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Latest Blog Posts

• 23.05.2013: [jules' pics] NCAR
  

  Ben wishes to star on the blog yet again (spot him here). But first, here is NCAR, his workplace, which seems to be ageing awfully well for a 1960s concrete structure.

  Perhaps the sandy concrete is soft enough that the surface remains fairly fresh looking. Perhaps that means it is wearing away, but there looks to be plenty of concrete left.
  
  And here are Ben and friends at lunch in NCAR's famous cafeteria. There's not much James and I wont do for a free lunch, so in the afternoon we entertained the workers with seminars.
  
  --
  Posted By Blogger to jules' pics at 5/23/2013 12:16:00 PM
  Source: James' Empty Blog
  

• 22.05.2013: [jules' pics] Madness
  

  "We like driving in our bus,
  It is far too big for us"
  (sung to the obvious tune)
  

  Odd to see a car so big that makes James (6.5 feet tall) look like an ipsy wipsy imp. However, there is methodism in our madness. Next week the in laws arrive to be taken on a road trip across the Zenlands of Wyoming and Utah. In our bus we hope they will be able to swing their legs about in the back without getting DVT. It is a little alarming how well it climbs. Must have a massive engine, and is probably getting about 1 mpg. Hopefully it also has a massive tank. Oh well. At least it isn't using as much power as the NCAR climate model ensemble runs on the Yellowstone computer (also in Wyoming).
  
  --
  Posted By Blogger to jules' pics at 5/23/2013 02:20:00 AM
  Source: James' Empty Blog
  

• 21.05.2013: [jules' pics] The world from the air
  
  Been seeing far too many aeroplane views recently, but even supposedly dull countries can look quite interesting from the air.
  
  --
  Posted By Blogger to jules' pics at 5/22/2013 06:56:00 AM
  Source: James' Empty Blog
  

• 20.05.2013: More on that recent sensitivity paper
  
  Now I'm embarrassed at my naivety...it is all as clear as day. The story goes as follows:
  
  Way back in the mists of time (well, about 2011 or so) the IPCC authors agreed that the "likely" value for the equilibrium climate sensitivity was 2-4.5C. They then wrote the first draft to match, which was easy enough as they seemed to be unaware of most of the recent literature on the matter, and could easily brush off the few papers they did know about (like ours) as outliers.
  
  Inconveniently for them, the observations of the planetary energy balance are actually incompatible with their preferred choice, and as well as some reviewers telling them about the papers that had already appeared, more papers continued to be written - too many to be just ignored this time. So that left them with a bit of a credibility gap.
  
  The brilliant solution they have come up with is to write a paper on the planetary energy balance, which in numerical terms of course basically confirms what all the recent papers have said, but describe this with the phrasing that their result "is in agreement with earlier estimates, within the limits of uncertainty." (Here, "earlier" clearly refers to papers which do not use the last decade of data, ie those up to around AR4 time). Thus, this paper can be cited as support for the 2-4.5C "likely" range! They've even got one of their loudest critics, Nic Lewis, to agree with this!
  
  Whoever came up with that wording certainly deserves a Nobel prize...for chutzpah. I suspect that Nic may regret putting his name to it, although he could argue - with some justification - that the numerical results should outweigh the verbal gymnastics.
  
  Note by the way that it's not just the recent decade of data that points to a more moderate sensitivity estimate. For example, back in 2000, Forest et al generated an 90% range of 1.3-4.2C, when they used an expert prior - but at that time, the IPCC experts had all decided that a uniform prior was the correct approach.
  
  Source: James' Empty Blog
  

• 19.05.2013: A chink of light at the end of the tunnel?
  
  At last the great and the good have spoken. There's a new article in Nature Geoscience concerning the energy balance of the climate system, which basically confirms what had already been presented in the slew of recent papers pointing to a lowering of climate sensitivity estimates.
  
  The analysis itself is not particularly novel or exciting: what makes it newsworthy in my view is the list of authors, which includes some who had previously been trying to talk down these recent estimates (e.g. Knutti: "my personal view is that the overall assessment hasn’t changed much"). Even though this paper is too late for the IPCC AR5, I hope it reflects a change in thinking from the IPCC authors involved. (Notable also that Nic Lewis is involved.)
  
  The results are described in rather strange terms, considering what they have actually presented. They argue that the new result for sensitivity "is in agreement with earlier estimates, within the limits of uncertainty". But of course none of the published estimates are inconsistent with each other in the sense of having non-overlapping uncertainty ranges - no-one credible has excluded a value of about 2.5C, that I am aware of. The contrasting claim that the analysis of transient response gives a qualitatively different outcome (being somewhat lower than both the previous IPCC assessment, and the range obtained from GCMs) is just weird, since both their ECS and TCR results are markedly lower than the IPCC and GCM ranges.
  
  This looks like a pretty unreasonable attempt to spin the result as nothing new for sensitivity, when it is clearly something very new indeed from these authors, and implies a marked lowering of the IPCC "likely" range. Although the paper does not explicitly mention it, the "likely" range for equilibrium climate sensitivity using the full 40y of data seems to be about 1.3-3C (reading off the graph by eye, the lower end may be off a bit due to the nonlinear scale). So although the analysis does depend on a few approximations and simplifications, it's hard to see how they could continue to defend the 2-4.5C range.
  
  
  Source: James' Empty Blog
  

• 16.05.2013: Yet more sensitivity
  
  This really does seem to be the story that runs and runs...here's another article in the NYT recently, this time by Justin Gillis, who summarises my views accurately (take note David Rose)
  
  
  There is also this paragraph, which piqued my interest:

  Several scientists say they see reasons to doubt that these lowball estimates will in fact stand up to critical scrutiny, and a wave of papers offering counterarguments is already in the works. “The story is not over,” said Chris E. Forest, a climate expert at Pennsylvania State University. 

  I don't have any idea what the "wave of papers" is, although the recent splash about increased ocean heat uptake might have some impact. But several people - Forest prominent among them - have argued for some time that the models already take up too much heat, which suggests to me that while the new data on this might help to close the gap, it is unlikely to show models not mixing enough (which would be one route to arguing that sensitivity is actually high).
  
  Source: James' Empty Blog
  

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