Bishop Hill Stern's nut graph
May 17, 2012 Climate: WG2 We had an interesting chat a couple of weeks ago about the way the noble Lord Stern had portrayed the effects on climate change on wheat yields. However, alongside his wheat graph is another graph portraying a similar effect of raised temperatures on ground nuts (click for full size).
;)
The cited paper, Vara Prasad et al (2001), is not online, but the abstract is here. Unlike the wheat paper, Vara Prasad appears to look only at the effects of temperature on groundnuts and Stern's graph seems to reflect the abstract pretty much exactly.
One question that occurs to me, based on the abstract, relates to the temperatures applied to the plants. Apparently, elevated temperatures were applied during the daytime. Of course, temperatures are not constant over the course of a day - they start and end the day much lower than the midday maximum. I wonder therefore whether the experiment was realistic to the extent that it reflected some kind of a daily temperature profile. Presumably the effect of hitting temperatures of say 38°C for a couple of hours in the middle of the day is different to a 12-hour baking at that temperature. Without seeing the full paper it's hard to reach a conclusion.
Despite the Vara Prasad paper not looking at the effects of CO2 on peanuts, this is still a question that is worth examining. Fortunately, there is the excellent CO2Science website, which collates the results of studies into this question.
Here's the page for peanuts.
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300 ppm
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600 ppm
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900 ppm
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|
| Number of results |
38
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|
1
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| Arithmetic mean |
60.3%
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35%
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| Standard error |
16.1%
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0%
|
It looks as though there is a very strong compensatory effect from carbon dioxide fertilisation.
Reader Comments (84)
O/T but a nutty report that the Guardian is already covering as well. CAGW is "OFFICIAL":
17 May: iTWire: David Heath: Its official - climate change is human-caused
Having exhausted all other possible causes, Melbourne University researchers conclude that the dramatic increase in local temperatures over the past 60 years can only be human-caused.
A team of over 30 paleoclimatologists has spent the past decade examining natural records of climate including recent geologically preserved sites along with written records (eg newspapers) and other data (corals, tree rings and Antarctic ice cores amongst many others) to construct a detailed view of climate changes in the Australasian region over the past 1000 years.
Lead researcher, Dr Joelle Gergis from the University of Melbourne saidsaid the results show that there are no other warm periods in the last 1000 years that match the warming experienced in Australasia since 1950. This period far exceeded the magnitude of warning in the so-called "Medieval Warming" period of 1238 - 1267...
According to the research team, the climate reconstruction was developed using 27 natural climate records calculated in 3000 different ways to ensure the robustness of the conclusions...
A PDF of the paper published in the Journal of Climate is available here for a fee.
The research will form the region's submission to the 5th IPCC climate change assessment report chapter on past climate due to be published toward the end of 2014.
http://www.itwire.com/science-news/climate/54765-its-official-climate-change-is-human-caused
Idso showed quite some time ago that the dangerous position is temperature increases without increases in CO2. With our CO2 gently increasing we have nothing to worry about for a little warming, and it will be protective if there is subsequent cooling as well. Higher CO2 levels are an unmitigated good, whatever happens to temperature and precipitation, as they desensitize to these other stress factors. Remember that C3 photosynthesizers are under stress due to currently fairly low levels of CO2.
Sorry for OT and to continue on pat's theme, but it has to be said that Dr Joelle Gergis assertion that
is complete bollocks. Not because CO2 is or is not the only explanation, but because there has not been any significant warming in Australasia since 1950.
Well, not until NOAA and Hansen came along and tampered with the data: http://notalotofpeopleknowthat.wordpress.com/2012/03/15/an-adjustment-like-alice/.
The late John Daly's summary also casts doubt on the assertion that there has been any warming in the region:
http://www.john-daly.com/stations/stations.htm#Australia
So this is just more post-normal paleoclimatological bollocks, just in time for AR5.
[Trolling]
There are so many results for a 300ppm increase in CO2 presumably because it represents a doubling of pre-industrial atmospheric concentration.
Are politicians wilfully blind to the fact that plants just plain prefer it warm and CO2 rich, (as it was in the pre-Quaternary when their physiology evolved) and the glaringly obvious future crop production benefits?
It is well established that the direct physiological effects of CO2 on plants may well offset the impacts of warmer or drier conditions to some extent, but the CO2 Science website seems to focus on studies of plants subject to elevated CO2 inside chambers which are either totally enclosed or enclosed around the sides but open at the top. This makes conditions a bit artificial.
