How will global warming play out?

[intention]

@jshore

Look, intention, I agree with you that if you do the same exact mathematical operations on a set of data then, to the limits of machine precision, you will get the same result and this will be the sort of exact mathematical replication that you are speaking of.

However, and this is the important point which is why I am bolding it: In the physical sciences when it is talked about researchers having to give enough detail for others to replicate their results, this is not the standard that is generally demanded. I know of absolutely no journal in the physical sciences that requires authors to give enough details of their work to allow this standard of replication. It may be that you feel that this should be the standard. Then, by all means, it is your perogative to try to fight for a major sea-change in the way that research in the physical sciences is done. However, to demand that Mann et al. live up to a standard that is not in fact the standard that is expected of him by the journals he publishes in or by his peers in the field is simply not realistic.

Look, I gave you an example of Monte Carlo simulation but in fact I could give you an example with no random numbers involved: The code that I use at work has a step where we take experimental data and interpolate it for further use in the modeling. The interpolation routine is complicated…in fact, iterative. To allow people to replicate my calculations to the degree that you are demanding would require me practically publishing the interpolation routine code line-for-line. This is so far from anything that any journal in the field would ever demand from me as to be frankly amusing to contemplate!

Now, in my own work with my own computer codes, I do sometimes like to make sure that a change I make to the code is still resulting in the same results down to this level of accuracy. Other times, I have made changes to the code that I know may actually cause changes in the results that are not physically significant but do not constitute exact replication in this strict mathematical sense. For my own edification, when I am recording modifications to my code, I try to make a special note to myself when I do make a change that I think can make small mathematical changes in the results. However, as I will repeat again for emphasis, when scientists talk about other scientists having to give enough details to allow replication of results, they are not talking about it having to be done to the level of detail necessary for this to be true in a strict mathematical sense. The sense of replication that is meant is the sense of getting the same basic physical result. This is clearly true in experimental work where it would be impossible to have a higher standard. However, even in numerical work such as Mann’s where it is t least in theory possible to demand this higher standard for replication, that is not the standard that is demanded.

jshore, thank you for your thoughtful comments. Mann does not have any iterative routines such as you describe. He doesn’t have any Monte Carlo analysis. He has a mathematical operation which was incorrectly described in the text. This error could not be found without the code, and meant that his work could not be replicated.

Yes, if there is Monte Carlo, if there are iterative routines such as you describe, the final results may differ slightly. But this is a situation where A + B doesn’t equal C.

I truly don’t understand why you would want to defend someone who hid his data and code and misrepresented his procedures and results so badly that he had to issue a corrigendum to his work to (partially) fix his mistakes.

I also don’t understand your defense of the peer-review system. If it worked as well as you seem to think it works … why was it necessary for Mann to issue a corrigendum to Nature to fix his errors? He hadn’t even correctly listed his sites. He extended data back in time to allow it to be used to “prove” his point. This was all revealed in the Corrigendum. Why weren’t these errors caught in the peer-review?

You are defending a man who falsified data. Made it up out of thin air to support his contentions. You are welcome to do so … me, I prefer science.

w.

[intention]

To review the bidding, jshore, you had said:

@jshore

When Browne stood up at Stanford this past spring, he was there to report hard numbers: BP had not just met its target – to reduce its emissions of greenhouse gases by 10 percent below 1990 levels – it had exceeded it, done so eight years ahead of schedule and with no net economic cost. In fact, because of energy efficiency measures, the emissions reductions amounted to a net gain of $600 million. ‘‘And we are not,’’ he told me later, ‘‘an inefficient company.’’

I replied:

@intention

And we know this how? jshore, have you suddenly started trusting the unsupported statements of oil company executives? Gotta confess, that surprises me … did he open up the books so his statement could be verified? Did he detail how they claim to have done it?

You said:

@jshore

This post of yours goes back a ways and I had meant to respond to it earlier: In fact, BP has been releasing lots of information http://www.bp.com/sectiongenericarticle.do?categoryId=4535&contentId=7016526 about their sustainability practices…and has had these statements auditted by Ernst & Young.

Well, I looked at that. It doesn’t support his claim. It says:

Our Own Operations

Greenhouse gas emissions from our operations in 2004 were equivalent to 81.7 million tonnes CO2. Since 2001 approximately half of our total underlying emissions growth (around 7 million tonnes) has been offset by sustainable efficiency projects. Significant emission reductions achieved in 2004 were:

400,000 tonnes from reduced flaring and venting of gas in Canada, Abu Dhabi and Trinidad

250,000 tonnes from energy efficiency measures in the USA at the Whiting refinery and Texas City

100,000 tonnes from energy efficiency measures taken across the petrochemicals business

beginning in 2004, each year approximately 1 million tonnes of CO2 will be compressed and injected into wells 1,800 metres below the In Salah gas reservoir in the Algeria desert. This reduces GHGs by the equivalent of taking 200,000 cars off the road

Note that, far from supporting his claim that they have reduced emissions to below 1990 levels, the report actually says that their emissions are still increasing by 7 million tonnes per year. Like my father used to say, “The big print giveth … and the small print taketh away …”

w.

