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Since
I am a bit late on this, you have probably already seen the stories
from NASA that apparently the Pacific Decadal Occilation, which
switches from warm to cool cycles every thirty to forty years, has just
switched from warm to cool.
The Pacific Decadal Oscillation (PDO) is a temperature pattern in the Pacific Ocean that spends roughly 20-30 years in the cool phase or the warm phase.
In 1905, PDO switched to a warm phase.
In 1946, PDO switched to a cool phase.
In 1977, PDO switched to a warm phase.
In 1998, PDO showed a few cool years.
In 2008, PDO seems to be switching to a cool phase. (NASA).
The
warm (cool) phase is determined by above-the-average
(below-the-average) temperatures along the West Coast of the U.S. and
Canada.
At the same time, a longer cycle occilation in the Atlantic called the AMO may also be in the cooling part of its occilation over the next decades.
Though from what I read, the PDO mainly affects
temperatures around the Pacific Rim, the Pacific is in fact a very
large part of the earth, so I wondered if its cylcling might have some
correlation with world temperatures:
Well, that is kind of interesting. Note by the way I use
the GISS surface data in this chart, so one can assume the warming in
the last 20 years is overstated for a variety of reasons we have discussed on this site. Never-the-less, it is interesting. A few thoughts:
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Catastrophists are spinning that the PDO cool
cycles just delay or suppress man-made warming signals. OK. But if
you argue this, you have to also argue for the converse -- that the PDO
exaggerate what might be man-made warming signals during its warm
cycles. Catastrophists and in particular the IPCC, however, said that all
of the post 1977 warming was due to man - I don't remember anyone
mentioning "PDO" in these discussions (In fact, they argue that some
additional warming was being masked). Catastrophists love to point to
natural cycles only when they can be claimed to mask man-made warming.
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I am constantly amazed at how much the 1905-1947 trend on this
chart looks like the 1977-2005 trend. But here is the amazing thing to
me: Catastrophists as well as the IPCC claim that these trends had
different causes. In fact, you MUST believe they had
different causes to believe the AGW story (since there was little
man-made CO2 in the first period). In other words, to belive the
catastrophic man-made global warming theory, you have to believe some
effect, presumably natural but never identified by the IPCC, drove
temperatures through 1947 and then switched off, never to return, at
the exact same moment that man began producing CO2 in earnest.
Update: It may be too early to tell if the PDO is doing a major or sort of minor shift, but the past frequency seems to indicate we will see a shift soon. Source
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