Re: For Slowman's Annoyance of the Day...

In article <rqcem41k44esipqaof6j2s9ru9v0edgrpd@xxxxxxx>, Raveninghorde wrote:
On Fri, 9 Jan 2009 01:55:04 +0000 (UTC), don@xxxxxxxxxxxxxx (Don
Klipstein) wrote:

In <1ngbm4heqee20btebrkidribmsqdh1up7j@xxxxxxx>, Raveninghorde wrote:
<SNIP to this point>
So how many years does it take to know the trend in global temperature?

Possibly a cycle of the Multidecadal Oscillation, though I don't know if
that is a nice periodic oscillation or more closely resembles random noise
filtered by a resonant bandpass filter. But I suspect it has an effect on
global surface temperature and has a period of 60-65 years.

If that oscillation is for real and fairly periodic, then it might be
useful to look at a stretch as short as 15-20 years and compare to a 15-20
year stretch from one cycle ago of that oscillation to see any change in
longer term trend over the past 65 years. That may still be suspect - the
1910 dip was more consolidated and deeper than the corresponding cool
times centered one cycle later.

It does appear to me that a 10 or 11 year stretch can give a poor view
of a trend if it begins with a spike going one way and ends with a spike
going the other.

- Don Klipstein (don@xxxxxxxxx)

It aslo looks like we are hitting a solar grand minima which is about
a 210 year cycle. And there are other longer cycles as well. I'm
seeing some articles saying we'll have a cooling phase to about 2030
before temperatures rise again.

For me the short term trend is important. Have we entered a cooling
phase? If so it debunks the more extreme claims that AGW has
overridden the solar cycle.

To look for a global warming that overrides solar cycles and the
multidecadal oscillation, maybe a stretch of 5-6 years with El Ninos and
La Ninas and any major volcanic eruptions filtered/accounted somehow.

The most recent stretch maybe good enough to look at is the one from the
2000 La Nina to the 2007-2008 one which was a little stronger.
Late 2006 had a weak El Nino helping it become the warmest year since
the record 1998 El Nino according to HadCRUT and both UAH and RSS
determinations of lower troposphere temperature from MSU satellite data,
and the warmest on record according to NASA's GISS and NCDC (which show a
lesser spike from the 1998 El Nino).

However, we could have the Sun and the Multidecadal Oscillation's effect
on global temperature more downhill now or soon than in the 2001-2005
stretch. I think it would be useful to compare the next stretch of years
with "no babies" (neither El Nino or La Nina) to 2002-2005.

To get 2 decent stretches with "no babies" sounds to me like something
that can usually be done over 10-16 years or so.

If AGW fails to maintain a warming trend through times when the
Multidecadal Oscillation and solar output would normally make global
temperature go downhill, then that failure may show up as early as
2011-2012 or as late as sometime around 2020 or in the 2020's.

So far, I am merely expecting warming to slow after 2005 from the maybe
..13-.14 degree C per decade from 1979 to 2011 that I expect the lower
troposphere determinations from MSU satellite data to show once 2011's
data is in and considered, probably to slower than the .11 degree/decade
that I like to find in the 1979-2008 stretch in Dr. Roy Spencer's
website's graph of UAH determination of lower troposphere temperature
anomaly from MSU satellite data.

If the 2005-2024 stretch (2 decades ending about 15.97 years from today)
shows warming at all according to all of HadCRUT-3 and -3v and NCDC and
NASA's GISS and both UAH and RSS determinations of lower troposphere
temperature anomaly from MSU satellite data, I think we're in some
doo-doo. If none of those report less than warming of .025 degree C per
decade and average of those is warming of at least .05 degree C per
decade, then the 3-4 decades after 2030 may well have warming
significantly more than that from early 1970's to 2005 (that stretch
looks to me like from smoothed HadCRUT-3 like .17 degree C per decade,
..165 degree C per decade even with the 1998 El Nino spike excluded).

- Don Klipstein (don@xxxxxxxxx)
.

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