Bishop Hill Pierrehumbert and unrealistic expectations
May 7, 2013 Climate: RC Climate: sensitivity David Appell has written a rather strange article, purportedly about climate sensitivity, but actually about individual components of the climate system. It's only at the end that the climate sensitivity question is addressed:
“There’s really nothing in [the recent temperature record] that changes our estimates of climate sensitivity.” Calculation of that all-important number from the 20th century record is not possible, because the aerosol forcing is not well known, nor are the data for ocean warming up to the task.
“Any estimate of sensitivity requires all of the record and not just the last 20 years of it,” Pierrehumbert says. “The smaller the piece of it you take, the less certainty you have in your result.”
Nonetheless, he agrees that earlier warming may have been deceiving.
“I think it’s true that some rather sloppy discussion of the rapid warming from the 20th century has given people unrealistic expectations about the future course of warming.”
This is rather odd, because the IPCC publishes estimates of aerosol forcing. They may be uncertain, but they are hardly unknown. It's also rather odd that flat temperatures don't, in Pierrehumbert's opinion, change estimates of climate sensitivity. I'm sure someone (Ed Hawkins perhaps, or was it James Annan?) said that flat temperatures could do nothing except reduce the value.
Moreover, I also recall that Forster and Gregory reported that aerosol forcing affected the uncertainty of their estimate of climate sensitivity but not the value. I think I am also right in saying that their method is unaffected by ocean heat uptake uncertainty.
That said, the unrealistic expectations of the future engendered by sloppy discussion of 20th century warming need to be more widely recognised, so it's good to see the case being made by an RC insider.
Reader Comments (36)
"“There’s really nothing in [the recent temperature record] that changes our estimates of climate sensitivity.”
And there never can be.
S.L.B.T.M.
"Mathematics" teaches us that we can't say if a thing is statistically valid or not unless we have a statistical model for the process we are studying.
The Met Office's embarrassment at being asked to explain their "statistically significant" statements arises from it having become apparent that they made their claim yet without having a validated statistical model for the climate process. Nor does anyone.
If "warming" means "it is getting warmer" then, in any normal use of language, the warming has stopped.
“Any estimate of sensitivity requires all of the record and not just the last 20 years of it,” Pierrehumbert says. “The smaller the piece of it you take, the less certainty you have in your result.”
Yes, this is exactly what Pierrehumbert and all the other members of the team said after Hansen's 1988 Senate hearing.
Shorter Pierrehumbert:
'Curses, they've found us out! That's another fine mess you've got us into, Mikey'.
“Any estimate of sensitivity requires all of the record and not just the last 20 years of it,” Pierrehumbert says. “The smaller the piece of it you take, the less certainty you have in your result.”
BTW, is anyone, anyone at all, saying that guesstimates of climate sensitivity should be based on only the last 20 years of temperature data? If they were saying that, then the sensitivity would be close to zero, wouldn't it? Is anyone saying that?
am I alone in detecting a trecnd in recent utterances by Pierrehumbert towards ...the sceptical....we just do not have enough data to say what is happening.
"It's also rather odd that flat temperatures don't, in Pierrehumbert's opinion, change estimates of climate sensitivity. I'm sure someone (Ed Hawkins perhaps, or was it James Annan?) said that flat temperatures could do nothing except reduce the value."
That is certainly true, with greenhouse gas concentrations continuing to increase, if all other factors are unchanged. But if you believe the IPCC's AR5 WG1 SOD estimates of heat uptake by the oceans etc, the rate of uptake has been much higher post 2000 than in previous decades. If real, that faster heat uptake can pretty much compensate for the global surface temperature standstill when it comes to estimating climate sensitivity using data from 2000 onwards as compared to data from the 1990s.
Is the increase in heat uptake real? That is unclear. It is not much evident in the Levitus 2012/ NODC 0-2000 m ocean heat content data. It is possible that the estimates used in the AR5 SOD are more accurate, but very far from proven. There are other estimates of the Earth's heat uptake in the 2000s that agree with the Levitus 2012/ NODC 0-2000 m ocean data (e.g., Loeb et al, 2012).
I can confirm that the Forster & Gregory (2006) method is unaffected by ocean heat uptake uncertainty.
A question from a non-native eenglisch reader:
Would you use the expression "give people unrealistic expectations" if it's something you fear, like catastrophic global warming? Wouldn't you rather use "unrealistic expectations" about something people hope will happen?
Nic Lewis,
"But if you believe the IPCC's AR5 WG1 SOD estimates of heat uptake by the oceans etc, the rate of uptake has been much higher post 2000 than in previous decades."
