[renormalised (Carl)]

1) By stable, I mean that for the last 600,000+ years or so we have seen cycles, where the max and min temperatures are similar (compared with the range over the 2.5 billion years before that). All the evidence I have seen points to us now tracking out of those cycles, thus we have the problem.

It hasn't been stable, in any terms. Actually, the global average temperautures for most of the last 550ma have been far more stable, for vastly longer periods of time than now. During the Cretaceous, the global average temperature remained at around 18 degrees (6 above now) for almost 100 million years!!!. 6-10 degree up and down fluctuations over a 600Ka period don't even count.

2) The ecosystem arable stuff is quite a bit more complex than you point out and those same changes occurred when the world went from being primarily covered in forest to having large areas of grassland (also the grassland can't hold as much C, so if it had always been there we wouldn't have all the coal we are burning), changing agriculture techniques (no till etc.) means that bare soil is increasingly less common. But I don't disagree with your point.

Yes it is far more complex than what I wrote about there, I'd have had a much larger post if I went into the nitty gritty about it!!!!

3) Temperature measurements are made at various levels in the atmosphere (and with various results), plus urban heat islands etc. are adjusted for in the models and the data interpretation, so I don't think that those factors negate the predictions for future climate.

They are now, and in the last 50 or so years, but what about the preceding 100 or so years...and they've only had the use of radiosondes for atmospheric measurements since the mid to late 40's. Satellites for even less time. The data isn't as good or as complete as it should be.

4) I'll freely admit I know little if anything about the major controls on global temperature over the billion year timescales you are talking about (though I am fascinated). You appear to be suggesting that those controls are not well understood? Considering the differences that you have pointed out between then and now, and the relative recent stability (see my definition above!!!!), I would still say that making comparisons with the last million years or so was a much better option than looking at pre-cambrian times....

I'm not looking at the Pre-Cambrian for the most part. Only that geological processes have been relatively similar to now for the past 2500Ma. The climate has certainly changed, as has the atmosphere. Go far enough back and you've got an atmosphere that's mainly nitrogen, water vapour, some methane and ammonia, and over 100 atmospheres of CO2 content. Not my idea of a happy atmospheric mix!!!. What's more, it's a secondary atmosphere and not the one the planet originally outgassed.

5) I agree totally with your paragraph on deforestation, I also agree absolutely that CO2 is not the only player in climate change. I don't think anyone would disagree, certainly not the modellers, who do include a whole raft of things.

The only way to know what the modellers have used in their models is to look at the algorithms used and the assumptions they've used in making the models. Some may have included deforestation, others may not. What interests me is though there are other factors which are contributing to climate change in just as important ways as CO2, why is there an almost religious belief in the cause being "only" CO2 emissions. That's how it appears to being played out.

So in summary, the difference between you and me is that you consider CO2 increases to be a smaller impact than most models predict and that possibly the degree of warming is overestimated due to biased data?

My opinion is basically that all areas of biology are already seeing the effects of climate change (whatever the cause). Not being a climate scientist (but also not being totally ill informed) I have seen no convincing arguments that the basic assumptions of the "97%" http://www.iceinspace.com.au/forum/..../winking70.gif are incorrect and I don't have the background to judge whether any of the "3" have some wacked out idea that might just be correct. I'll exclude from that 3% all the jokers who are peddling disinformation for some end I don't understand.

Yes, nearly correct there...what I'm trying to get at is that the impact of the riding CO2 levels isn't the be all and end all of what's changing the climate. There are other factors just as important which are contributing but you hear very little about them. All you get is the CO2 bogey man and very little else. There's a lot more to the results being published than pure academic study and reporting and I think those leaked emails recently, have established that and don't believe for one minute it's only confined to those scientists involved. They have done the whole debate a complete disservice and science no favours either. If I was the chancellor of the university/ies they were at, I would have dragged them before an university council and made them explain themselves. If they didn't have a damn good answer to back themselves up (which they wouldn't), they'd have been charged with gross misconduct and had their tenures revoked. I'd have sacked them immediately and advised the governments not to take their studies on their word, or anyone else associated with their studies...that includes the IPCC, which they were a part of.