Climate sensitivity is 5.3C?

Too late for an April Fool, my eye was caught by this headline in the Guardian:

Global warming may be far worse than thought, cloud analysis suggests

 With the article itself containing the odd phrasing:

Researchers said that a doubling of carbon dioxide in the Earth’s
atmosphere compared with pre-industrial times could result in a global
temperature increase of up to 5.3C – far warmer than the 4.6C older
models predict.

4.6C seems a strangely high value to start with, it's some way from any consensus value (and it's not even the upper end of the oft-quoted undcertainty range of 2-4.5C).

Sadly, the paper is paywalled, so I can only see the abstract. But it seems that the authors are arguing that models have a bias in the way they represent clouds (too icy, not wet enough), and correcting this bias will shift their sensitivities up a bit. 4.6C is the most sensitive model in the AR4 and it seems to get shifted up a smidgin to 5.0-5.3C (there is presumably some uncertainty in the adjustment to each model). The paper also says the sensitivities shift by "up to 1.3C" which must therefore be the largest potential shift of any of the models, and probably some way above the mean estimated change. It doesn't look like such a revolutionary change as to justify the headline, even if one accepts that the result is right.

Of course, if the models were more sensitive, it would (other things being equal) result in greater warming not only in the future, but also in the past. Which would make it more challenging to reconcile with what we've observed. Kevin Trenberth (who has presuably seen the whole paper) doesn't seem that impressed. Maybe I'll manage to find a copy somehow...

Update: seems like several others have weighed in similarly (Gavin, ATTP). The Yale puff piece is particularly misleading, constrasting the old 2-4.6 model range with a new range of 5-5.3 which is surely nonsensical. Even without reading the paper, it's obvious enough that 5-5.3 does not represent a new range that would contain all the models, since they only move by "up to 1.3C". I'm fairly confident that my interpretation above must be correct.

I don't want it to sound like I'm determined to reject any attempts to change our estimate of sensitivity. But any substantial changes will have to be supported by significant evidence to overturn the weight already accumulated. In this case, what I'm really objecting to is the hyped-up presentation of what is actually a pretty small change anyway.

GingerGhost

Lovely GingerNuts only lasted 3 weeks before a GingerLady came and took him away to his new life hunting GingerRabbits around the legs of the GingerHorses on a farm deep in the Lune Valley.  All is well, but when we got the cats back from the rescue after Easter we found that GingerNuts' ghost had somehow stowed away with Spice and Pepper:

Being much lighter than GingerNuts, GingerGhost floats around the furniture, and has a tendency to waft to the top of the house. He's friendly, nimble and elegant, and Spice and Pepper are a lot less bothered by him than they were by his predecessor.  Can't say more yet as I haven't played with him much due to being down with 'flu for the last few days. 

He was originally called GingerTip at the rescue, but maybe that was a made up name. They changed his name to Benson, because he, apparently, likes the bed. We don't let the cats in our bedroom. Hope this won't be a problem; he seems to have taken well to the upstairs sofa instead. But, does this mean I have to rename him　横浜ワールドポーター (Yokohama World Porters), which is where we bought that sofa? 

[jules pics] Yet more Blue Skies!

Windows done, James is making the most of the luxury scaffolding to practice his lime mortar pointing skills. Last week was too cold, then it was too wet, and now, apparently it may be too warm and dry, in which case I'm not sure quite which day of the year would actually be OK for this temperamental task! Anyway, he has no choice, as we can only keep the scaffolding up a bit longer. At least, with all this good weather, he can do some Blue Skies Thinking while he is up there... 

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Posted By jules from jules' pics.

3D Impossipuzzles

In its own way, Yorkshire culture is as crazy as Japanese culture. Today's cultural exercise was doing an impossible 3 dimensional puzzle halfway up a mountain (Ingleborough), in the rain. It was also quite cold (the ground was hard with ice as we set off up the hill) although it did warm to a few degrees above freezing later on.

The game starts with a drystone wall. This is a wall of rocks which have been shaped by nature, and which contains no mortar. Clearly such a wall is physical impossibility but in Yorkshire these walls are everywhere and they magically stand up all on their own for hundreds of years. But sometimes the magic spell breaks and this causes part of the wall to fall down. The puzzle is to fully take down the wall and rebuild it using the pieces strewn around your legs so that it will stand for another 200 years or so. The original magic spells seem to have been lost, so modern woman has to achieve this using 3D puzzling. I was very surprised that most of the rocks are quite light so this is a sport which anyone who can stand the cold and rain can take part in. The main skill required is that of mental rock spinning. I've had so much practice packing our van with boxes in the last couple of years that I found this part came quite easily, but it was certainly tiring both physically and mentally. 

This photo was taken when we had almost finished for the day. Our section was not quite complete, but we seemed to have made fairly good progress, although one of the other teams had a much more difficult challenge as they were building on a very steep slope.

Picking up strewn rocks to put in wall... James works hard while the gurus give sage advice.

