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zeupater

Leeds_Solar wrote: »

My position has remained consistent throughout.

1 - You were and remain wrong to state that there was a scientific consensus around "the earth was cooling and we were on the cusp of entering into another 'ice age'."

2 - The science you were taught re millankovitch cycles and ice ages was probably largely correct, as would have been a discussion about the slight cooling trend since the late 40s.

3 - If your teachers then attempted to conflate the 2 points, and thought this was an indication that we might be on the cusp of a new ice age, then at this point they were at odds with the majority of the published science at the time, and now. Although there were a few minority scientific opinions at the time that did think this was a possibility, these were rapidly refuted - popular science in the media however took quite a long time to catch up with the actual mainstream scientific position.

There is barely one iota of difference between any of my posts on this point.

Hi

Sorry, but that doesn't represent the way your particular position has changed over the last few days. Whether the position against my post has involved memory, bad teachers, wrong, or whatever you've thrown at the debate, my position hasn't changed .... why ?, because you've consistently been blind to the original point made .... "consensus, based on the research-based evidence available at the time" in no way limits the scope to "within the scientific community", neither does it confine the period for any relevant research to a period starting in the mid '60s and running through the '70s as per the scope of the 'myth' research which has been referenced .... you seem to have accepted this for a while, but maybe it's just a case of jumping in with both feet in order to 'toe the IPCC line of consensus' ...<humour> are there really IPCC party whips ?? </humour> ... only to discover that the position, and moreover, the history of the position, needs a little re-writing .... vested interest?, yes that would certainly encompass self esteem and a little public face ...

Furthermore, continually referencing 'your teachers' would suggest that you have completely discounted the issue of different teachers delivering the same message in different schools (for the record, in different years too) would actually suggest that commonality would exist through the syllabus being taught and the textbooks available at the time. I have to really question why ... could it be that individual 'teachers' are easy targets, mostly deceased, and are not classified as being true members of the 'academia club' whilst taking the purely scientific & logical approach of researching what the contemporaneous views of the examination boards linked to some of the worlds foremost centres of academia actually were could raise the possibility of academic discord with other disciplines and/or centres of excellence .... I fully understand that a syllabus can remain unchanged for years & therefore may not track the latest 'scientific' thinking, or even consensus, but that in no way means (or has ever meant) that latest research changes past consensus ... this is a major flaw in the argument which I'm extremely surprised still hasn't been recognised .... (or maybe it has, but just not communicated ! ... )

HTH
Z

zeupater

Leeds_Solar wrote: »

If you entirely miss out the scale of any change, and neglect to point out the preceding warming period, and unusual high temperatures of the preceding decade (40s) you'd almost have a point.


There was actually only 1 decade of actual cooling, following a peak in the 40s, both the 60's and 70's were still slightly cooler than the 40s, but warmer than the 50s. Depending on your start and end points you can make the case for there having been 30 years of marginal cooling, but essentially there was a minor correction in the 50s following an exceptionally hot 40s, followed by a 20 year period of stagnation, which then gave way to rapid decade on decade rises from the end of the 70's onwards.

Or to put it another way,

In the last 50 years all 5 decades have been warmer than the previous decade

In the last 100 years 9 decades were warmer than the preceding decade, and just 1 decade was slightly cooler than the preceding decade.

Hi

The issue is that decades have fixed start & end dates, much better to present the data as a rolling average ... that way you'd see a more realistic trend ... this is how all of this discussion started ...

Have a look at the HadCET 1659 dataset, drop it into a spread-sheet then average the previous 5/10/20/30/50 years for each year into separate columns .... calculate the differences between each dataset (including the year specific) and the next highest period, set the negatives to show red then graph the resultants ... you will effectively have both an offset trend dataset & offset chart, but look what it's telling you .... possibly where short termism and a longer term view overlap ? ... relative periods of warming & cooling ? ...

There you go, a simple exercise with interesting results ... I did it years ago ...

