Roger Pielke, 30 April:
there is in fact nothing that can be observed in the climate system that would be inconsistent with climate model predictions. If global cooling over the next few decades is consistent with model predictions, then so too is pretty much anything and everything under the sun.
over the 30 year time frame there will be strong warmingRoger:
I see that you neglected to address my central question
I explicitly wrote "over the 30 year time frame there will be strong warming" - and actually 20y would be a safe bet too.
I see that you have once again avoided addressing this question.
Me here in more detail:
Warming over 30 years is assured, 20 years must be "very likely", 10 years I would certainly say "likely" but that is a bit of a rough estimate.
I could do a detailed calculation about the probability of different trends over the next 30 years, but that's already been done.
James, when you write, "Warming over 30 years is assured, 20 years must be "very likely", 10 years I would certainly say "likely" but that is a bit of a rough estimate" you are much closer to what I am looking for. I am asking for somewhat less "roughness" in these estimates, and grounding them more quantitatively than this sort of hand-waving which is a common response.
you asked for more quantitative estimates, but did you read the link I provided, where such quantitative estimates were explicitly presented 6 years ago?
If, after reading that (and the two papers it refers to) you still have a question then feel free to follow up.
If you think that I'm focused on 2020-2030 (the subject of the essay in Nature that you linked to) then you are not really paying attention.
Roger, you started off with "if global cooling over the next few decades..." (my emphasis) which remains on your blog even after several people have pointed out that it is a gross mischaracterisation of the Keenlyside paper. So I pointed you to explicit probabilistic predictions about the next few decades which are as clear as day about the probability of cooling over that time frame.
Now you say you are not focussed on the next few decades...
If you want shorter term, I'm sure you have already seen the Smith et al Science paper, within which 50% of years post 2009 are predicted to beat the 1998 record. But as you can see, this is still a rather young area of science, and Keenlyside disagree to some extent (although not as strongly as some have portrayed it - I think their 10y mean forecast could still validate even if we see some new records).
Roger again (not in response to me, but bringing up the topic again on his blog):
You can just clear all of this up by answering my original question:
What observations of the climate system to 2020 would be inconsistent (lets say at the 95% level of certainty) with the climate model projections of the IPCC AR4? It is a simple question. use global average surface temps from UKMET as the variable of interest if you'd like, since that is what we've been discussing, or use a different one.
Stott and Kettleborough estimate that the global mean temperature in the decade 2020–30 will be 0.3–1.3 K greater than in 1990–2000 (5–95% likelihood range)and
Knutti et al. find that the projected distribution of likely surface warming is independent of the choice of emission scenario for the next several decades; that the probable warming for 2020–30 relative to 1990–2000 is about 0.5–1.1 K (5–95% likelihood range)
Also relevant: Eli Rabett and RC.