Anyone with a swimming pool in their garden can confirm that this is exactly how reality works. As the sun comes up, the air starts to warm. It feels warmer and warmer. This continues for a while.
Then, for reasons that are yet unexplained, the pool suddenly starts to suck heat out of the air, and the air temperature stagnates, even though the sun is getting higher and higher.
It's a well known phenomenon.
Bebben
"something people hope will happen"
But the warmists want it all to happen! Just not to them, of course...
thanks jamesp.
I also obviously read the post before I noticed the headline. And of course, climate folks prefer warm hangouts like Doha, Bali, Cancun... I guess Copenhaguen failed because of "unrealistic expectations".
:-)
Just posted this at the Yale forum (awaiting moderation)---
Re 15 years being “enough”…
From the Summary for Policymakers from Working Group I of the 2007 IPCC Fourth Assessment Report:
“Since IPCC’s first report in 1990, assessed projections have suggested global averaged temperature increases between about 0.15 and 0.3°C [0.27 and 0.54°F] per decade for 1990 to 2005. This can now be compared with observed values of about 0.2°C [0.36°F] per decade, strengthening confidence in near-term projections.”
If in 2007, 15 years of data were enough to “strengthen confidence”, what should 15 years of data do to our confidence in 2013?
Or is 15 years enough only when it’s…enough, and not enough when it’s…not?
The point is that it is impossible to calculate climate sensitivity unless and until everything is known and understood about natural variation and the upper and lower bounds of every constitute forcing therein. Until that knowledge and understanding is gained, it is impossible to seperate the CO2 climate signal from the noise of natural variation.
Since we do not have sufficient understanding of natural variation, including the extent of clouds, and, of course, aerosols, any assessment of climate sensitivity is presently misconceived and disengenuous.
Another problem is that pre 1940s warming appears to be down to natural variation. The only period when CO2 may have played a part was for the 20 year period between late 1970s and late 1990s. There was only 20 years of warming and if 20 years of data is not sufficient from which to draw conclussions, then there is insufficiient data to suggest that CO2 may be responsible for any warming.
The satellite data, which spans a period of 33 years, suggests that there is no correlation between CO2 and temperature (the temperatures are flat between 1979 and 1997, and again flat between 1999 to date; it shows merely a step change around the super El Nino of 1998 which event does not appear to have been caused by CO2). The satellite data suggests that climate sensitivity is so near to zero that no discernible signal can be seen.
Given the claimed residence of CO2, it is more significant that there has been no statistical warming these past 17 years or so (depending upon instrument data set chosen) than there may have been some warming for about 20 years between late 1970s/late 1990s. The so called basic physics would suggest that the CO2 forcing as from 1999 onwards is greater than it was as from say 1977 onwards such that the higher the concentration of CO2 in the atmosphere, the less likely that there would be temperature stasis.
I say 'may' have been warming during the late 1970s/late 1990s because one interpretation of the satellite data set is that there was no warming between 1979 and 1997 and that the warming seen in the land based thermometer record is nothing more than an artefact of poor siting, station drop outs, UHI and inappropriate adjustments, ie., the land based thermometer record is polluted by the foregoing factors and that in fact there was no warming (or only insignificant warming) during that period. If this is so, again, this would suggest that climate sensitivity is low.
But as I said at the outset, it is impossible to assess climate sensitivity until everything is known and understood about natural variation and gaining that knowledge and understanding ought to be the holy grail of climate science.
Bebben, Yes. “Trepidation” is a better description for fear of something that might happen in the future.
When the bad event does not happen, you might expect people to be very pleased, or at least mildly relieved. Yet strangely, many cAGW adherents seem to be getting even more agitated the longer we have to wait for disaster to appear on the horizon.
It is most peculiar. I am not sure if I can think of a good (non-medical) word to describe it in English. Perhaps "Angst" was imported into English for this purpose.
Further to Nic's comment (see May 7, 2013 at 10:45 PM | Nic Lewis)
"But if you believe the IPCC's AR5 WG1 SOD estimates of heat uptake by the oceans etc, the rate of uptake has been much higher post 2000 than in previous decades. If real, that faster heat uptake can pretty much compensate for the global surface temperature standstill when it comes to estimating climate sensitivity using data from 2000 onwards as compared to data from the 1990s.
Is the increase in heat uptake real? That is unclear. ..."
////////////////////////////////////////////////////////////////////////////////
One of the most fundamental problems regarding the ocean uptake conjecture is explaining the physical mechanism by which this is occuring.
