John - I'm not aware of any climate scientists who've ruled out...

John - I'm not aware of any climate scientists who've ruled out pauses between 1990 and 2100.

But here's the problem: To get a 4 degree warming, or even a 3 degree (the model average) warming, let alone a 2 degree warming, we need to experience a combination of the following factors over the next 85 years:

(i) Either no more pauses, or pauses of far shorter duration than those two multi-decadal pauses experienced in the 20th century, over which time we experienced an overall warming of around 1 degree; and

(ii) During the multi-decadal "warming" phases following any pause, the rate of warming has to be way in excess of the highest rate of warming yet experienced (i.e. the period between the late 70s and the late 90s).

If the duration of the current (and any future) pause were to be similar to those experienced last century, then we'd have to be looking at rather nasty "Jack-In-The-Box" warming phases for these 2, 3 or 4 degree projections to eventuate.

That is fabulous. There's simply no precedent for this. If we assume for the 21st C a repeat of the 20th C duration of pausing and warming cycles (during which there was a monotonic increase in atmospheric CO2 concentrations) and a higher rate of warming than the 70s to 90s period, followed by an even higher rate of warming to the end of the century, we will still end up short of a 1.5 degrees increase.

Both (i) and (ii) are "articles of faith", because whilst they may occur, the probability of both occurring is so low that one could hardly call such faith "science".

I've come up with 1.3 degrees using this common sense derivation. Judith Curry, using every available climate science tool at her disposal, has come up with - coincidentally - a best estimate 1.33 degrees.

Makes one wonder if "pauses" - even if acknowledged - were properly taken into account by the climate scientists when constructing and adhering to their models.