Hi Bigmal,

I had a look at SPM fig 2, as you suggest. I really don't see what your problem with the figure, or the IPCC in general is (for those who are interested, the report can be downloaded here:
http://www.ipcc.ch/).

Now, look at the bottom of the figure, marked "Total Net Anthropogenic". This gives a net radiative forcing of +1.6W/m2, with a confidence interval of +0.6W/m2 (min) to + 2.4W/m2 (max). Please note that you can't just add up, the individual components because the error is distributed. The further away from the “middle” value, the less likely it is, so the confidence intervals do not add up linearly. (see: http://mathworld.wolfram.com/ConfidenceInterval.html for an explanation).

Now, it's true that there are uncertainties, particularly with aerosols. A good discussion of this is:

http://www.realclimate.org/index.php/archives/2007/02/aerosols-the-last-frontier/ )

Aerosols don’t change the fact that increasing CO2 concentration in the atmosphere results in increased radiative forcing. The uncertainties are reported as the errors in the model predictions (eg SPM 4 and SPM 5).

Uncertainty does not imply that the results are useless.
For example, figure SPM 5 tells me that, for the B1 senario, there is a 68.2% probability that the average surface temperature will be 1.4 and 2.2C warmer than the 1980 – 1990 average.

However, the dominant uncertainty is the emissions (see fig SPM 5). They also don’t include carbon-cycle feedbacks or advanced ice-sheet dynamics (page 14). This is likely to underestimate warming.

Also, models are not “tweaked” to conform to observations. This is not true. Models are tested and validated rigorously, by attempting to reproduce phenomena, such as the 1991 eruption of Pinatubo, as well as reproducing the ENSO cycle, and other natural variations.

http://www.physicstoday.org/vol-60/iss-1/72_1.html

Parameterisation of certain variables (ie cloud formation) is done both statistically and using physics.

http://www.climateprediction.net/science/model-intro.php#par_ame

However, for the most part, climate models are driven by physics of the climate system

See also
http://www.realclimate.org/index.php/archives/2005/10/modeller-vs-modeller/

I don’t mean to imply that models are perfect. But they give our best guess, and they’ve been pretty spot on up until now. We ignore the climate scientists at our peril.

ChrisC

Thank you for your thoughtful response and the references.I am aware and have read most of these, and dont derive the same confidence that you do.

For example the feed back effect of clouds has a huge impact and is clearly highly uncertain, but still the modellers say they are good enough for us to invest the farm in a prediction that goes out 100 years. That is just not credible.

Further there may be X100 scientists involved in producing these reports but when some of the authors and reviewers, have the same view that Aynlsey Kellow makes, and he is not alone, then it casts doubt on the integrity of whole IPCC exercise.ie The IPCC is so hide bound, and single minded in one direction against anything not in accord with the group think view is automatically sifted out, so that only the extreme and dire is presented. The CSIRO here does the same thing. That makes me and many others very suspicious.

When someone presents a Business Plan or prospectus like this any investor would just walk away.

Also the evidence presented by the IPCC documents still does not, establish unambiguous cause and effect to the same degree one would expect in medicine. There is some warming occuring, which is having some effect in some areas, but is it unambigously the consequence of more C02?. Not on your nelly.

Fianlly I am still left with the condundrum ( one of many). Why is it that the Modtran3 model of radiative transfer shows that the flux at the top of the atmosphere flat lines, with increases in C02.ie the more we add the less the warming effect and this is suported by satellite measurements.

One last condundrum, have a google of the River Tornio in Finland and explain to me why the date for when the river becomes free of ice in Spring, shows a consistent trend SINCE 1690.ie long before coal fired power stations and 4wd's

BTW I think the authors points in the article herein are on the mark.

Spot on, Big Mal, thanks Pegasus.

Of equal impact on climate change is variations in the rate of absorption and reflection (albedo) in the landscape. The clearing of a forest will release large volumes of CO2 in the atmosphere which, in theory, will tend to warm things up.

But that clearing will also reduce the absorption and increase the albedo of the modified landscape and this will cool things down.

The problem is that the IPCC muddlers are only measuring the carbon released. And in most cases long before the carbon actually gets into the atmosphere. So the, limited, warming part of the equation is factored in immediately while the long term, cumulative, cooling part is left out altogether.

And surprise, surprise, their climate muddles predict runaway warming.

But if a farmer is to be penalised for releasing carbon when he clears (mostly regrowth) forest, then why is there no equivalent system of "cooling credits" that he will earn and accumulate for as long as his paddock remains as a paddock?

And why can't I get "cooling credits" for converting my heat absorbing roof tiles to heat reflecting silver roof iron?