On Fri, 14 Feb 2014 07:25:32 -0000
"Ian Bingham" wrote:

The HadCRUT series of world temperatures show that average world
temperature stopped rising around 2000, and if anything has been
slowly falling since. The question is not so much where the heat
energy has gone (it has evidently gone into beefing up the
atmospheric circulation, both horizontal and vertical) as why
temperatures stopped rising when they did. What happened around 2000
to cause that change?

The global temperature has continued to rise since 2000, albeit more
slowly than before. I take 11-yr means in order to rule out any
possible problems through the solar cycle - even though that actually
seems to make little if no difference - and that shows a 0.08C rise
from 2000 to the last available year, 2008. If I was to pick a year
since when global temperatures have flatlined, I'd go for 2005.

I've pointed out before that the slowdown coincides with a negative
period in the Pacific Decadal Oscillation (PDO) Index. Again using 11-yr
rolling means, the PDO index peaked in 1983 and has been negative since
2003. However, as we shall see, this negative period isn't all it's
cracked up to be.

One should be aware of the fact that the calculation of the index takes
into account rising global sea temperatures in order to make the PDO
more easily identifiable. Because of this, the negative period early in
C20 is 8 years in length but when the corrections are removed it
becomes more than 21 years long. The current negative period in the
index looks to be of similar length and almost 0.2C lower but the
recalculation shows no negativity at all and the value is more than
0.5C higher than the earlier period.

This probably explains why the people who predicted a negative PDO
would drag global air temperatures back to normal got it wrong.
However, to be fair, they did predict it would have an effect on
temperatures which is more than most climate scientists seem to have
managed.


--
Graham P Davis, Bracknell, Berks. Mail: 'newsman' not 'newsboy'.
"Welcome to the year of the whores. People around the globe celebrate."
- BBC News subtitle