Friday, September 20, 2013

There's a new UN IPCC climate report coming out Real Soon Now. Here's what you need to know.

The report is going to say - wait for it; wait for it - that ZOMGTHERMAGEDDON!!!1!!!eleventy!!!

Oooooh kaaaaaaaay.  Here's what you need to know.

The report  (IPCC AR5, or IPCC 2013) is based a "consensus" that is based on Model predictions.  So the first question is how have previous IPCC reports' predictions fared against the actual, you know, observed data?  Long time readers already know the answer:

This is the fifth Assessment Report (AR5).  AR1 (from 1990) said that temperatures would have risen by 0.75° by now - they've actually risen by 0.25° - assuming that you trust the surface temperature record, which I don't.*  But even with this, you're looking at ~ an 80% miss in projections.

Later Assessment Reports haven't missed as badly, partly because they were adjusted down from AR1, and partly because they haven't had as long to run.  A shorter time interval gives you a lower percentage deviation from predicted.  Still, the 2007 AR4 predicted that we'd have seen almost twice as much warming as even the unreliable surface temperature record shows.

So what gives?  This isn't just a miss, this is a massive miss.  Especially for something where the "Science is settled".  Georgia Tech's Judy Curry brings the second piece of the puzzle which gives you a remarkably complete view of the problem:
My blog post on the Fyfe et al. paper triggered an email from Pat Michaels, who sent me a paper that he submitted in 2010 to Geophysical Research Letters, that did essentially the same analysis as Fyfe et al., albeit with the CMIP3 models.


Drum roll . . .  the paper was rejected.   I read the paper (read it yourself), and I couldn’t see why it was rejected, particularly  since it seems to be a pretty straightforward analysis that has been corroborated in subsequent published papers.


My own personal reaction to the rather lengthy [peer] reviews (12 pages worth) is that all of the reviewers rejected the idea that IPCC model projections could be compared in such a way that led to the conclusion that indicate cause for concern regarding the consistency between climate model projections and observed climate behavior under conditions of increasing anthropogenic greenhouse-gas emissions.
I'm shocked, shocked that the peer reviewers rejected an actual, you know - scientific - comparison of the model predictions to the actual, you know - observed - temperatures.  If that were to be discussed in public, well, that might be wholly unfortunate:

And so the twitter (pithy) reply to people who sneer at you that the "science is settled" is "That's what Major Strasse said."  And everyone knows how that came out:

Soo we will hear that the IPCC AR5 Report has been shot.  No doubt this will be an excuse to try to round up the Usual Suspects.  You know, I get the feeling that this is the beginning of a beautiful scientific friendship.


rinfanti said...

OK: So I finally have to comment that the linking of Casablanca with climate change (NOT) was brilliant and it made my day.

drjim said...

You had an asterisk after you said you didn't trust the surface temperature measurements, but no further explanation.

Who's surface temp measurements don't you trust (probably .GOV's) and why?

JD(not the one with the picture) said...

It should be obvious that when they release the evil, killer AR15 we will all die.