In particular, what process is on going for say the period 1999 to date, which process was not on going during the period 1977 to 1998?
Has the radiative physics of CO2 changed during the past 15 or so years?
Can the so called basic physics of CO2 result in it sometimes heating the atmosphere and not significantly heating the deeper oceans, but at other times not heating the atmosphere but instead heating the deeper oceans?
What is about the so called basic physics of CO2 that caused it to heat the atmosphere say for the period 1977 to 1997 but then suddenly switch from heating the atmosphere to heating the ocean (more specifically the deeper ocean) after 1998?
Put another way, why was the deeper ocean not being heated during the period 1977 to 1997, and is only now (as from 1998) being heated?
May 8, 2013 at 1:44 AM | richard verney
As statistically-challenged as I am, far be it from me to even attempt to answer either phrasing of your question, Richard.
That being said, however, as a reasonably educated lurking layperson ... I have noticed that within the field of climatology (and Lewandowsky's specialty, the related field of psychoclimatology, come to think of it), there appears to be a predilection amongst these experts for ... well... for redefining words and phrases.
Consequently, the thought has occurred to me that perhaps a newer, truer meaning of "Global Temperature Anomaly" is emerging from the depths of post-normal science (in conjunction with post-modernist English) - and that this "redefinition" may account for the otherwise inexplicable conundrum you have articulated ;-)
Pierrehumbert is one of the few in the team with brains. Thus in his 2011 paper, which is worth reading**, he doesn't dwell on the Aarhenius mechanism which any professional with decent heat transfer knowledge immediately realises is bunkum. Instead he cleverly used the 'CO2 bite' in OLR plus slipping in the ludicrous claim that this accounts for a third of the GHE thus cleverly cementing in the public psyche the 134.5 W/m^2 created artificially within the models. However, he does this with quite clever weasel words.
The team is desperately defending the phoney heating caused by phoney boundary conditions. The claim that this is being put into the oceans because it doesn't appear elsewhere is based on 0.9 W/m^2 [2009 data]. However, they are really using this as a way of dragging the attention of the public away from a much larger error - where does the 134.5 - 0.9 W/m^2 go?
My point, that it never existed in the first place,is now ignored rather than being furiously countered with claims that Kirchhoff's Law of Radiation applies at ToA when it can't!
**PhysTodayRT2011.pdf
PS you can easily explain how the 'CO2 bite' is bypassed from the lower atmosphere.
@James Evans:
"Anyone with a swimming pool in their garden can confirm that this is exactly how reality works. As the sun comes up, the air starts to warm. It feels warmer and warmer. This continues for a while.
Then, for reasons that are yet unexplained, the pool suddenly starts to suck heat out of the air, and the air temperature stagnates, even though the sun is getting higher and higher."
The problem is that the heat in the oceans is actually missing, "and it's a travesty!". So the story was been that it has gone into the deep oceans where we can't detect it. This lasted for some time until it became clear that the heat had somehow managed to get into the deep oceans by avoiding the 3000 Argo buoys that measure the oceans down to 2000 metres. It's taken Trenberth a few years to come up with a new hypothesis which is that the heat is there, it's just not measurable because the oceans are so big. So here we have one of the heroes of the IPCC telling us on the one hand that the heat was concentrated and taken to the bottom by ocean currents, and on the other saying the heat is so dissipated it's not measurable. Does that sound like a credible scientist to you?
Climate sensitivity is something like how much temperature changes with a doubling of CO2 concentration.
The implication is changes in CO2 concentration changes temperature.
On 24 July 2012 in a lecture at Sydney Institute, Professor Murray Salby clearly demonstrated the widely held belief, promoted by IPCC, is wrong. It is not rising CO2 which leads to increased global temperature. Increasing temperature leads to rising levels of CO2. More importantly this rise in level of CO2 is due to natural not human activity.
The HockeySchtick has got it down to one graph
But if CO2 concentration FOLLOWS changes in temperature climate sensitivity is meaningless, one might as well look at how CO2 concentrations change with change in FTSE100 or length of skirts.
www.woodfortrees.org/plot/esrl-co2/isolate:60/mean:12/scale:0.25/plot/hadcrut3vgl/isolate:60/mean:12/from:1958
http://hockeyschtick.blogspot.co.uk/2013/01/single-graph-demonstrates-man-made-co2.html
jeremyshiers.com/blog/a-single-graph-shows-co2-does-not-change-temperature-change-may-2013/
So why are we talking about climate sensitivity?
