New Research on Tree Rings as Indicators of Past Climate

By gregladen on December 17, 2014.

A new study has recently been published that looks at the ecology of bristlecone pine growth at Sheep Mountain, and the tree ring signal those trees produce, at high altitudes in the Southwestern US. This is important because tree rings are an often used proxyindicator for reconstructing past climates. Those who keep track of the paleoclimate research will recall, for example, that tree rings were one of the proxyindicators used by Michael Mann and his team in constructing the famous "Hockey Stick" graph showing a dramatic increase in the Earth's temperature since the onset of industrial times, when the instrumental record (of the last century plus) is put in context of previous centuries. Since then, tree rings have played an important role in past climate reconstruction.

I asked Malcolm Hughes, who was an author on that earlier hockey stick work and an author on the recent study discussed here, how his recent work informs us of the validity of Mann et al, especially in relation to bristlecone pine data used in that early seminal study. He said, “Back in 1999 we (Mann et al) made the best available choices with the information and data we had. Now, more than 15 years later, with a Bristlecone Pine record that extends back 5000 years, the original results hold up remarkably well.”

So, now, let's discuss tree rings a bit and then see what the new paper offers.

Tree Rings And Past Climate

Past climates can be reconstructed by using proxyindicators of past conditions, much like more recent climate can be characterized by using instruments (thermometers, etc.) and data form satellites. One of these proxyindicators is tree ring width. Trees with seasonal growth may produce woody tissue at higher or lower rates depending on a limiting factor, such as available water or temperature. An individual tree may be limited by water availability if it is growing in a certain microhabitat, but a tree of the same species may be limited by temperature if it is growing in a different microhabitat. It is even possible for one limiting factor to control growth for a period of time, then, as conditions change, a different limiting factor takes over. Saplings and small trees growing in a forest may be limited by light, and later, as they grow tall enough (or gaps in the forest canopy open), they may be limited by moisture or temperature.

The tree rings from certain sites seem to properly reflect temperature variability up until around 1960, and after that, the usability of the signal from that proxy can be reduced. This pattern has been noticed in a number of different tree ring records; the phenomenon is widespread enough that it has a name. It is called the “divergence problem.”

Several explanations have been offered to explain the divergence problem, and there is a fair amount of literature on it. It is possible that the post industrial increase in atmospheric CO2 has affected tree growth (acting, essentially as airborne fertilizer) in such a way that the tree ring widths no longer reliably indicate temperature. Changes in the pattern of snow melt at high altitudes, which is where the temperature-sensitive trees are generally found, may affect growth patterns. Changes in minimum or maximum temperature distributions could be a cause. It is also likely that the amount of atmospheric dust (aerosols) has an impact on tree growth, so recent pollution could be a factor. The anomaly could also be an artifact of sampling large trees, in order to sample the longest time periods, if older trees have different growth patterns. In the case of one of the key proxy tree species, bristlecone pines, divergence may have to do with the fact that there are two different growth patterns at the tree’s surface, referred to as strip-bark and whole-bark.

In 2009, Matthew Salzar, Malcolm Hughes, Andrew Bunn, and Kurt Kipfmueller published a paper that looked at a possible divergence problem in bristlecone pines at three sites the American Great Basin. They looked at trees at the upper limit of elevation and found that “...ring growth in the second half of the 20th century ... was greater than during any other 50-year period in the last 3,700 years.” This confirms that whatever the cause of divergence is, it is likely something going on during the most recent decades, which strongly suggests a cause related to Industrial Era pollution or warming. They were able to rule out changes in tree growth patterns and fertilization by added atmospheric CO2. They note that “[t]he growth surge has occurred only in a limited elevational band within ≈150 m of upper treeline, regardless of treeline elevation,” and concluded that “[i]ncreasing temperature at high elevations is likely a prominent factor in the modern unprecedented level of growth for Pinus longaeva at these sites.”

