5 ms·

You ask good questions, and raise good points. Since one can't read all the primary sources, how can you decide who to trust? In this case, I don't think the

by nkurz 8y ago

You ask good questions, and raise good points. Since one can't read all the primary sources, how can you decide who to trust? In this case, I don't think there is a simple and logically defensible answer. Normally, your best bet would be to trust that the recognized experts in the field probably have it right. But I think Climate Science is so politicized at this point that unless you can sit down and have a beer at a backyard BBQ with those experts, anything you read is more likely to be well-calculated propaganda than the experts' true beliefs. The data presented in the papers is largely true, but the ancillary spin is so strong that it's hard to know what to conclude without a close reading of the entire paper. And even then, the choice of which papers are published in which journals makes it hard to know how much weight to put on what. So you ask why to trust Willis Eschenbach. For me, I trust him because I've been reading his comments on ClimateAudit.org for well over a decade, and I've never seen him attempt to mislead. He's occasionally wrong, and but readily owns up to his errors. My impression from reading him over many years is that he's a smart guy who believes what he's saying, knows a lot about the field, has no obvious conflicts of interest, and does his best to be accurate. I don't feel like the SkepticalScience.com post you linked to treats him fairly. Since that post considers him together with McIntyre, the best answer I can provide is that you should read McIntyre's latest post (https://climateaudit.org/2018/10/24/pages2k-north-american-tree-ring-proxies/ https://climateaudit.org/2018/10/24/pages2k-north-american-t...) and see if you think their criticisms actually apply. I realize this isn't anything approaching rock-solid logic, but personal testimonial is the best I can offer. As a fervent environmentalist who has been closely reading McIntyre since soon after MBH98 came out, I'm still firmly under his sway, and think his criticisms have still not been adequately addressed.

eesmith 8y ago
As best as I can tell, the politicization of climate science is a deliberate action by those opposed to the actions which will result from accepting the validity of its conclusions. It's the same sort of propaganda effort which fought against the recognition of the link between cigarettes and lung cancer. It's the same sort of effort which tries to get creationism in its varied forms taught as part of a science education in schools. The goal of which is to muddy the waters, and cause people to throw up their hands and declare a pox on both their houses. Is McIntyre going to publish his objections? Or just leave it as a blog post on a site mostly read by sympathetic readers? Since he's 'criticized [this sort of analysis] from [his] beginning in this field', surely he's published his objections, yes? Or someone else has? Why does he refer to "Climategate" twice ("In the weeks prior to Climategate" and "On this day in 2009, a few weeks before Climategate") when multiple inquiries by US and UK organizations found no evidence of fraud or scientific misconduct? Doesn't he realize that that choice of term is politicized, and the use of it likely to be used as a flag to categorize the user in the same box as creationists and tobacco lobbyists?
- eesmith 8y ago
  Followup since it was too late to edit. McIntyre's blog post starts "The PAGES (2017) North American network consists entirely of tree rings.". The 2017 article "A global multiproxy database for temperature reconstructions of the Common Era" by the PAGES2k Consortium at https://www.nature.com/articles/sdata201788 https://www.nature.com/articles/sdata201788 says: > While the M08 database contains 75% more records than this collection, these records are overwhelmingly land-based, from the Northern Hemisphere, and relatively short. Indeed, the M08 database is disproportionately composed of tree rings from North America, many of which start after 1000 CE, so that fewer than 100 records reach beyond this date. In contrast, the present collection contains 176 records out to 1000 CE, most of which are not tree-based. I assume "records" is not the same as "series", because the Supplementary Table spreadsheet mostly lists tree ring data for North America. However, it does list 12 lake sediment series and one speleothem series. For example, NAm_065 is "Late Holocene Climate Changes in Eastern North America Estimated from Pollen Data" from https://www.cambridge.org/core/journals/quaternary-research/article/late-holocene-climate-changes-in-eastern-north-america-estimated-from-pollen-data/C8C7903CA7A6687F9C63F8D12079C4D8 https://www.cambridge.org/core/journals/quaternary-research/... . How am I supposed to reconcile McIntyre's statement "entirely of tree rings" with the publication? If tree rings are to be ignored, wouldn't the right question be, what does the analysis look like using only the non-tree ring data for North America?
  - nkurz 8y ago
    How am I supposed to reconcile McIntyre's statement "entirely of tree rings" with the publication? I haven't read PAGES 2017 before, but I think the issue is that all the non-tree-ring proxies have been "screened out" from the North American network prior to data analysis. This is detailed (with helpful maps) in the Supplementary Information: https://media.nature.com/original/nature-assets/sdata/2017/sdata201788/extref/sdata201788-s2.pdf https://media.nature.com/original/nature-assets/sdata/2017/s.... As they apply successive layers of screening for factors such as "False Discovery Rate" and correlation with "Mean Annual Temperature", everything except the tree ring proxies drop out from North America (other than a single coral series in the Yucatan). This is essentially the basis of McIntyre's criticism of the paper. Traditional statistical technique says that you should come up with criteria for a valid proxy in advance, screen without looking at the data, and then use all the data. Once you start screening out sites after peeking at the data that is going to be used for your analysis, it's hard to know if you've biased your results towards a preordained conclusion. You should pause at this point and ask yourself: Is this really what the paper does? How do they justify that? What do outside statisticians think of this approach? Why isn't this talked about more prominently outside of the "skeptic" blogs? If tree rings are to be ignored, wouldn't the right question be, what does the analysis look like using only the non-tree ring data for North America? Yes, this is a fine question, although McIntyre isn't suggesting that all tree series be ignored, only a few problematic "stripbark bristlecone pines". In prior work, the answer is that if you leave out these few trees, the emblematic "hockey stick" graph disappears. It's possible to recover the sharp upward rise without the stripbarks, but only by adding in an "upside down" Finnish lake sediment proxy (upside down in the sense that the principle components analysis inverts the usual correlation of thick and thin layers to hot and cold). This is what section of the blogpost with the subtitle "Background: Stripbark Bristlecones and Mann’s CENSORED Directory" is about. The "spaghetti graphs" are showing the contributions from the other groups of proxies. Reading the historical links in that section will give you a tour of McIntyre's argument. His argument is not that global warming is not happening, just that much of the proof being offered is statistically very flawed. (It's worth noting the parallels between the criticism of post-hoc screening above, and the suggestion that the bristlecone pines should be screened out. Why one, and not the other? I don't think there's a clear answer.)

