Comments Dan Halen has made

It's an explanation, not an admission

What he's probably getting at is this:  I make a computer model, I have various measurements I take or assumptions I make that lead to uncertainty, some of the uncertainties are small, others large.  I carefully propagate my error mathematically through the calculation at the end and publish my results.  Let's say they boil down to, oh say something like, I dunno, a temperature.  The number is published as 5C +/- 2C.  Of the 2C worth of uncertainty about 80% is due to a single rather uncertain measurement or factor.  Thus I say "factor A accounts for the majority of uncertainty in this value".  This does NOT mean that my whole experiment or model in useless or invalid.

Of course the best test of a computer model is to match it against the real world.  This has been done through hindcasting.  You take known historical data on CO2, pollutants, etc... and run the GCM.  You then see how well the temperatures it produces matches what happened in the real world.  It turns out that the current GCMs are quite good at matching with known historical data in fact.  If the model clouds were behaving much differently than real ones this would not have been possible.

You also seemed to have missed the bit at the end where he told you that nothing in the past indicates that clouds will save us.  We've seen massive warming lately along with massive output of GHGs.  The clouds haven't saved us yet, why would anyone think they will suddenly start doing so?  And where were the clouds during the paleoclimactic periods that were very warm?  Napping on the job again.On 'Models don't account for clouds'--Clouds are complex and uncertain, but unlikely to stop warming posted 1 year, 5 months ago 6 Responses