There is another technique called Free Air CO2 Enrichment (FACE) which uses plots of diameter 1m to 25m out in the open air, with CO2 released around the edges so that it flows across the plot. This is more realistic as it exposes the plants to more natural environmental conditions, eg: actual weather.
While FACE experiments do confirm that CO2 physiological effects are real (stimulating photosynthesis and increasing water use efficiency), the overall beneficial effects on crop yield in FACE experiments tend to be smaller than in chamber experiments. There's a very useful open-access paper on this topic here.
The other thing to bear in mind is that we are uncertain of how much warming we'll get for a given CO2 rise because of (a) uncertainties in climate sensitivity and (b) the fact that there are other greenhouse gases other than CO2 (such as methane), which cause warming but don't fertilize photosynthesis or increase water use efficiency.
If climate sensitivity is low and most of the GHG forcing comes from CO2 then the beneficial effects of CO2 physiological effects may be relatively strong.
However, if climate sensitivity is high and/or the relative contribution of non-CO2 gases to the GHG mix is high, then we'd get more warming for a given rise in CO2 and hence the beneficial effect of CO2 physiological effects will be relatively less.
I may be oversimplifying your very nicely put point Richard, but the gist of your comment is that the effects of CO2 rising are in all cases positive, but not necessarily large in impact, depending on how the other factors fall out. Do I understand you correctly? If so would you agree that the original graph in the Stern report could be regarded as misleading, (even though there may be no argument over what the original paper said) in that it rather baldly presents a rise in CO2 as a dramatically bad thing?
Pat
>the so-called "Medieval Warming" period of 1238 - 1267
That seems awfully precise, but perhaps they got the dates from the newspapers they were looking at...
CO2 climate sensitivity is probably much less than claimed by the IPCC. It's not just me stating it. Much more post 1990's warming has been natural than the IPCC claims. The key evidence is this: http://bobtisdale.files.wordpress.com/2012/01/figure-102.png
Later data show the trend continuing. You can't get such cooling by GHG-AGW. The real explanation of the Arctic melting, now freezing, a 70 year cycle will be published. It does not involve GHGs.
"the climate reconstruction was developed using 27 natural climate records calculated in 3000 different ways to ensure the robustness of the conclusions..."
What is "calculated in 3000 different ways" supposed to mean?
Has anyone told them it doesn't matter what order you add things up?
Richard B
Thanks for the link to the FACE experiments. While the yield increases weren’t as much as expected, they do say that “elevated CO2 improves nitrogen use efficiency and .. decreases water use at both the leaf and canopy scale”, so you get some yield increase and with reduced inputs. Hard to see a downside there...
Richard
Wiki on FACE:
Cumbrian Lad, James P, Bish,
Yes, even though FACE expts show smaller yield increases due to CO2 than chamber expts, they do still show a beneficial effect.
I am not at all dismissing the beneficial effects of CO2 acting directly in plants - to do so would be missing out an important part of the picture.
We include CO2 fertilization and stomatal closure in our climate model.
Keen gardeners have noticed that plants grow a lot faster in a glasshouse. They don't waste time and effort submitting this knowledge to peer review to frame their evidence-led buying policy. They just do it, regarding the phenomenon as, for what it is termed down at the allotment, "the bleeding obvious".
tall human beings also have less protein and more scaffold it is about scaling factors
fact remains: more CO2 =>more plants =>more food =>more space.
Filbert,
This link for clues to develop allotment wisdom into a proper modern 'ology.
http://mysite.verizon.net/erickrieg/pedantic.html
"plants grow a lot faster in a glasshouse"
Especially if you pipe in CO2. Tomato growers often raise the level to around 1200ppm to maximise yield - if it didn't, they wouldn't.
@Alan Reed
Splendid link!
@jamesp
Owd codgers also know that when water supply is adequate, you can raise temperature and CO2 conc. until light intensity limits photosynthetic rate.
This is not about groundnuts, this is the replay of the Garden of Eden myth. Humanity is fine as long as we doesn't eat the apple, because then we acquire the knowledge to create evil things such as industry and capitalism which have negative impacts on the poor non-apple-eating noble savage. Oh, give us climate justice, please!
