So, Bazz, are you saying that knucklehead humans are likely to experience "collapse" due to financial limits - because of unfettered industrialisation before they experience "collapse" due to climate change - because of unfettered industrialisation?

That's sounds much more reassuring.......

Poirot,
What I am saying is that co2 might not be our biggest problem.
That collapse is a real risk, but not because of co2 emissions.

The US has met the co2 reduction targets, not because of taxes etc but
because they are burning less oil. They are burning less oil, down from
21 Mbpd to 18 Mbpd by lower economic activity and buying smaller cars.
They are also using less coal (I think, not sure) because significant
number of power stations are changing to natural gas.

Costs have risen about four times since early 2000s and that must have
some effect and it can no longer fall.

You sound skeptical, or are you a denier ?

Bazz,

Don't forget Keystone.....

They're burning less oil - buying smaller cars?

Good!

They are also exporting more coal because they are using more shale gas instead.

http://en.wikipedia.org/wiki/Shale_gas_in_the_United_States

http://www.eia.gov/todayinenergy/detail.cfm?id=8490

warmair, I'm not questioning how the error bars were arrived at. For any given set of data that's trivial, but it doesn't mean the data has any validity as a predictive model. As I discussed earlier, a projection of human population from around 4000BCE to now would have had a high degree of confidence of an upper bound of well less than 1 billion and a lower bound of perhaps a few tens of millions or even less. Yet here we are, about an order of magnitude more of us than could have been predicted back then with the best data.

It is because human population has experienced that sudden rapid increase in growth that we are discussing the issue of AGW. There are many factors emerging that may cause a sudden collapse of the human population by negating the effect of some of the most obvious technologies that have allowed it to expand so rapidly. They include the imminent failure of antibiotics, depletion of cheaply and simply accessible sources of phosphates, inadequate fresh water resources and more. If the current population is a spike, not an approach to a new pseudo-equilibrium, the issue of AGW becomes moot.

I was in Brisbane during the 2011 floods. They occurred on a fine day with no rainfall to speak of and high tide happened not to coincide with the peak river flow. If it had kept raining locally or the peak flow had been a couple of hours different the flood might have been a meter or so higher (5.5m instead of 4.5m, nearly 25%), which was the prediction just a day earlier.

Just 3 variables in a pretty simple system which is highly constrained and very well understood yet such a large error.

It seems to me that there is a real failure on the part of the populace, including politicians and especially journalists, to grasp just how complex the problem of climate is and how little we genuinely understand about it. Because of that much of what is written is more akin to theology than science.

I disagree with the proposition that metastability and pseudo-equilibria are not a feature of global climate. The semi-periodic glaciations are an excellent example of just that on a fairly short time scale, while long-term shifts from one type of climatic regime to another are also readily inferred from geological evidence.

In fact, it's such a feature of climate that it occurs at every time and geographical scale you can think of, which is a feature of chaotic systems with fractal geometry.

It seems to me that we are living on borrowed time with respect to the global climate remaining within the current short-period pseudo-equilibrium, whatever we do and whether we make it happen or not. We're really only even around as a global species because the global climate has been so consistently suitable for us and our ancestral species for an unusually long time, although it has varied considerably around a mean and was starting to head down slightly.

http://upload.wikimedia.org/wikipedia/commons/b/b8/Vostok_Petit_data.svg

An interesting discussion of the way climate may have stimulated human technological advance is at

http://www.scientificamerican.com/article.cfm?id=prehistoric-climate-change-may-have-encouraged-human-innovation

It also points out that there are still large semi-periodic changes in global behaviour that we don't understand.