As for Pierrehumbert, I believe what we're seeing are the first signs of equivocation. I believe the brighter ones having gone through the folie de pluseurs where the was certainty in everything they did are now wakening up to the fact that their certainties might just be wrong, and that there will the awful consequences when the politicos realise that they were overconfident in their predictions and projections.
As richard verney pointed out above, the correlation between rising temperatures and CO2 is only apparent in the record between 1970 and 1995, you would think wouldn't you that the scientific establishment would have take more caution than they did in announcing CO2 caused most of the warming. But they didn't and we are now facing power cuts and fuel poverty because their advice was taken by the politicos. The politicos will be wasted by UKIP at the European and General elections on two key issues, the EU and energy policies, and they won't like it.
May 7, 2013 at 10:45 PM | Nic Lewis
AND
May 7, 2013 at 10:54 PM | James Evans
//////////////////////////////////
Further to the above posts, I was unsure whether there was an element of sarcasm.
I have a swimming pool. It does not suck heat out of the air, although the air temperature acts to reduce the rate of .heat loss from the pool.
As a rule of thumb, my pool in winter adopts a temperature of about 1 to 2 degC above the night time lows. Where I am in Spain, winter night temperatures are rarely below 6 degC and thus the pool adopts a temperature of about 7 to 9 degC (typically).
In the summer months the pool temperature is about 4 to 7 degC above night time temperatures. It reaches a maximum of about 35 to 37degC. Night time temperatures are usually 27degC plus.
My pool has an almost East/West orientation, with sun on it all day long. The pool temperature is dictated by the sun, the length of sun up and cloud free hours.
If there is a bad spell of weather, say a week without sun, but the last couple of the days are particularly warm (say because of a warm wind blowing from the Sahara), the pool will cool down within 2 or 3 days but will not noticably warm up again during the last couple of days of the week even though the air is particularly warm during those days. It does not suck the heat out of the warm air.
However, with no noticable change in air temperature, if the sun comes out, the pool will warm between 2 to 4 degC a day. It is all about solar penetration.
PS. I usually go swimming around Easter (say end of March/early April). At that time of year, my pool is usually about 23degC. I have yet to go swimming this year. A few days ago, the pool was down to about 15.5degC. This week, we have had a couple of days of sun so it is probably now about 20degC. It May it ought to be more in the region of 25 to 27degC.
Like a lot of Europe, It has been very cold this year in Spain and much more cloudy than usual. For the majority of the first 4 and a bit months of this year, I would suspect that we have been some 4 to 6degC colder than the norm (and it has felt even colder than that due to cloudiness and strong winds).
Can anyone say 'climb down'? If RealClimate's Pierrehumbert says it and David Appell reports it, I think the die is being cast - that's what's going on here.
Does anyone recall the ClimateGate email about "what if we're [climate scientist's] wrong" about catastrophic alarm? "They'll probably kill us" was the mordant (or comic) response.
"Does anyone recall the ClimateGate email about "what if we're [climate scientist's] wrong" about catastrophic alarm? "They'll probably kill us" was the mordant (or comic) response."
I believe it was Ed Cook, who also said this about temperature reconstructions when discussing a new paper on uncertainties in them:
"7. Publish, retire, and don’t leave a forwarding address Without trying to prejudice this work, but also because of what I almost think I know to be the case, the results of this study will show that we can probably say a fair bit about 100 year variability was like with any certainty (i.e. we know with certainty that we know fuck-all)."
My favourite quote from this rather wonderful piece is from Ben Santer:
Please note that we are all being given permission to study the noise, for no extra carbon taxes or wind farm surcharges, by the great man. Human freedom has never, in my opinion, had such a champion as this.
It's not quite so clear if we are allowed to study the signal, because that costs real money. But why quibble. We wouldn't know the signal if it came along and hit us in the face - like a slightly stronger gust of wind, for example. That is why experts like Professor Santer exist, to tell us whether it was signal or just meaningless noise. This applies right up to the level of Hurricane Katrina and beyond. The bigger the better.
To take the most important example raised in this glittering tour de force, the increased uptake of heat by the oceans from 2000 is signal. Signal of a particularly powerful kind: pre-evidence signal. You need to be an expert to spot such a thing and the IPCC knows you're an expert because you spotted it.
We are in the presence of greatness and it's clear the author David Appell understood this. I can only weep for those like Richard Verney who think that the relevant data goes back to when the earth first had an atmosphere. Of course it doesn't. It goes back as far the experts say it does and no further. If they can even bother. They're simply too busy studying the signal.
Does that sound like a credible scientist to you?
May 8, 2013 at 7:15 AM geronimo
S.L.B.T.M.