The mantram of the typical non-producing NGO-style Green/Left individual with regard to capitalism is: "If you can't join them, beat them."
Dr. Betts -
"there are other greenhouse gases other than CO2 (such as methane), which cause warming but don't fertilize photosynthesis or increase water use efficiency....if climate sensitivity is high and/or the relative contribution of non-CO2 gases to the GHG mix is high, then we'd get more warming for a given rise in CO2 and hence the beneficial effect of CO2 physiological effects will be relatively less."
The relative contribution of non-CO2 gases seems limited; the data which I have to hand indicate that, in 2010 relative to a 1958 baseline, approx. 66% of the GHG forcing is due to CO2, with most of the remainder due to CFCs (13%, currently not increasing) and to CH4 and N2O (14% taken together; CH4 growing slowly). A rough extrapolation puts about 80% of the current growth rate in GHG forcing down to CO2.
While agricultural effects due to, say, increasing CH4 may be purely negative, the fact of the matter is that the policies under consideration are to limit CO2, not CH4. So while CH4's effects may be of scientific interest, unless circumstances change, those effects are not of great political interest. Should the effects increase, one can consider whether mitigation of other greenhouse gases in a cost-effective manner; but to date, all efforts have concentrated on CO2 and what seems to be cost-ineffective approaches.
Efforts such as Stern's to inflate the negative aspects of "plan A" (business as usual), only serve to make one more skeptical of the actual cost-efficiency of "plan B" (mitigating CO2).
Uncertainties? No, no, no -- the science is settled. There should be no more debate.
We know this from constant media barrages from the likes of the EPA, and Al Gore, and the 97% consensus.
I bet Lysenko wishes he were alive today, what with all the nice trips to Hawaii, Bali and Gstaad, not to mention the Nobel Prizes and what-not.
Hmm, so instead of CCS, we should be piping all the CO2 from coal and gas power stations to the surrounding farmland to fructify the fields ? I wonder how many acres per typical 500MW plant ?
..I would do the calcs myself, but I have'nt got an envelope handy.
@HaroldW
AFAIK - the carbonistas regard CO2 in agriculture as neutral in the carbon cycle, unlike CH4 and N2O that occupy the rungs of the agriculture abacus, in whatever version it is, as CO2 equivalent values per unit of production.
The climate modellers must have been stung by criticism from agricultural scientists from all disciplines, to the extent that they are rejigging the carbon calculators to accommodate carbon sequestration by soil and vegetation and emissions under land use change and management, so that the models bear a faint resemblance to reality. When - wait for it - AFOLU (agriculture, forestry and land use) is in the frame we may find that emissions calculations for food are not just wrong, but very wrong, and for some foods in certain agricultural systems, even have the wrong net sign.
BH, the Prasad paper is online here:
http://www-personal.ksu.edu/~vara/prasad-pvv-ajpp01.pdf
Daytime temperatures were constant. This means that the Stern Review's caption was slightly wrong. The graph showed changes in 'crop yield' (actually fruit-set) not 'with increases in daily maximum temperature during flowering' but with exposure for one 12-hour day to various temperatures. (The study looked at longer exposures but the Stern graph showed the effects of high temperatures for one day at anthesis. Incidentally, it was slightly mis-plotted. The dot for 33 deg C was placed at about 33.5 deg C.)
So the graph is more worrying than Stern said it was - or it would be if, as you suggest, they had mimicked a more natural temperature profile and if they had used a more typical groundnut variety (they chose one that is particularly sensitive to high temperatures).
It is all about money.
How much money does Stern (and his collaborators) hope to make out of his nonsense?
It appears to me that elevated CO2 crop enhancement, instead of being welcomed, is an inconvenient embarassment to CO2 mitigation advocates, to be concealed from public awareness as much as possible, or failing that, desparately seeking reasons to downplay it.
Read what is presented as a summary of it in this tale of woe prepared by the massed ranks of our officialdom for MP's consumption, and weep
www.parliament.uk/briefing-papers/SN03763.pdf
May 17, 2012 at 3:49 PM | Filbert Cobb
Hi Filbert,
We're not "rejigging" anything - we've included CO2 fertilization into our models ever since we started modelling the carbon cycle - for example, see this paper of mine in Nature from 15 years ago.
The idea that CO2 fertilization is somehow "ignored" by climate models is a total strawman put about by propagandists like Heartland.