[jshore]

@intention

Note that, far from supporting his claim that they have reduced emissions to below 1990 levels, the report actually says that their emissions are still increasing by 7 million tonnes per year. Like my father used to say, “The big print giveth … and the small print taketh away …”

First of all, the 7 million tonne increase is not per year but is the total between 2001 and 2004 and half of it was offset by “sustainable efficiency projects”.

Second, the numbers that you quote there do not address the original claim made by Browne which was that by 2001, the company had exceeded its goal of reducing emissions 10% below 1990 levels. Since then, it seems that emissions have claimed back up somewhat…but they remain well below 1990 levels. For someone who was such a stickler for detail when we were talking about trend lines over slightly different time periods in regards to the UAH temperature analysis, you seem quite cavalier in this regard here where the time periods don’t even overlap!

[My point in linking to these pages was to show you the way in which they are publicly releasing their emissions information and having it verified by Ernst and Young.]

[Jackmannii]

How will global warming play out?

Having seen a rerun of the 1958 classic *The Blob* on TCM last night, I know what will happen: The Arctic will warm past the danger point, and The Blob (which was dropped there by an Air Force transport plane) will defrost and roll south, engulfing everything in its path.

It’s only a matter of time. :eek:

[jshore]

By the way, I haven’t succeeded in finding a direct comparison of BP greenhouse gas emissions now to those in 1990; however, here is a PDF file that has figures for 1999-2005. You can see that their emissions in 2005 are back below what they were in 2001…and about 15% below what they were in 1999.

[jshore]

@intention

jshore, thank you for your thoughtful comments. Mann does not have any iterative routines such as you describe. He doesn’t have any Monte Carlo analysis. He has a mathematical operation which was incorrectly described in the text. This error could not be found without the code, and meant that his work could not be replicated.

I think you are missing the forest through the trees in regards to what I am saying, which is that regardless of whether the code has iterative routines or Monte Carlo routines or not: In the physical sciences when it is talked about researchers having to give enough detail for others to replicate their results, your standard (of being able to replicate the results exactly in a strict mathematical sense essentially to machine precision) is not the standard that is generally demanded. If it were demanded, then scientists would have to describe their calculations in way more detail than they do in standard practice. Whether this is a good or bad thing is something that one can debate…However, one should not deny the reality of how things actually currently work.

[intention]

@jshore

I think you are missing the forest through the trees in regards to what I am saying, which is that regardless of whether the code has iterative routines or Monte Carlo routines or not: In the physical sciences when it is talked about researchers having to give enough detail for others to replicate their results, your standard (of being able to replicate the results exactly in a strict mathematical sense essentially to machine precision) is not the standard that is generally demanded. If it were demanded, then scientists would have to describe their calculations in way more detail than they do in standard practice. Whether this is a good or bad thing is something that one can debate…However, one should not deny the reality of how things actually currently work.

The reality of how things actually currently work was that several groups of people tried to replicate Mann’s work and failed. After that, he was forced to issue a Corrigendum. With that information, Wahl and Amman came close to replicating it, but still did not reproduce the following points (from CA )

1. the selection of proxies which was supposedly done according to “clear a priori” criteria. The “clear a priori” criteria were not reported and have not been disclosed in response to inquiries. Without a statement of these “clear a priori” criteria, it is obviously impossible to replicate the proxy selections of MBH98.

2. the selection of tree ring chronologies listed in the original SI according to the criteria listed in Mann et al [2000] (which expanded on MBH98 information); here

3. the explanation in the Corrigendum for the discrepancy between the tree ring sites listed as being used in the original SI and the tree ring sites actually used. The exclusion of the excluded sites (and the inclusion of included sites) cannot be replicated according to the stated criteria. here

4. the data set archived in July 2004 does not match the description provided in MBH98 or in the Corrigendum SI. here

5. the proxy rosters in each calculation step from pre-Corrigendum information, including a total of 159 series said to have been used in MBH98 [Mann et al , 2003]here

6. the use of 24 proxy series in the AD1450 step as reported in MBH98 here

7. failure to use 6 available proxy series in the AD1500 step (including 5 series used in the AD1450 step) here

8. the selection of the 1082 “dense” gridcells and 219 “sparse” gridcells according to the selection criteria stated (for the first time) in the Corrigendum SI. here

9. the archived “sparse” and “dense” instrumental series here

10. the number of retained temperature PC series in each calculation step. The number retained appears to depend on short-segment standardization, which we criticized in connection with tree ring series. The number retained cannot be replicated with non-erroneous PC methods.

11. the number of tree ring PC series retained in each network/calculation step according to the retention policy (Preisendorfer’s Rule N) reported at realclimate.org [link] in December 2004. No information was provided in MBH98, the Corrigendum talked about a scree test being used as well. I can replicate the illustration at realclimate for the AD1400 North American network, but as soon as you try other networks/periods, the criterion can’t be replicated. here

12. the Corrigendum states that PC series were re-calculated for each calculation step, but this is not correct. The actual selection of steps in which fresh calculations are made is impossible to replicate.

