I’m not aware of any convincing assessment of the quantitative difference between fluctuation around the increase in temperature observed (until recently) and the increase itself.

Over time, fluctuations up or down combine to become any underlying trend whether it be warming or cooling.

It is the scale of the contributing factors that is important and I take the view that human CO2 is an insignificant player for reasons set out extensively in my articles at CO2sceptics.com

In comparison ocean and sun are hugely powerful with all other variables being minor though numerous and having the overall effect of approximately cancelling each other out.

stephen: there have been numerous studies about the effect of the sun. Thay all conclude that solar activity can explain fluctuation around the increase of temps observed today, but not the increase itself!

There is no implication for public policy or the teaching of children as far as I am concerned since I am neither a politician or a teacher.

There is no implication for public policy or the teaching of children as far as I am concerned since I am neither a politician or a teacher.

See the discussion about solar influence on this thread:
http://wattsupwiththat.wordpress.com/2008/09/08/an-inconvenient-youth/

There is no implication for public policy or the teaching of children as far as I am concerned since I am neither a politician or a teacher.

If your mind is closed then indeed we must part ways.

The reason I insist on including the sun as well as the oceans is that the sun is the initial source of the energy so solar variations over time should have a significant role in dictating the power or weakness of the oceanic component.

I think it may turn out that solar variations alone are of greater influence than you currently believe but that is only intuition on my part and we will have to wait and see.

You ignore my point about the amplifying/suppressing role of the oceans over nearly six solar cycles. Even longer time scales could be involved due to the time it takes for an initial change in trend to work through all the oceans.

If climate sensitivity is high as a result of oceanic amplification or suppression then a small solar variation is not a problem.

There is no other source of energy other than the sun unless one includes geothermal flux or undersea volcanic activity (which I don’t).

I have mentioned elsewhere that going back to 1960 all the changes in global temperature change correlate with a combination of long or short solar cycles as modulated by the prevailing positive or negative oceanic oscillations at the time. I have seen data that takes the correlation back to 1900 but cannot recall where.

I do not seek to try and persuade at this point. I am content to wait for more changes in trend to see whether the correlation continues to hold.

The only difference is in the amount of variation.
but isn’t that the all-important difference? Does it not matter if the amount is 0.0000000000000000001% versus 10%?

Who is to say that the current estimates are any more accurate than those of 20 years ago? All are based on a collection of assumptions.

The people making the estimates say so. They [we] carefully update the ‘assumptions’ all the time in view of what we learn. The recent ones are really better than the old ones. This is not just assumptions.

Turning this around, if all are based on a collection of assumptions, then they cannot be taken as strong evidence that the sun has changed its output, so your observational support falls away.

Multiply it up to planet size and there’s a sizeable amount of heat energy involved however much one tries to minimise any solar signal.
One is not trying to ‘minimise any solar signal’. One is trying to assess how big it is, without the built-in bias that lies in the phrase ‘trying to minimise’. Trust me, solar physicists would be motivated to maximise [if anything] the solar signal, as it will make their field all that more important, with funding, prestige, etc.
And, multiplying up does not change the relative proportions of the change wrt the total, it is still only 0.1%

there is enough correlation between solar cycle behaviour and changes in global temperatures
this is precisely the point. What correlation? and with what significance? Oh, I’m well aware of the hundreds of correlations that are claimed, but select from all those, the ONE that you think is compelling enough for you to make the above statement. and we can discuss that one in detail.

Who is to say that the current estimates are any more accurate than those of 20 years ago? All are based on a collection of assumptions.

It’s simply a matter of climate sensitivity not a complete absence of a solar signal.

As I’ve already said the oceans could achieve the necessary amplification or suppression of even a small solar signal over periods of 60 years covering a full positive and negative PDO cycle spread across nearly six solar cycles.

Additionally there are also a lot of square metres on the planet surface let alone around the outside of the atmosphere. An apparently small solar signal can be partly a result of choosing such a small area subdivision. Multiply it up to planet size and there’s a sizeable amount of heat energy involved however much one tries to minimise any solar signal.

I think one has to start from observations and subject to lags due to say oceanic reactions to solar changes there is enough correlation between solar cycle behaviour and changes in global temperatures to persuade me that the issue must be recognised and given due weight.

Of course others may disagree.

I do agree with Leif to the extent that TSI may well not be an adequate explanation on it’s own but it looks pretty suspicious even if the historical variance has been overstated.

This is indeed ‘junk science’. Keep showing old, outdated plots. Not even Judith Lean believes that old plot anymore. She even agrees that no long-term variation has been detected. See her slide on page of her presentation at SORCE in 2008:
http://lasp.colorado.edu/sorce/news/2008ScienceMeeting/doc/Session1/S1_02_Lean.pdf

Her conclusion about the contributions of the different sources of TSI:
5-min oscillation ~ 0.003%
27-day solar rotation ~ 0.2%
11-year solar cycle ~ 0.1%
longer-term variations not yet detectable – ……do they occur?

Thus, bottom line: The variations that we thought [10-20 years ago] were present are no longer thought to be so. Lean [with Wang] updated the old useless 2000 reconstruction in 2005, and now she even acknowledges that THAT one is not correct. You can see the evolution of the thinking about TSI over the last 20 years here: http://www.leif.org/research/TSI-LEIF.pdf and here: http://www.leif.org/research/Seminar-LMSAL.pdf [page 20].

It might have been something to do with this but Leif disagrees:

http://www.junkscience.com/Greenhouse/irradiance.gif

I do agree with Leif to the extent that TSI may well not be an adequate explanation on it’s own but it looks pretty suspicious even if the historical variance has been overstated.