Cheers
Richard
OK, my envelope says a 500MW station produces enough CO2 to significantly benefit c 50 square miles of cropland.
@Richard, I am aware of face studies. I am also aware that they are not as realistic as you imply.
See
Holtum, J.A.M. and Winter, K. 2003. Photosynthetic CO2 uptake in seedlings of two tropical tree species exposed to oscillating elevated concentrations of CO2. Planta 218: 152-158.
Free-Air CO2 Enrichment (FACE) studies of the effects of elevated levels of atmospheric CO2 on the growth and development of plants have long been considered to be the most realistic experimental route to determining the likely biological consequences of the ongoing rise in the air's CO2 content, providing minimal alterations to the natural environment of the plants being studied. Now, however, this assumption is being called into question, as concerns are being raised about the possible physiological impacts of rapidly fluctuating CO2 concentrations that occur in response to the over- and under-shooting of targeted plot CO2 concentrations as the FACE apparatus continually adjusts to counteract the concentration-perturbing consequences of variations in wind speed and direction.
Holtum and Winter conclude their paper with these words: "our observations raise the possibility that FACE systems may underestimate the potential fertilizing effects of above-ambient CO2 concentrations on plants."
I do hope that this uncertainty will be reflected in your AR5 chapter
Cheers,
Don
The reason behind Stern's outrageous massaging of data is that the windmills are needed desperately to make carbon a new commodity to underpin the Euro in the absence of Eurobonds, which process would require a political solution. The failure of O'Barmy's cap and trade scotched the same for the putative Amero which is designed to replace the $US when it fails.
So, Stern and many in government are stooges of the banks and the hedge funds who want a replacement for mortgages to impoverish the people for vast private profit. This is why the disastrous German windmill plan was implemented without professional engineers in the decision making. The German power grid is near collapse. Merkel has just sacked the idiot lawyer who did it in a year: http://www.spiegel.de/international/germany/chancellor-angela-merkel-sacks-environment-minister-norbert-roettgen-a-833614.html
RWE and E.On have run out of capital, 2 million Germans have no electricity because they can't pay the high costs. As in the UK, green zealotry overrode engineering pragmatism.
The CEO of our National Grid Company has been warning of disaster as the Mafia trash our country with windmills which unless used with pump storage produce more CO2 than without the windmills.
robbo
500MW electricity output from natural gas would require 833 MW combustion energy (60% efficiency plants)
natural gas has a combustion content of 1000 btu per cube feet, or 1.05 MWsec per 0.0283 cube m,
or 37.1 MWsec per cube m gas
so your 500MW plant would consume 833/37.1 = 22.45 cube m gas per sec
or 1.94M cube m gas per day
1 cube m burnt natural gas produces 1.8kg CO2
so your plant would produce 3.49 Mkg CO2 per day or 3500 ton CO2 per day
this polish link shows an investment of 70 ton CO2 per year per ha tomatoes I think
which leads to a 20% increase in tomatoes from 400 to 480 ton per year per ha
so your plant would service 50 times 365 = 18250 ha or about 20 sq km tomato fields
well within the capacity of farmlands in spain or greenhouses one can see in the canaries etc
PRIVA company and GE energy Jenbacher (both very badly documented) seem to sell some stuff
It is heartening to see what the EU is doing on this, lol
after all the billions and billions of Common Agricultural Policy we have very very rich farmers all with triple chins doing very little on this.
fossil fuels power stations produce hot water as well, which can be used to heat greenhouses.
(not that this is now done across the board, our farmers just fetch the check at the post office I think)
behind the turbine water is still at a 80degrees+ hot enough for domestic heating as well btw.
this is why the soviets wisely built their nukes close to city centres, this way they could provide FREE heating to their city populations. We do not need that, as our establishment just gets the check you know, if they can take time off filling out their expenses.
I wonder what heated greenhouses will use when it all will run on windmills, lol
A team of over 30 paleoclimatologists spent the past decade examining research and found that there are no other warm periods in the last 1000 years that match the warming experienced in Australasia since 1950 ?????
Well this non-paleoclimatologist spent 1 minute visiting www.co2science.org and found 6 papers that say otherwise.
@Richard Betts
"We're not "rejigging" anything" - I hope you are not wilfully misconstruing my comment in order to intoduce a reference to Heartland.