Interestingly, if you actually analyse the monthly HadCET data you'd also find that the correlation between monthly, or seasonal, warming may not be exactly what you would expect if you've only ever considered to look at annual data or associated research ...

Don't you just love data & logic .... it's goes a long way towards separating at least a proportion of humankind from the 'selfish herd' ...

HTH
Z

Leeds_Solar

zeupater wrote: »

why ?, because you've consistently been blind to the original point made .... "consensus, based on the research-based evidence available at the time" in no way limits the scope to "within the scientific community", neither does it confine the period for any relevant research to a period starting in the mid '60s and running through the '70s as per the scope of the 'myth' research which has been referenced ....

So let's be clear than, when you were talking about a consensus existing in the 70's you specifically didn't actually mean a consensus scientific position, you actually meant some form of consensus in popular science understanding as apparently exemplified by some high school teachers?

And when you stated it was based on the research based evidence available at the time, you actually didn't mean that either, as the research based evidence available at the time mostly supported the warming hypothesis.

So basically nothing at all like the actual scientific consensus that exists now, and you were therefore wrong to compare the two?

but that in no way means (or has ever meant) that latest research changes past consensus ... this is a major flaw in the argument

It certainly remains a major flaw in your argument if you're really attempting to state that research papers conducted and published throughout the 70's should not be seen as having any bearing on what may or may not be viewed as being the consensus scientific position in the 70s.

ps I don't know if you're bored of this yet, I certainly am. There definitely was no scientific consensus around imminent cooling in the 70s, but I'll accept there's a possibility that those setting 1 or more of the high school exam curriculum at the time might not have updated their curriculum to more accurately reflect the thinking at the time.

Please note that I am not, and never have claimed that there was a scientific consensus in favor of warming at the time either - a fair reflection of the situation would have been that there was no consensus on either warming or cooling, other than that the climate was much less stable, and more vulnerable to change due to relatively small levels of forcings than had previously been thought.

My interpretation of the situation was that there were a few papers that got the calculations wrong that predicted imminent long term cooling either from air pollution, sun spots or millankovitch cycles, which received high profile media coverage due to their alarmist nature. Each of these papers was rapidly refuted in the scientific literature, but this didn't receive anything like the same level of media profile, so the popular perception remained at odds with the actual scientific position of the time.

Leeds_Solar

zeupater wrote: »

Hi

The issue is that decades have fixed start & end dates, much better to present the data as a rolling average ... that way you'd see a more realistic trend ... this is how all of this discussion started ...

Have a look at the HadCET 1659 dataset, drop it into a spread-sheet then average the previous 5/10/20/30/50 years for each year into separate columns .... calculate the differences between each dataset (including the year specific) and the next highest period, set the negatives to show red then graph the resultants ... you will effectively have both an offset trend dataset & offset chart, but look what it's telling you .... possibly where short termism and a longer term view overlap ? ... relative periods of warming & cooling ? ...

There you go, a simple exercise with interesting results ... I did it years ago ...

Interestingly, if you actually analyse the monthly HadCET data you'd also find that the correlation between monthly, or seasonal, warming may not be exactly what you would expect if you've only ever considered to look at annual data or associated research ...

Don't you just love data & logic .... it's goes a long way towards separating at least a proportion of humankind from the 'selfish herd' ...

HTH
Z

But using an 'offset trend dataset' is just a technical sounding way of saying that you've falsely moved the averaging point from the centre of the data series to one end of it.

The only reason to do that in this case would be either that you don't know what you're doing, or that you're deliberately seeking to mislead.

I'm not sure which applies here.


The accepted way of doing what you're trying for is to use a rolling mean, so for a 5 year rolling average it would take the data from that year and 2 years either side of it and average that data.

What you're doing is effectively falsely moving that centre point to the end of the data series so that on the 50 year average graph the data you're displaying for 2010 should actually be being viewed as the data for 1985.

and yes, I have put that data into excel before now and produced various rolling mean graphs from it, I just did it properly and therefore didn't end up misleading myself or others about what the data was saying.

