Or, “leaky buckets”, as I believe we share at least some reluctant mutual willingness to think of them as.
Actually, there’s a rather large difference between analyzing demographical information and building models.
In the case of climatology, climate is dependent on a vast number of factors (variables in the model) many of which are poorly understood.
Which is one of the two main reasons why you have warming estimates which range from .2 degrees per decade to 1.2 degrees per decade. How your model comes out is entirely dependent on what assumptions you make regarding these variables and their growth rates. Depending on your assumptions, the warming of the earth can range from the aformentioned 1.2 per decade to….well…cooling slightly, actually.
There are jokes about nonstatisticians who try to do statistics. :-)
The second reason is that data quality is extremely difficult.
So, although I quite agree that we are in a secular warming cycle, and that AGW is a component of that cycle…..after that, more detailed predictions become more problematic.