"The Agricultural Greenhouse Gas Platform is a partnership of 16 organisations which aim to produce a revised set of methane and nitrous oxide emission factors for a range of agricultural systems and identify suitable sources of farm practice data to improve our reporting." - from AGGP's recent position statement. The Agricultural Greenhouse Gas Platform includes as partners, among others, The Met Office and UEA.
It continues ... Its new research programme funded by Defra and the devolved administration governments, includes in its remit accuracy, resolution of reporting system, evidence on emissions, statistics relevant to changing farming practices in the UK. It will provide evidence for a UK specific method of calculating CH4 and N2O emissions reflecting adoption of mitigations, enabling forecasting, monitoring of performance against targets of CCA 2008. Builds on previous knowledge, modelling, data sources to fill knowledge gaps.
Unfortunately, the way that agriculture’s emissions are reported globally in the GHG inventory does not
reflect many of the benefits that farming can bring (e.g. by storing carbon in vegetation and soils, or by
contributing low-carbon energy services to other sectors).
Now call me old-fashioned, but this is another way of saying "rejigging".
"propagandists like Heartland"
I hope your politics aren't affecting your science. ;)
Andrew
May 17, 2012 at 4:45 PM | Don Keiller
Hi Don
Thanks, yes, I realise that FACE is still not a magic solution. Thanks for being willing to be an AR5 reviewer - I encourage you to check our discussion of this issue!
I can't remember if I told you this or not, but for details on how to take part in the review process you need to email the TSU at tsu@ipcc-wg2.gov . I'd recommend doing it soon, so there is time for the TSU to send out the details to you in advance of the review start date of 11th June. The review closes on 6th August.
(I can't put your name forward myself - reviewers have to self-nominate as opposed to being recommended by authors!)
Cheers
Richard
Filbert Cobb
Ah, sorry, sounds like I may have mis-understood who you were talking about when you said "climate modellers". I thought you were referring to GCMs (which now include the carbon cycle) but your later post is referring to something different, I think. Sorry for any confusion.
I do agree that CO2 effects are not always taken into account in impacts studies (which use separate models from GCMs)
Cheers
Richard
May 17, 2012 at 6:19 PM | Bad Andrew
Not at all :-) I challenge anyone to tell me that Heartland are not predominantly about propaganda! Their NIPCC reports give the impression that CO2 physiological effects are completely ignored by mainstream climate science, which is simply not true, even though (as I said) some impacts studies do (sadly) ignore or downplay it - but that's not representative of the whole field.
Cheers
Richard
@ptw
Many thanks for doing the calculations.
I live in a country where power stations' waste heat is used for heating homes. It just seems logical to use the co2 waste stream to grow crops. Of course, just because it seems obvious doesn't mean it's feasible, and just because it's feasible doesn't mean its going to happen!
May 17, 2012 at 7:30 PM | Richard Betts
"Not at all :-) I challenge anyone to tell me that Heartland are not predominantly about propaganda!"
Richard
Challenge accepted!
I hold no brief for Heartland (especially after the maladroit Unabomber poster) but I think it would be much more accurate to say they are predominantly about counter-propaganda.
It ill behoves you to criticise Heartland for 'propaganda' when I have yet to see you admit that what the IPPC is about is primarily and specifically activist propaganda.
If you doubt this, just check out the Summary for Policy Makers. Or virtually any statement by Pachauri.
I could continue........
or even some publications from the Met Office ...
CO2 crop physiology-
How much publicity has this received?
I had to discover the CO2 crop enhancement for myself on blogs like CO2 Science.
Take a straw poll at any family/friend gathering if any of them are aware of it. Mainstream climate science appears not only to downplay, ignore or negate it by some innocent oversight, but the inevitable conclusion is that for public consumption their PR (propaganda) actively suppresses it as off-message.
Heartland is redressing a genuine mischief here.
@Richard first you say without caveat:
"It is well established that the direct physiological effects of CO2 on plants may well offset the impacts of warmer or drier conditions to some extent, but the CO2 Science website seems to focus on studies of plants subject to elevated CO2 inside chambers which are either totally enclosed or enclosed around the sides but open at the top. This makes conditions a bit artificial."
Then when I point out the known drawbacks of FACE, you say:
"Thanks, yes, I realise that FACE is still not a magic solution."
Would you have volunteered this information without "prodding"?