Leeds_Solar

oh hang on, you're talking about hadcet?

as in the central england temperature record?

erm ok, no I've not carried out that analysis for that specific data, not really sure why you would though or what you'd expect a dataset for one single location to prove about global climate changes.

zeupater

Leeds_Solar wrote: »

So let's be clear than, when you were talking about a consensus existing in the 70's you specifically didn't actually mean a consensus scientific position, you actually meant some form of consensus in popular science understanding as apparently exemplified by some high school teachers?

And when you stated it was based on the research based evidence available at the time, you actually didn't mean that either, as the research based evidence available at the time mostly supported the warming hypothesis.

So basically nothing at all like the actual scientific consensus that exists now, and you were therefore wrong to compare the two?



It certainly remains a major flaw in your argument if you're really attempting to state that research papers conducted and published throughout the 70's should not be seen as having any bearing on what may or may not be viewed as being the consensus scientific position in the 70s.

ps I don't know if you're bored of this yet, I certainly am. There definitely was no scientific consensus around imminent cooling in the 70s, but I'll accept there's a possibility that those setting 1 or more of the high school exam curriculum at the time might not have updated their curriculum to more accurately reflect the thinking at the time.

Please note that I am not, and never have claimed that there was a scientific consensus in favor of warming at the time either - a fair reflection of the situation would have been that there was no consensus on either warming or cooling, other than that the climate was much less stable, and more vulnerable to change due to relatively small levels of forcings than had previously been thought.

My interpretation of the situation was that there were a few papers that got the calculations wrong that predicted imminent long term cooling either from air pollution, sun spots or millankovitch cycles, which received high profile media coverage due to their alarmist nature. Each of these papers was rapidly refuted in the scientific literature, but this didn't receive anything like the same level of media profile, so the popular perception remained at odds with the actual scientific position of the time.

Hi

What needs to be realised is that whatever bias hindsight and historical interpretation can throw on the subject, if any research which wasn't mainstream enough to be considered when the syllabus was set, then it's irrelevant, so is all research conducted in the '70s which was published and became mainstream after the examination process .... however, this is exactly what the 'Myth' paper misses .... furthermore, the 'Myth' paper attempts to gain credibility by counting and comparing how many times the referenced papers were cited up to 1983, but looking at one of the most cited supporting 'warming', "Manabe and Weatherald (1967)", of the '306' stated, the count was 8 prior to 1970, 86 prior to 1975 & still only 206 before the '70s actually ended .... hardly relevant if a GCE syllabus was set/reviewed on a ~4year basis (1969,73,76 ?) at that time ...

I really do agree with your position on the level of true 'scientific consensus' at the time as there was no formal forum for open discussion from which significant consensus could be derived .... but then again, it could be argued that there still isn't

HTH
Z

zeupater

Leeds_Solar wrote: »

But using an 'offset trend dataset' is just a technical sounding way of saying that you've falsely moved the averaging point from the centre of the data series to one end of it.

The only reason to do that in this case would be either that you don't know what you're doing, or that you're deliberately seeking to mislead.

I'm not sure which applies here.


The accepted way of doing what you're trying for is to use a rolling mean, so for a 5 year rolling average it would take the data from that year and 2 years either side of it and average that data.

What you're doing is effectively falsely moving that centre point to the end of the data series so that on the 50 year average graph the data you're displaying for 2010 should actually be being viewed as the data for 1985.

and yes, I have put that data into excel before now and produced various rolling mean graphs from it, I just did it properly and therefore didn't end up misleading myself or others about what the data was saying.

Hi

I know what I'm doing, how else would you compare a 50 year data set with a 30,20,10,5 and annual and still make it relevant to 2013 ? ... move the offset if you want, but then it wouldn't be a historical trend ....

Just try it .... and yes, HadCET is a good place to start thinking ... 350 years should be enough to see how it works ....