by nkurz 8y ago

eesmith 8y ago

As best as I can tell, the politicization of climate science is a deliberate action by those opposed to the actions which will result from accepting the validity of its conclusions. It's the same sort of propaganda effort which fought against the recognition of the link between cigarettes and lung cancer. It's the same sort of effort which tries to get creationism in its varied forms taught as part of a science education in schools. The goal of which is to muddy the waters, and cause people to throw up their hands and declare a pox on both their houses. Is McIntyre going to publish his objections? Or just leave it as a blog post on a site mostly read by sympathetic readers? Since he's 'criticized [this sort of analysis] from [his] beginning in this field', surely he's published his objections, yes? Or someone else has? Why does he refer to "Climategate" twice ("In the weeks prior to Climategate" and "On this day in 2009, a few weeks before Climategate") when multiple inquiries by US and UK organizations found no evidence of fraud or scientific misconduct? Doesn't he realize that that choice of term is politicized, and the use of it likely to be used as a flag to categorize the user in the same box as creationists and tobacco lobbyists?

eesmith 8y ago
Followup since it was too late to edit. McIntyre's blog post starts "The PAGES (2017) North American network consists entirely of tree rings.". The 2017 article "A global multiproxy database for temperature reconstructions of the Common Era" by the PAGES2k Consortium at https://www.nature.com/articles/sdata201788 https://www.nature.com/articles/sdata201788 says: > While the M08 database contains 75% more records than this collection, these records are overwhelmingly land-based, from the Northern Hemisphere, and relatively short. Indeed, the M08 database is disproportionately composed of tree rings from North America, many of which start after 1000 CE, so that fewer than 100 records reach beyond this date. In contrast, the present collection contains 176 records out to 1000 CE, most of which are not tree-based. I assume "records" is not the same as "series", because the Supplementary Table spreadsheet mostly lists tree ring data for North America. However, it does list 12 lake sediment series and one speleothem series. For example, NAm_065 is "Late Holocene Climate Changes in Eastern North America Estimated from Pollen Data" from https://www.cambridge.org/core/journals/quaternary-research/article/late-holocene-climate-changes-in-eastern-north-america-estimated-from-pollen-data/C8C7903CA7A6687F9C63F8D12079C4D8 https://www.cambridge.org/core/journals/quaternary-research/... . How am I supposed to reconcile McIntyre's statement "entirely of tree rings" with the publication? If tree rings are to be ignored, wouldn't the right question be, what does the analysis look like using only the non-tree ring data for North America?
- nkurz 8y ago
  How am I supposed to reconcile McIntyre's statement "entirely of tree rings" with the publication? I haven't read PAGES 2017 before, but I think the issue is that all the non-tree-ring proxies have been "screened out" from the North American network prior to data analysis. This is detailed (with helpful maps) in the Supplementary Information: https://media.nature.com/original/nature-assets/sdata/2017/sdata201788/extref/sdata201788-s2.pdf https://media.nature.com/original/nature-assets/sdata/2017/s.... As they apply successive layers of screening for factors such as "False Discovery Rate" and correlation with "Mean Annual Temperature", everything except the tree ring proxies drop out from North America (other than a single coral series in the Yucatan). This is essentially the basis of McIntyre's criticism of the paper. Traditional statistical technique says that you should come up with criteria for a valid proxy in advance, screen without looking at the data, and then use all the data. Once you start screening out sites after peeking at the data that is going to be used for your analysis, it's hard to know if you've biased your results towards a preordained conclusion. You should pause at this point and ask yourself: Is this really what the paper does? How do they justify that? What do outside statisticians think of this approach? Why isn't this talked about more prominently outside of the "skeptic" blogs? If tree rings are to be ignored, wouldn't the right question be, what does the analysis look like using only the non-tree ring data for North America? Yes, this is a fine question, although McIntyre isn't suggesting that all tree series be ignored, only a few problematic "stripbark bristlecone pines". In prior work, the answer is that if you leave out these few trees, the emblematic "hockey stick" graph disappears. It's possible to recover the sharp upward rise without the stripbarks, but only by adding in an "upside down" Finnish lake sediment proxy (upside down in the sense that the principle components analysis inverts the usual correlation of thick and thin layers to hot and cold). This is what section of the blogpost with the subtitle "Background: Stripbark Bristlecones and Mann’s CENSORED Directory" is about. The "spaghetti graphs" are showing the contributions from the other groups of proxies. Reading the historical links in that section will give you a tour of McIntyre's argument. His argument is not that global warming is not happening, just that much of the proof being offered is statistically very flawed. (It's worth noting the parallels between the criticism of post-hoc screening above, and the suggestion that the bristlecone pines should be screened out. Why one, and not the other? I don't think there's a clear answer.)