On 19/10/2012 16:09, Tudor Hughes wrote:
On Friday, 19 October 2012 10:10:54 UTC+1, Martin Brown wrote:
On 19/10/2012 09:37, Graham Easterling wrote: On Thursday, October 18, 2012 10:39:34 PM UTC+1, Stephen Davenport wrote: On Thursday, October 18, 2012 8:32:16 PM UTC+1, Steve Jackson wrote: Stephen, I hope my A level students will rationalise that warming in Scandinavia might just be more than a localised event, mirrored perhaps in the UK, so certainly of continental proportions, long before fossil fuel burning became an issue. =========== Well, I hope they're smart enough to notice a faulty syllogism that concludes the *certainty* of a continent-wide phenomenon based on flimsy premises of "might just be" and "mirrored perhaps". And "continental proportions" still ain't global. Stephen. I am bemused by people (not just Steve) using past variations in the climate to justify sceticism over global warming. I would hope everyone on USW would accept:- 1. The earth has warmed over the last 100 years 2. CO2 is a greenhouse gas and mankin
d has been pumping it into the atmosphere. The only real arguments should be over the relative importance of other factors influencing the Earths climate and positive/negative feedback mechanisms. As these are poorly understood then it seems commonsense that attempts should be made to minimise mankinds affect on the atmosphere. Saying the Earth's been warmer/colder in the past is irrelevant, of course it has! They are using a common fallacy that sets up the strawman that everything is due to CO2, then show that some changes are natural and then deny that any of it is due to CO2. Works for Daily Wail readers. If you look back over the past 150 years where we have pretty good records (even sceptics sponsored research like BEST which goes back further) shows additional warming from GHG forcing after 1970's. Roughly speaking the natural rise in global temperature due to solar flux over 150 years and the rise in the 3 decades from 1970 to 2000 due to GHG forcing appear to be about
equal in magnitude. Although I happen to thing that some of that latter rise was the upside of a periodic luni-solar term of 58y (2x Inex) also seen to peak in 1940, 1880(weak) and 1824. We should be on the downside of a periodic term at the moment but global temperature rise has merely slowed. If my hunch is right it will pick up again with a vengeance about 2018. It is known that the sun is a weak variable star with 0.1% TSI variability over the solar cycle (more at some wavelengths) and from astrophysics that on geological timescales it will get brighter. From an experimentalists point of view it would be handy if the sun would give us one solar cycle with 1% TSI variation so that we could more accurately characterise the Earth's actual impulse response. As it is we are stuck with the deniers chanting "it is only a theory" as they do about evolution, big bang cosmology and relativity. -- Regards, Martin Brown

Most of what you say is true but you reduce your credibility by mentioning "luni-solar" terms, which influence the frequency and periodicity of eclipses and can have no effect whatever on the earth's climate with or without AGW. In any case you do not say what these luni-solar terms represent or why they are supposed the affect the earth's climate.

Tudor Hughes, Warlingham, Surrey.

Actually I think they do and I may yet be able to prove it. The Keeling
and Whorf analysis in the PNAS Keeling Tides papers (available online)
also agree with me although their analysis is itself flawed. There is a
58y peak in their power spectrum despite the way they did the analysis.

http://www.pnas.org/content/94/16/8321.abstract
http://www.pnas.org/content/97/8/3814.abstract

Full text is available from these links.

I am having some difficultly getting my paper published because I am not
a bone fide climate researcher so what I have may yet end up being first
published on WhatsUpWithThat (wouldn't that be ironic).

You are correct that the "Luni-solar" terms, influence the timing,
location and periodicity of eclipses - but they also influence and
fairly strongly at that the extent of maximum tidal range in spring
tides as the moon-sun-earth configuration drifts around. In particular
annular eclipses represent the strongest possible tidal action and there
is a complex relationship between the sun, moon and position over the
continents that affects how much net churn the oceans experience.

Thrashing the oceans about more bring cold water up and shifts heat out
of the atmosphere and conversely when the tides are slightly weaker
there is additional atmospheric warming. It doesn't take much as the
heat capacity of water is huge compared to air.

Present theories favour the nonlinear thermal modes as explanations of
the various multidecadal oscillations. I think these modes are being
excited by the tides. So did Keeling & Whorf.

--
Regards,
Martin Brown