A New Study On How Tree Rings Work

More recently an overlapping set of authors have published an important study (“Changing climate response in near-treeline bristlecone pine with elevation and aspect”) that looks at this problem in more detail. From the abstract:

In the White Mountains of California, eight bristlecone pine (Pinus longaeva) tree-ring width chronologies were developed from trees at upper treeline and just below upper treeline along North- and South-facing elevational transects from treeline to ~90 m below. There is evidence for a climate-response threshold between approximately 60–80 vertical m below treeline, above which trees have shown a positive growth-response to temperature and below which they do not. Chronologies from 80 m or more below treeline show a change in climate response and do not correlate strongly with temperature-sensitive chronologies developed from trees growing at upper treeline. Rather, they more closely resemble lower elevation precipitation-sensitive chronologies. At the highest sites, trees on South-facing slopes grow faster than trees on North-facing slopes. High growth rates in the treeline South-facing trees have declined since the mid-1990s. This suggests the possibility that the climate-response of the highest South-facing trees may have changed and that temperature may no longer be the main limiting factor for growth on the South aspect. These results indicate that increasing warmth may lead to a divergence between tree growth and temperature at previously temperature-limited sites.

Generally, trees from higher latitudes (farther north) and higher altitudes both make better temperature proxies, because the two factors (altitude and latitude) both have temperature as a common thread. You learned this in your middle school Earth Science class. Altitude and latitude mimic each other to a large degree, which is why mountain glaciers can be found on the equator (or, at least, were found there before global warming mostly melted them away). But this new research also shows that topographical position in relation to the sun (south facing vs. north facing) further modify the microenvironment the trees are growing in.

Three earlier studies by Salzer and others (in 2009, 2013, and 2014) show is that the 20th century growth increase at the very highest elevations is temperature related, so in that sense, there has not been a divergence problem in the bristlecone pine, although one may now be emerging on the south- facing slopes, but not on the north-facing slopes near treeline.

The importance of microenvironment is well illustrated in this figure:

This shows the tree ring values for two sampled sites from 1980-2009. Until the mid 1990s, the tree ring values correlate tightly. After this point in time, however, they demonstrate the divergence problem among the samples, in this case, caused primarily by the specific direction the locations are facing (north vs. south).

The most important conclusion of this paper (which is not a reconstruction of past climate, but rather, a study of the ecology of tree ring growth) has to do with how tree ring data are assembled and used. Multiple tree ring samples may be taken from a given site, with the assumption that that site has similar conditions for all the sampled trees, so the assembled and combined tree ring data will have a similar climate related signal. (Note that there is a fair amount of internal variability within a given tree that is hopefully erased when more than one sample from a given site is used). Salzer et al show that at high elevations bristlecone pines can vary from each other considerably if they are sampled form elevations that differ in several tens of meters, or in the aspect (direction) of the slope they grew on, and that this sensitivity is tied to the treeline at on a given slope. And, of course, the position of the samples (as noted above) affects the degree to which tree ring data reflect temperature as opposed to other factors.

We have shown that approximately 60–80 m of vertical elevation can be sufficient to create a change in the climate response of bristlecone pine. Trees below this elevation are not as effective temperature recorders as trees at treeline. Such fine-scale sensitivity, if present at other treeline sites around the world, would have important implications for chronology development and inferences of past climate variability. Treeline site chronologies should be constructed with this vertical heterogeneity in mind. Samples from upper treeline and from trees below treeline should not be mixed to avoid a 'diluted' or 'mixed-signal' site chronology, particularly at treeline sites that occur in relatively dry environments such as the White Mountains of California. Similarly, treeline samples from differing aspects should not be mixed to avoid problems and uncertainties related to potential 'divergences' and to 'dilution'. Interpretations of existing bristlecone chronologies need to take this into account, particularly when these ring width chronologies are used in climate reconstructions.

I asked Malcolm Hughes and Matt Salzer, two of the study authors, how to best characterize this study. They told me that this paper is, for the most part, "...an ecological study. There are no climate reconstructions, rather mostly comparisons of growth from trees growing in different spots on the landscape. There are paleoclimate implications. We still find temperature sensitive bristlecone pine trees at upper treeline; they simply don’t extend down the mountain as far as we used to think. In addition, some of the treeline south-facing trees seem to be less influenced by temperature in recent years than they used to be. The location of the trees, and understanding what environmental variable is limiting growth at that location, is the key to developing accurate paleoclimatic reconstructions from tree rings. Science is a continuous process of improvement.”