HTH
Z

Leeds_Solar

zeupater wrote: »

Hi

What needs to be realised is that whatever bias hindsight and historical interpretation can throw on the subject, if any research which wasn't mainstream enough to be considered when the syllabus was set, then it's irrelevant, so is all research conducted in the '70s which was published and became mainstream after the examination process .... however, this is exactly what the 'Myth' paper misses .... furthermore, the 'Myth' paper attempts to gain credibility by counting and comparing how many times the referenced papers were cited up to 1983, but looking at one of the most cited supporting 'warming', "Manabe and Weatherald (1967)", of the '306' stated, the count was 8 prior to 1970, 86 prior to 1975 & still only 206 before the '70s actually ended .... hardly relevant if a GCE syllabus was set/reviewed on a ~4year basis (1969,73,76 ?) at that time ...

I really do agree with your position on the level of true 'scientific consensus' at the time as there was no formal forum for open discussion from which significant consensus could be derived .... but then again, it could be argued that there still isn't

HTH
Z

The IPCC might have missed a trick here, as I'm not sure they canvassed the opinions of the UK's high school teachers prior to releasing their latest consensus report.

What you're basically doing is asserting that the tail should be viewed as wagging the dog.

And that's not really why there was no scientific consensus, it was purely that the study of the subject itself was in its relative infancy, the data sets were only just starting to be collated, the computing power wasn't there to do complex modelling etc.

That doesn't now apply.

Consensus in science emerges through the scientific literature, via published peer reviewed papers, which others can then attempt to replicate, test and if possible refute (as well as conferences etc). So it's a completely valid method to assess the level of consensus by retrospectively assessing the content of the scientific papers being published at the time in question.

Leeds_Solar

zeupater wrote: »

Hi

I know what I'm doing, how else would you compare a 50 year data set with a 30,20,10,5 and annual and still make it relevant to 2013 ? ... move the offset if you want, but then it wouldn't be a historical trend ....

If you really do know what you're doing, then you would be deliberately misleading people, but I suspect you've really accidentally misled yourself.

You wouldn't use wide rolling means for a short dataset, they wouldn't be appropriate, you need long datasets to make wide running means a useful tool to be used.

You can't get a 50 year rolling mean for 2013, that data set would currently end in 1988, all you've done is to move the 1988 figure to 2013 and pretend that it's in any way relevant to 2013 (excluding the Dr Who potential t obtain data from the next 25 years).

zeupater wrote: »

Just try it .... and yes, HadCET is a good place to start thinking ... 350 years should be enough to see how it works ....

the dataset is fine, but it tells you very little about the actual global situation - no single data point could, so it's a bit wrong to start referencing it when discussing global temperature trends.

It's why the error bands get so much bigger as the longer term temperature datasets go back further in time to the point where there's only a few datasets, or even back to the point where the CET is the only direct datapoint, and proxies have to be used for the temperatures elsewhere.

zeupater

Leeds_Solar wrote: »

The IPCC might have missed a trick here, as I'm not sure they canvassed the opinions of the UK's high school teachers prior to releasing their latest consensus report.

What you're basically doing is asserting that the tail should be viewed as wagging the dog.

And that's not really why there was no scientific consensus, it was purely that the study of the subject itself was in its relative infancy, the data sets were only just starting to be collated, the computing power wasn't there to do complex modelling etc.

That doesn't now apply.

Consensus in science emerges through the scientific literature, via published peer reviewed papers, which others can then attempt to replicate, test and if possible refute (as well as conferences etc). So it's a completely valid method to assess the level of consensus by retrospectively assessing the content of the scientific papers being published at the time in question.

Hi

We both know what was meant, and yet again, simply checking the reasoning/criteria for inclusion the syllabus would be much better than a simple count ... Looking at the syllabus review history it seemed to be 4 years (1969,73,76), so anything not considered mainstream before 1976 wouldn't even be within a syllabus being taught in the 1970s ...

I'm afraid that history is best written on a contemporaneous basis .... reviewing history through archaeological consensus could possibly provide further insight, but rarely trumps the written account detail .... does it usually cause historical accounts to be re-written, or just seen in a different light ?

Keep it simple and ask the questions which should be asked, not the ones which provide convenient answers ....

HTH
Z