear future warming trend. Amazing how that works.
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Post by icefisher on Jun 4, 2009 19:00:49 GMT
I'm disappointed that you couldn't show your balance and common sense by offering an honest critique. As I have said before, no scientist's opinion should be taken on faith alone. 1. What is the physical justifcation for assuming a trend with a constant change in temperature with time? There isn't one. I suppose that means we will never ever again see you draw a linear trend line ever again, nor ever splice data sets to get a single trend line, nor pick the proxy that fits your argument huh? Indeed there can be problems with straightening out lines but the lines drawn here look a lot like that hockey stick did. 2. Leaving aside the difference between a prediction and projection, is the IPCC projection accurately presented? I don't think it has. It looks like the IPCC projections I have always seen. Perhaps you could reference something different. 3. What is the source of the obs data? It looks a bit like GISTEMP, except for the last two years. Is it being represented accurately? The file supporting this is 50 megs and available here. I haven't downloaded it to check references but you are certainly welcome to. people.iarc.uaf.edu/~sakasofu/4. Can the assumption of cooler back before 1880 be justified? HadCRUT3 would say not, so what is the justification for ignoring HadCRUT3? Hadcrut3 doesn't say that. If you recognize the pattern of the oscillations. . . .in fact it fits rather nicely. I have it plotted in Excel and there is no significant deviation from that line. I get .7 degrees for 150 years.
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