This is our bit of wall from the side. At the end of the day, our guru pointed out how it could have been done much better - there were many errors! But he also pretended that he wouldn't be out tomorrow to take it all down and redo it, stating that, despite all our errors it "would stand". That's nice - at last we've made a real contribution to something in the world!

The day included traditional Yorkshire feasting: sandwich and a thermos, at a slightly less windy spot.

windows

Spent the week in the cat room. It has been quite exciting, especially on Tuesday afternoon, when, through the miracle of Skype, we were transported to a meeting room in Reading University to discuss paleoclimate research with some colleagues. Hope they enjoyed the occasional cat appearance. 

The reason for our retreat is windows, or rather, the hole created when a window is removed. Our house has a lot of windows, and all the topmost ones were all poor in some way. Some were cracked, some failed double glazing, some single glazed, and one was opaque for no reason we can comprehend. Rapid progress has been made. There are to be 15 new panes in total and just 3 still to go - the hard to access ones s behind the stove. Still, they have a nice day for it today with only a couple of inches of snow on the ground! The window peoples do just one window at a time, but one window-sized hole in your open plan living area is enough to make you switch off the central heating and retreat to the cat room with its electric storage radiator and supplementary electric heater. It's been quite snug. 

The scaffolding went up at the weekend, and we will keep it up for a while to repoint the upper levels (hopefully it will warm up a bit next week to make this possible). Here are the window peoples (Touchstone Glazing) working on a hole.

And here's a hole where there used to be a failed double glazing unit and is now a lovely new one.

Ten thousand pounds is a lot of money to spend on improved transparency. The previous occupants had done some not very good artwork as well as stuck some transfers on several of the windows to simulate stained glass, so we thought give ourselves something to remember and put leaded lights in the holes where that had previously been decorated windows. Ultimate vanity this, as the images are adapted from my photos. Left to right, top to bottom, Pen-y-ghent, Ribblehead viaduct, Scaleber Force, and Ingleborough. Pen-y-ghent with its bright sun faces east, and  Ingleborough is in the south at the west end of the building, where the setting sun catches the light - which is why we made a sunset image. It seems to work - it was glowing very nicely yesterday evening. These leaded lights are double glazed units, with a leaded glass pane stuck in the middle, so sort of triple glazed I suppose.

BlueSkiesResearch.org.uk: Could the Pliocene constrain the Equilibrium Climate Sensitivity?

The long-awaited prequel to "Can the Last Glacial Maximum constrain climate sensitivity?" is now up on CPD and open for comment. This latest episode is set back in the mid-Pliocene warm period 3-3.3Ma BP (MPWP, sometimes also called mid-Piacenzian by people who care deeply about the conventions for paleoclimate nomenclature). The particular reason for looking at the MPWP is that it’s the most recent period when CO2 was relatively high (at least compared to pre-industrial, though perhaps not so high compared to today) and the climate was correspondingly warm. This means that it avoids some of the major complications that arise when studying the Last Glacial Maximum, where there is the question of how directly a strong cooling informs about a strong warming, and large ice sheets provide a substantial forcing to the atmosphere-ocean system that does not necessarily combine linearly with other forcings such as GHGs. Thus, PlioMIP was born around 2009, and by 2015 lots of different modelling groups had produced simulations of the MPWP to compare with each other and with the data assembled by the USGS. Being much further back in time than the LGM, the data are much more sparse (even though the interval of time is also far broader) and more uncertain. Also, the boundary conditions such as atmospheric CO2 level are not known with great precision. One might be suspicious that choice of value used in the simulations, 405ppm, could have been been influenced by political considerations :-)

Although theres been a fair bit of analysis of the model results, no-one had looked directly at how the simulations depended on the equilibrium climate sensitivities of the models. So we did the usual thing, of comparing the tropical temperature change at the MPWP, to the equilibrium sensitivity of the models. It looks like there might be some sort of relationship there, though it’s far from certain.

Here’s the main result, with the model results represented by red dots.

The temperature data for the MPWP is a bit less well developed than for the LGM, so we didn’t really have a good uncertainty estimate but instead just tried a few possible values as a sensitivity test. It is also notable that the model ensemble seems to generally show more warming here than the data, although with substantial overlap if uncertainty is taken into account. It is possible that the forcing is too strong, or that the models are too sensitive in this region, or it may be that the data are wrong, or to be more precise, misinterpreted in terms of climate. I try to be avoid saying things like "the data are wrong" especially when talking to the data specialists, as at some level the data are definitely correct, real stuff has been measured and the measurements themselves are not in any real doubt. It’s how these real measurements are translated into a putative climate variable that is where the difficulties lie. Another interesting and possibly disconcerting aspect of this result is that the regression line does not pass through (or close to) the origin, implying that a hypothetical model with zero sensitivity to CO2 would show a significant tropical cooling at the MPWP. It is hard to see how that might arise, although it is also hard to see how a model with zero sensitivity to CO2 could arise anyway. It is perhaps not completely impossible that increased latitudinal transport would result in a tropical cooling accompanied by a high latitude warming so as to cancel out the change on the global average. After all, there has to be some explanation as to why a small change in model sensitivity seems to correspond to such a large change in MPWP tropical warming in this sample. We've presented this work a few times and no-one has come up with any great ideas about it.