I find it somewhat ironic that you made these comments, especially since the subject of this particular blog is not providing the full information (a la Stern).
Also after due consideration, I have decided not to "nominate" myself to be an AR5 reviewer.
Having read how Steve McIntyre's well-researched comments were summarily dismissed
I think it would be a waste of my time.
Richard Betts, you said:
"but the CO2 Science website seems to focus on studies of plants subject to elevated CO2 inside chambers..."
Co2science.org were (still are?) very keen on reporting the FACE experiments, look through their indexed pages under 'F':
http://www.co2science.org/subject/f/subject_f.php
For most of the FACE topic subsections they have written a summary article - entitled 'summary' -I mention this because it is quite easy to overlook.
The link I gave at 3.59 (for MP's consumption) highlights the metoffice summary thus:-
'The Met Office stresses the difference between a world average temperature increase of 2degC and an increase of 4degC:
The differences between the impacts of a global mean temperature rise of 2 °C and 4 °C are stark. A rise of 4 ºC could result in a decrease in yields of all major cereal crops across most major regions of production. However, by limiting temperature rises to 2 ºC the production of some cereal crops could actually increase at mid-to-high latitudes, with negative impacts limited to regions where farming is already under threat, especially in semi-arid and tropical regions.'
Pure advocacy. Science in the service of politics.
The report does, true, include crop enhancement for wheat etc, but overwhelms it by a biblical catalogue of thunder and lightning, floods, droughts, plagues, pestilences and eternal damnation by 2050 unless we repent...
May 17, 2012 at 6:19 PM | Bad Andrew
I hope your politics aren't affecting your science. ;)
May 17, 2012 at 7:30 PM | Richard Betts
Not at all :-) I challenge anyone to tell me that Heartland are not predominantly about propaganda!
---------------------------
.... and the propaganda from WWF, Oxfam, etc., is not ? Big Green is excessively propagandist ! Why should any 'climate science' supported and promoted by BIG GREEN be treated any differently to the socialist vitriol delivered up to any literature accused of support by BIG OIL (FOSSIL FUEL) ?
"the propaganda from WWF, Oxfam, etc"
Well, the question obviously then becomes, from where does the propaganda originate? And by that I mean, is the propaganda an after-market product, or does it come from the factory?
Andrew
Martin B, Pharos, yes, exactly. If Heartland is propaganda then so is the IPCC and some of the climate hype on the Met Office website ("since the early 1900s, our climate has changed rapidly due to persistent man-made changes in the composition of the atmosphere or in land use.")
Mr Betts, the Team call their own work 'the cause ' is that propaganda or science?
You right in that Heartland is out to push a view , but they they don't claim otherwise and they certainly don't claim to be doing science let alone claim to be producing the 'best science' when in fact their efforts seem to be about propaganda. Meanwhile the IPCC is very much about 'propaganda' first with facts coming a poor second .
So although its fair comment , once again its certainly a fair comment that could be made for a number of people and organizations fully supportive of AGW.
May 17, 2012 at 8:09 PM | Martin Brumby
In my view, Heartland deserves the 'propaganda' tag more than IPCC because of Heartland's emphasis of style over substance.
IPCC reports pack a lot of information into the text, and very clearly set out quantitative information with many figures and tables, and systematically compare the results of different studies. Statements made in the summary documents are very clearly traceable back to clearly-identified sections of text with more in-depth discussion in the main volumes, where the underlying literature is cited, so that any assertion in the IPCC Summery for Policymakers can be followed back to the underpinning evidence.
In contrast, although Heartland's "NIPCC" reports are clearly designed to look superficially similar to IPCC volumes, a large part of this similarity arises simply from the thickness of the book. If you read it, the actual information content for a given length of text is much less than in IPCC - the writing style is very long-winded, and says "The three researchers did X...." and "The team of scientists found Y...." . Much of the wordage is unnecessary and merely serves to increase the length of the text without actually providing more information or making it east to read.
Moreover, it is almost all text with very few figures or tables, so there is no clear presentation of the strength of evidence, and the conclusions that are drawn tend to be qualitative not quantitative.
The most frustrating thing is that important high-level assertions in the NIPCC Summary are not easily traceable back to the arguments and evidence in the main chapters, so it is very difficult indeed to see whether the assertions made in the Summary are actually supported by a significant body of evidence. As it turns out, they are often not! (I know because I've put the effort in to find out!)