@richard verney
Another good question is what started the 1910-1940 warming. And what stopped it?
A really good theory ought to to be able to answer this question as well as discuss the 1975 onwards period. And a good answer would be a powerful demonstration that it was on the right lines.
But all I have seen is a rather old, very handwaving paper about volcanoes and stuff.
Has anyone seen anything better?
If indeed this is a sign of equivocation on their part, I have a prediction. I reckon that the doubts expressed over certainty, over error bars, over unknowns unknowns and natural variation by people like us, ignorant sceptics and anti-science loons, those doubts will turn out to have been ill-founded guesses and the result of obstreporous intent. THEY will be correct in holding the same opinions, because THEY are the enlightened ones.
Heh, g, do you have any idea how many times I had to write 'last quarter of the last century' on the Blackboard?
=========
richard verney
"One of the most fundamental problems regarding the ocean uptake conjecture is explaining the physical mechanism by which this is occuring.
In particular, what process is on going for say the period 1999 to date, which process was not on going during the period 1977 to 1998?"
Very good questions. I'm not an ocean expert, but I've read claims that increased wind-driven mixing between mixed layer (surface down to between several tens of metres and over 100 m depending on location) and deeper layers is a major factor in increased ocean warming. The mixed layer is much warmer than (the mean temperature of) even the next few hundred metres. So, wind-driven mixing would warm the deeper waters but cool the surface mixed layer. When the, now cooler, mixed layer regains its original temperature due to heating by the sun, etc., that would lead to a significant increase in ocean heat content without any increase in sea surface temperature over its pre wind-mixed state.
Whether the wind-driven mixing mechanism is a major factor or not is another matter. As is the question of why it should be operating much more strongly since 2000 than in the 1990s. The explanation for the standstill in global temperature since the end of the 20th century may turn out to have little to do with ocean heat uptake.
Nic:
A sober and realistic account of the situation as usual. But here's another hard question. When will an explanation for the standstill in global temperature be forthcoming? Will we ever know the reason? How can we know when we'll know? To say I'm agnostic about such matters is to understate the case.
geronimo:
I appreciate your input, as usual, but, based on my reading of Richard Lindzen soon after leaving my mother's teat, I wouldn't put it quite like that. Lindzen speaks of a iron triangle of scientists, activists (such as NGOs) and policy makers. The scientists normally say something close to defensible, using crucial words like 'may' and 'possibly'. (A character like Mann in paleo being the exception that proves the rule.) Activists take those words, remove the equivocation and add whatever they feel is needed to reach the policy makers. Crucially the scientists seldom complain at this. And lo, the policy makers, among other things, channel more funding to the scientists.
So I'd expect Pierrehumbert has always known how uncertain the field he works in is. Whether he and others have acted with integrity as imminent climate catastrophe has been trumpeted in the media is another thing.
Richard:
"When will an explanation for the standstill in global temperature be forthcoming? Will we ever know the reason?"
A favoured explanation will probably be adopted by the mainstream at some point, but I'm not sure that we'll ever really know the reason(s) - the climate system is so complex and understanding of it is far from perfect.
I do think that in another ten years we'll have a much better picture of how much heat is going into the ocean - the Argo buoy network has been fully operational for well under ten years so far, and it had teething troubles. And if the temperature standstill were to continue for another ten years whilst greenhouse gas concentrations continue to rise, without a demonstrable compensating increase in the flow of heat into the ocean, then some serious rethinking would be needed.
Nic, the teething troubles you are talking about is adjustments to show warming. Why is it that warmists can't just take a simple reading off of a thermometer? They always need to adjust the reading, not a big confidence builder that this is accurate.
So it moves from catastrophe and worse-than-we-thought claims circa 2007, to arguments for why the theory hasn't been falsified yet, circa 2013.
@Nic Lewis: the serious thinking has already been done. Climate Alchemy creates a Perpetual Motion Machine of the 2nd Kind by incorrect boundary conditions in the models.The planet is self-controlling within very wide variation of [CO2], using it as the working fluid of a heat engine with null point being SW IN = LW OUT. There is no missing heat.
Looks like Ray and I rather mess with a bunch of peoples' conceptions of RealClimate. How about that, we're not all brainwashed automatons who will do anything for grant money after all.
For avoidance of doubt Jim there's one person on Bishop Hill - probably many - who does not hold that simplistic, arrogant and unhelpful view. The debate is too often led by those with the most extreme things to say. It remains a pity for me that RC didn't open up to Steve McIntyre long ago, however. That would have given the centre ground much more power.