Earlier research by an overlapping team also looked at topography. In “Topographically modified tree-ring chronologies as a potential means to improve paleoclimate inference” by Andrew Bunn, Malcolm Huges, and Matthew Salzer (2011) it is noted that

...a mean ring-width chronology from a particular site may be composed of trees from highly varied topographic positions. Such a “topographically-mixed” chronology can be confounded in terms of its climate signal. For example, ring widths of trees that are primarily recording summer temperature might be averaged with ring widths of trees that are primarily precipitation recorders.

That paper details how researchers can use topographic setting to separate different growth series to produce a cleaner sample for developing a temperature proxy. Like the more recent paper discussed here, Bunn et al is an effort to improve the methodology of using tree rings as a proxy.

Science Denialists Can’t See The Forest Through The Tree Rings

Even as the tree-ring proxyindicator expands in size (more samples) and is better understood (from the above mentioned studies) climate science denialists remain entrenched with their assertion that tree rings are bad proxies, or are being used incorrectly. These criticisms are not legitimate critiques of the science, but rather, combine obfuscation and misinformation to muddle and confound thinking about tree rings. An early example of this comes from the kerfuffle known at “climategate” in which electronic communications among climate scientist were stolen and mined for decontextualized quotes that could be used to lie about the science itself and the motivations and activities of the scientists who developed the Hockey Stick curve. Michael Mann chronicles these events in his book “The Hockey Stick and the Climate Wars: Dispatches from the front lines.”

One e-mail Phil Jones of CRU sent to my coauthors and me in early 1999 has received more attention than any other. In it, Jones both made reference to “Mike’s Nature trick” and used the phrase “to hide the decline” in describing a figure ... comparing different proxy temperature reconstructions. Here was the smoking gun, climate change deniers clamored. Climate scientists had finally been caught cooking the books: They were using “a trick to hide the decline in global temperatures,” a nefarious plot to hide the fact the globe was in fact cooling, not warming! ...

The full quotation from Jones’s e-mail was ..., “I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years (i.e. from 1981 onwards) and from 1961 for Keith’s to hide the decline.” Only by omitting the twenty-three words in between “trick” and “hide the decline” were change deniers able to fabricate the claim of a supposed “trick to hide the decline.” No such phrase was used in the e-mail nor in any of the stolen e-mails for that matter. Indeed, “Mike’s Nature trick” and “hide the decline” had nothing to do with each other. In reality, neither “trick” nor “hide the decline” was referring to recent warming, but rather the far more mundane issue of how to compare proxy and instrumental temperature records. Jones was using the word trick [to refer to] to an entirely legitimate plotting device for comparing two datasets on a single graph...

The reconstruction by Briffa, (see K. R. Briffa, F. H. Schweingruber, P. D. Jones, T. J. Osborn, S. G. Shiyatov, and E. A. Vaganov, “Reduced Sensitivity of Recent Tree-Growth to Temperature at High Northern Latitudes,” Nature, 391 (1998): 678–682) in particular ...

...was susceptible to the so-called divergence problem, a problem that primarily afflicts tree ring density data from higher latitudes. These data show an enigmatic decline in their response to warming temperatures after roughly 1960, ... [Jones] was simply referring to something Briffa and coauthors had themselves cautioned in their original 1998 publication: that their tree ring density data should not be used to infer temperatures after 1960 because they were compromised by the divergence problem. Jones thus chose not to display the Briffa et al. series after 1960 in his plot, “hiding” data known to be faulty and misleading—again, entirely appropriate. ... Individuals such as S. Fred Singer have ... tried to tar my coauthors and me with “hide the decline” by conflating the divergence problem that plagued the Briffa et al. tree ring density reconstruction with entirely unrelated aspects of the hockey stick.

Note that there wasn’t a “divergence problem" in Mann et al in the sense of Briffa et al. Mann et al match the observational record very well through 1980, which is the end of the calibration interval (owing to the fact that many proxies drop out after 1980). This is something else the deniers tend to get wrong; they try to conflate the Briffa et al post-1960 divergence problem Mann et al's hockey stick work. There is no such issue with that work, in that there was no detectable divergence through the end of the calibration interval.

Related to this, there was a correction of the Bristlecone Pine data for inflated 20th century increase (which was attributed to CO2 fertilization at the time) in MBH99. So we actually applied a downward correction of the trend in those data. McIntyre doesn’t want people to know that. So need to make sure that is crystal clear.

