[Arragonis]

Originally Posted by jamesqf

...(Personally, I've always found bending over to stick my head in the sand quite uncomfortable.)

You have decided to go off on the "I know best route" - please note I'm not responding in kind

Originally Posted by jamesqf

Why not actually read up on some of the science yourself?

I have, quite a bit, so

Originally Posted by jamesqf

Simple answer: it hasn't.

Simple reply - Yes it has.

Pantomime reply - Oh yes it has...

More complex answer - any warming, cooling or steady state depends on the start and end points selected, as the UK Met office recently pointed out. Both sides choose start and end points to try and support their arguments, or even try and suggest an "escalator" which kind of works - for the small period we have temps for, maybe.

Simple bottom line - we still don't know any measured temperatures are outside what has been experienced on the earth before.

Originally Posted by jamesqf

When you put a pot of water on the stove for your tea, does it come to a boil the instant you turn on the flame? The Earth is a big place with a good deal of thermal mass. It will take quite a time - over a thousand years, considering deep ocean circulation - to reach an equilibrium.

Agreed, the Earth is a very big and complex place where a huge number of interractions between different factors take place - CO2 and other greenhouse gases, the oceans ability to hold cold and warmth, clouds, the sun etc. Even with £bn spent on modelling it we still don't understand all of it and we don't have models which fit with what is happening all the time.

The Met office I mentioned above happily claims it uses the same models for weather prediction as for climate modelling - well it has had 2-3 years of major cock-ups in forecasting in the UK and has now decided not to bother. One amusing incident involved the chief scientist being snowed in at Heathrow on her way to the Rio conference to deliver a report on how warm the UK was getting - my how we all laughed.

This also makes a basic experiment - say a glass sphere filled with CO2 warmed by a light bulb Arragonis Junior was asked to perform at school recently - valid from a "basic physics" point of view but invalid when it comes to predicting what is or may be happening to the planet.

I would support more research into this, not a head in the sand stance is it ?

Originally Posted by jamesqf

Just off the top of my head, a few ways to deduce past temperatures.

Yep they are reconstructions. You take two periods of known temps and "thing you observe" (TYO). Using one period you create a mathematical model of one to the other - so you can determine temp from TYO. Once you have a model which passes a statistical confidence test you then take the second period and check TYO still predicts temp vs reality. Once this second relationship also passes a confidence test you can then apply it to TYOs from periods prior to known temps to try and calculate what they are.

The real problem lies with the maths. A recent paper on Australian temps fell foul of this - not on the measurement but the maths. The fault was found by a non-scientist after it had passed peer review, the paper is now withdrawn and dead - but will appear in the next IPCC report via another route. Go figure.

But the bottom line is that reconstructed temps are still a (well) educated guess.

Some are more accurate than others, some are more contraversial than others. The Hockey Stick, which seems to have disappeared recently, was one very complex reconstruction using all sorts of data - tree rings, sediments, ice cores. However some evidence seems to suggest it can't be reconstructed due to dodgy maths and some rather strange data handling - such as using one data set upside down. A lot of these questions remain unanswered. I've read both sides, ClimateAudit and RealClimate. I would love to see this resolved with a debate from both sides, but I suspect its not going to happen.

So yep - I've read the science, on both sides. This method

Originally Posted by jamesqf

... 3) Dendrochronology - studying tree rings gives clues as to temperature & rainfall when each ring was formed. Similar methods can be applied to fossil shells, corals, &c.

is especially questionable as the influence of rainfall, sunlight or the action of other animals or plants over time can skew the growth rings but leave no visible record. One tree was found to have a completely different pattern on one side to the other. It is also difficult to establish where the tree line is at any time in the past - there are remains of trees above the current tree line in the USA - it must have been warmer for them to be there ?

There is also not a huge amount of dendochronology going on - or at least not enough to get an accurate world wide record - both sides acknowledge that and both sides suggest more research, which I would agree with. Again head out of sand.

Originally Posted by jamesqf

Or do you deliberately maintain ignorance because it's more comfortable?

No, I just like to read both sides of the debate - I have books from both sides on my shelf. I find not having a fixed view seems to less shall we say "head in the sand limiting". I used to be a (and I don't intend to use this word in an insulting manner) believer in CAGW too - honest. Was nearly a member of WWF, Greenpeace, campaigned for Kyoto, voted Green, even thought peak oil was a real threat now - everything in the past.

But as an economist changing his mind once said

Originally Posted by John Maynard Keynes

When the facts change, I change my mind. What do you do, sir?

There is another level to the debate relating to the original posting. If we have passed another tipping point (there seem to have been quite a few over the last 20 years) then maybe we would get more return from a focus on mitigation instead of prevention ?