Anyway, we don’t have any strong conclusions, it might be possible to generate a meaningful constraint out of this, but we don’t have any real confidence in the specific result presented here. PlioMIP2 is being planned, with various improvements over the original PlioMIP. Most importantly perhaps, the researchers are aiming for a true "time slice" in which orbital and other forcings are near enough constant (and so, hopefully, the climate was in some sort of equilibrium with this), rather than aiming for some sort of average over the warm peaks within a longer interval, as PlioMIP did. The main problem with this is that the data become even more sparse, but it should in principle enable a more meaningful model-data comparison. Watch this space!

No, Terence Mills does not believe his “forecast”

Another day, another bit of clickbait climate sceptic trash in the Times. Hidden behind a paywall, which saves you from having to read it, though some of it is republished here and the underlying report (not peer reviewed) is on the GWPF site here. The basic premise is that if you fit a nonsense model with no trend or drift, you generate a forecast with no trend or drift (though with huge uncertainty intervals, necessary to allow for the historical warming we've already seen). Amusingly, even with those huge uncertainty intervals, the temperature is already outside them as tweeted here by Gavin.

I was interested in whether the author really believed it, whether he'd been conned or misrepresented by the GWPF, or whatever else his explanation might be. So I emailed him, proposing a simple bet: for every month where the temperature lies above the red 50% line, he pays me £50. For every month where the temperature lies below the line, I pay him £60. Expected win for him: £5 per month, indefinitely. Assuming he believes the forecast, that is. Expected win for me, knowing his forecast to be junk: £50 per month, though I might lose a few at the outset :-)

There followed a fruitless exchange in which he declined to comment on whether he thought the forecast was credible and refused to even discuss any possible bet. I'm still baffled as to what might motivate a statistics professor to put their name to such obvious drivel, it's hardly something that will enhance his reputation in the academic community, or that he can feel proud to have written.

sunshine and BlueSkies

In January there was one day of blue skies and sunshine when it did not rain, so on that day we cycled to Kirkby Lonsdale for breakfast (Kirkby Lonsdale is very 21st century - they let you eat breakfast until noon!!!). Stupidly I did not take a camera. In February it has also rained a great deal. For example, on Sunday we did a fell race in the wind and rain and mud. Running is probably one of the better things to do in the rain, but it was still unpleasant. However, it is hard not to feel an immense sense of glowing achievement just for completing such a stupid thing. Then yesterday it dared to be sunny when I was too tired from the race to go on a long ride. Very annoying. The whole point of BlueSkiesResearch is that we can go and research the blue skies when they appear rather than being stuck inside staring sadly out of the window. Unbelievably, today it also dawned bright! We cycled one of the several off-road routes to Litton, and this time did not forget a camera.

And to prove it was also sunny at home... one of GingerNut's main hobbies is seeking out sun patches. Presumably he does this in order to make his fur look as orange as possible.
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Posted by jules from jules' pics.

"If I was better at mathematics I would have liked to have been an engineer."

Spotted by chance, and the article is mostly irrelevant but I did like the refreshingly honest quote from a fund manager who has woefully underperformed the FTSE over the past 5 years, no doubt drawing a massive salary in the process.

There are those in the skeptic community who argue (based on who knows what, salary perhaps?) that scientists are basically the dregs left behind once the financial parasite industry has skimmed off the cream of the crop of the university leavers. This wasn't my experience, as in fact the top few in the year mostly queued up for the handful of DPhil grants available, but it's a good shtick to beat climate scientists with.

Ginger Nuts

When stocking a pond, it is usual to consider inches of fish. The inches can be in many little tiddlers or a smaller number of bigger fish. It turns out that the same applies to cats, only you measure it in feet rather than inches. Spice and Pepper didn't find their new home yet and were a bit lost in our large pond of a house. So we asked the cat rescue for some more feet of cat. His name is not actually Ginger Nuts, but Hobbes. But he is definitely a lot of feet of cat. 

A weaponised marmalade seal pup, his purr is a husky breathing sound. When he kneads, it is a real massage. He actually likes to have his tummy tickled (which is quite rare) but one mis-stroke and his tendency is to bite and swat. Thwap! He likes playing games too, in between the hours spent plotting our deaths. Of course, all cats spend much of the day plotting the death of their human parents, whether foster or adoptive, but it is a little more concerning when the cat is over 6kg of enthusiasm.  Now I know why tigers are so dangerous to keep as pets. Well, at least he doesn't have to choose which of us to sit on - on the sofa he can easily spread across both of us. 

So now we have Ginger Nuts, Ginger Tits and Poppet staying in our cat pond house. Funny how quickly cats lose their names (...should be Ginger Wot-No-Nuts? of course).