More recently, climate science denialist JoNova took the new paper by Salzer et al to task using equally mind numbing arguments. JoNova notes that “after decades of studying 800 year old tree rings, someone has finally found some trees living as long ago as 2005. These rarest-of-rare tree rings have been difficult to find ... The US government may have spent $30 billion on climate research, but that apparently wasn’t enough to find trees on SheepMountain living between the vast treeless years of 1980 to now.”

I’m sure the scientists involved in tree ring research would like to know where their $30 billion dollars went, but that’s another story. I asked Malcolm Hughes about JoNova’s implication that there has been next to zero research on or with bristlecone pines over these many years. He said, “This post makes a big deal about the lack of updating of bristlecone pine chronologies since 1980. This is simply wrong. She fails to acknowledge that in 2009 we published on bristlecone pine growth rates in PNAS (Proceedings of the National Academy of Sciences) and put tree-ring data from Sheep Mountain out to the year 2005 in a publicly accessible archive.”

JoNova also implies that the lack of tree ring proxy use for periods after 1980 is somehow suspicious, but as detailed at length above, the divergence problem is, well, a problem. Also, further work such as that reported here is likely to revive some of that data and allow it to be used, eventually. At the very least, future work with high altitude/latitude tree ring data will be improved by these methodological and ecological studies.

Climate science denialist Steve McIntyre has also weighed in on Salzer et all’s research. His post is truly mind numbing, as he treats Salzer et al as a climate reconstruction paper, and critiques it as such, but the paper examines the methodology of tree ring proxy use and the ecology of tree rings. McIntyre shows the same figure I show above (Figure 5 from that paper) and critiques the researchers for failing to integrate that figure or its data with Mann et al’s climate reconstructions. But they shouldn’t have. That is not what the paper is about. Another very recent paper by the same team is in fact a climate reconstruction study (published in Climate Dynamics) but McIntyre manages to ignore that.

Science writer and failed banker Matt Ridley has also applied his abysmal understanding of paleoclimate science with a critique of some of this research.

I’m sure you find these esoteric details of tree ring chronologies fascinating, but there is a point that needs to be made that is even more interesting.

Ever since Mann et al published the famous “hockey stick graph” those in the business of denying or (inadequately) refuting the growing consensus of climate science have made much hay out of both the divergence problem and a sense of suspicion of the tree ring record. For examples of this, read through the comments on this post. If you read comments by those who seem bent on the idea of refuting the reality of global warming, you’ll get the impression that there are only a few tree ring chronologies, we have no idea how they work, they don’t work, that climate scientists pretend they stop working at some point when really they are working but show cooling (which we know didn’t happen because we have thermometers) and, generally, that tree ring science is some sort of exercise in voodoo.

What has really happened, however, is that tree ring data have behaved pretty much as any other paleoclimate proxy behaves. There are conditions under which any given proxy works, and there are conditions under which the proxy can’t be trusted and should not be used. Decades ago, when the Hockey Stick was first formulated, the loss of signal in the tree ring record was somewhat mysterious, though numerous good ideas explaining it were out there. Subsequently, there has been a considerable amount of research adding new tree ring data, and some of that research has focused on teasing out the methodological and ecological details of this particular proxy. Interestingly, the last 10 years or so of tree ring research has failed to force the conclusion that tree rings are not good sources of past temperature data; the divergence problem is replicated in other records showing it again to be a recent phenomenon; change in regional (and global) temperature is increasingly implicated as the cause of the divergence problem; and much finer details of how this all works, at the scale of tens of meters elevation and at the level of details of topography have been worked out.