13. is there an unreported step commencing in 1650? If you plot the confidence intervals, there is a step here, but there is no mention anywhere of a step commencing in 1650 in MBH98 or the new SI. An archived reconstructed PC also begins in 1650: what’s going on here? here

14. the 5 archived RPCs cannot be replicated. Here I wish to emphasize that my emulations of the RPCs were identical to those of Wahl and Ammann. However, they are content if their emulation is roughly similar to MBH98; I am not. here

15. why does the RPC replication deteriorate in the early 15th century. The 15th century is obviously a problem area. Given other issues with the 15th century, I’m really interested to see what’s going on here. here

16. the reconstructed NH temperature series from the RPCs here

17. In MM03, we reported collation problems in the data set archived at Mann’s FTP site to which we were originally given access. After publication of MM03, Mann made the duplicate accounts available and a new FTP site appeared. Mann said that the collation errors in the previous accounts did not exist in the actual accounts. However, Rutherford referred to a file pcproxy (retrieved from the Wayback machine) long before our inquiry. I think that it’s quite possible that the collation errors in the first data set did not exist in the actual data set (and not much turns on this in terms of the final results), but, for good order’s sake, I’d like to see code demonstrating that collation errors were not made. I have a sneaking suspicion that they were made and that this is one of the reasons why Mann is so reluctant to show his code.

18. MBH98 and Mann et al [2000] both stated that MBH results were “robust” to presence/absence of all dendroclimatic indicators. A fortiori, this entails that MBH98 results are “robust” to the presence/absence of the bristlecones (and the PC4). Wahl and Ammann do not report that they have replicated this result – I wonder why not?

19. MBH98 stated that they had done R2 cross-validation tests and Mann told Natuurwetenschap that his reconstruction passed an R2 cross-validation test. Again we can surmise the answer – I presume that Wahl and Ammann have replicated the catastrophic failure of the R2 test and have similarly replicated MBH withholding of this information. This is not really the type of replication that one wants.

20. confidence interval calculations in MBH98 here and here

21. data citations for instrumental series. These are currently attributed only to NOAA, which is not an adequate citation.

Now, you may think this is perfectly adequate replication. I find such things as the failure of Wahl and Amman to report the R2 statistic (which the paper and the replication both failed) to be a clear indication that their paper is a whitewash. You may accept whitewash jobs in your field of science. I don’t.

If don’t you want to discuss the issues and just claim the “All is for the best in this best of all possible worlds” like Candide , fine. If you want to tell me you are happy with with a “replication” without any discussion of not following a priori rules for proxy selection, mysterious and unexplained jumps in confidence intervals, incorrect descriptions of the timing of recalculations, discrepancies between the archived data and the data used, problems with the number of series retained in each step, unexplained collation changes, and false claims of “robustness”, that’s fine too.

Just don’t describe that as science. It’s not. The whole reconstruction depends entirely on the inclusion of a few bristlecone pine proxies, which are known, and noted several places in the literature, to have big problems. These problems are so bad that the NAS report said that they shouldn’t be used in temperature reconstructions at all.

Without the bristlecones, the Mann method shows the Medieval Warm Period as being warmer than the present … so you can see why they are fighting so hard for this piece of garbage. It is not robust, you get a very different result by taking out a few proxies. Notably, but not surprisingly, Wahl and Amman didn’t comment on that at all. Perhaps you’d care to comment on a “replication” that doesn’t mention the elephant in the room? …

w.

[intention]

jshore, now you have me confused. First you say:

@jshore

… the 7 million tonne increase is not per year but is the total between 2001 and 2004 and half of it was offset by “sustainable efficiency projects”.

Then you say:

@jshore

… their emissions in 2005 are back below what they were in 2001…and about 15% below what they were in 1999.

The citation you gave, however, shows 2001 emissions at 80.5 Mtonnes and 2004 emissions of 81.7 Mtonnes, a 1.2 million tonne increase. So something’s not right, they’re massaging the numbers.

Like I said, you can trust the oil companies to play fast and loose with the numbers …

Finally, you seem to think that the fact the report was audited by Ernst and Young means something. Every audit report has a disclaimer at the bottom saying what they are taking responsibility for. In this case, it says:

BP’s environmental and social web content 2005 (the Report) has been prepared by the management of BP p.l.c., who are responsible for the collection and presentation of information within it. Our responsibility, in accordance with BP management’s instructions, is to carry out a limited assurance engagement on the Report, in order to provide conclusions in relation to Materiality, Completeness and Responsiveness.

Our responsibility in performing our assurance activities is to the management of BP p.l.c. only and in accordance with the terms of reference agreed with them. We do not therefore accept or assume any responsibility for any other purpose or to any other person or organization. Any reliance any such third party may place on the Report is entirely at its own risk.

In other words, they only made sure that the addition is correct. They got the numbers from BP, and they have not checked the numbers, they’re from BP. I’m surprised, as I said before, that you take BP’s word for anything … even Ernst & Young say you are taking BP’s word “at your own risk” …

w.