References and related items

Briffa, K.R., F. H. Schweingruber, P. D. Jones, T. J. Osborn, S. G. Shiyatov, and E. A. Vaganov, “Reduced Sensitivity of Recent Tree-Growth to Temperature at High Northern Latitudes,” Nature, 391 (1998): 678–682.
Laden, Greg. 2014. Matt Ridley, Anti-Science Writer, Climate Science Denialist blog post
Mann, Michael E. (2012-01-24). The Hockey Stick and the Climate Wars: Dispatches from the Front Lines (p. 263). Columbia University Press. Kindle Edition.
Mann, Michael E. The Hockey Stick and the Climate Wars: Dispatches from the front lines.
Mann, Michael E., Raymond Bradley, Malcolm Hughes. 1998. Global-scale temperature patterns and climate forcing over the last six centuries. Nature 392.
Matthew W. Salzer, Malcolm K. Hughes, Andrew G. Bunn, and Kurt F. Kipfmueller. 2009. Recent unprecedented tree-ring growth in bristlecone pine at the highest elevations and possible causes. PNAS 2009 106 (48) 20348-20353; published ahead of print November 16, 2009, doi:10.1073/pnas.0903029106
McIntyre, Steve, 2014, “Sheep Mountain Update” blog post
Ridley, Matt, 2014, “Science is being corrupted by political bias” blog post.
Salzer, Matthew, Evan Larson, Andrew Bunn, and Malcolm Hughes. 2014. Changing climate response in near-treeline bristlecone pine with elevation and aspect. Environmental Research Letters 9(11)
Skeptical Science. “Clearing up misconceptions regarding 'hide the decline'” web page

Wikipedia. The Divergence Problem.

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Thanks for the detailed explanation.

Amazingly helpful, bookmark-worthy resource on tree ring proxies. Thank you for all the hard work you do. This is one of my favorite blogs. While you may not think most readers will be thrilled to read about dendrochronology, there are people like me who eat it right up. Don't be afraid to delve into the weeds and finer details every now and again.

On a side note, very unfortunate to find out about Matt Ridley. The Red Queen is one of my all-time favorite non-fiction books. This saddens me, to say the least.

Daniel, if this is helpful to you, you need to study this subject more. The reconstruction makes no sense because the proxies go down significantly after 1980 but the temperatures goes up. That simply makes no sense.

Percival, all you really need to do is actually read the post!

Some tree ring sequences are subject to an effect in recent decades that makes them not very useful. Others are not subject to this effect. This research, in part, helps to understand what is going on there. In any event, what actually makes no sense is totally rejecting a proxy because under some conditions they don't work well. Climate science deniers would like that because all proxies, depending on where they are sampled, etc., don't work well sometimes, so all proxies would have to be rejected. What also makes no sense is using proxies without proper methodological rigor.

You appear to be asking for one or the other, but you can't have either because both would be bad science.

But the proxies should be distinguishable from noise, right?
As long as you have proved that

Otherwise we are in the same boat as that guy who makes zero sample inferences..forgot his name now a distinguished warmist academic somewhere (there are many)

lol

another warmish who goes for "moderation"..they're all the same aren't they

1. Thanks. Helpful explication.

2. I have dealt with McIntyre. He's annoying. Don't let him get to you.

3. Prefer not to mix in the adjectives (abysmal) and the like. Just take down the arguments. But it gets hard to read when the adjectives about people are mixed in (McI does this a lot...turns me off of even parsing his points to weed past that).

4. I still wonder to what extent this work calls into question earlier chronologies. How many were in Mann's (or other) compilations. Good, bad or indifferent...just how much impact.

5. The idea that treeline might change with a warming and thus temp responsiveness of tree proxies is not new and is a pretty fundamental concern for use of tree rings as proxy. Coral does not have this issue.

6. One fundamental question I have on the divergence is if it could show an issue of out of sample falsification. IOW, we got "decent" chronologies by matching to a broad linear trend (not the wiggles, so much) over last century. But it doesn't hold up out of sample. Perhaps indicating over selection (e.g. same issue exists with stock picking models). I'm not ASSERTING this happened. Just as a scientist, it is the thing to check, beware of, etc.

Mr. Laden, I wonder if perhaps you got something backwards in your post.

My understanding is that the "divergence issue" has to do with tree rings getter *narrower* after the 1960s in some samples, thus (wrongly) indicating that nearby temperatures had gone down, when we know from temperature records that in fact they have gone up.

However, in your post you discuss the 2009 paper, writing "...' ring growth in the second half of the 20th century … was greater than during any other 50-year period in the last 3,700 years.' This confirms that whatever the cause of divergence is, it is likely something going on during the most recent decades, ..."
Here, you seem to be suggesting that recent growth rings are *wider*, which is the opposite of the "divergence problem".

I'd welcome any clarification you can provide.

"These results indicate that increasing warmth may lead to a divergence between tree growth and temperature at previously temperature-limited sites. "
So the same thing could have happened in the MWP etc.?

The significance of the decline in some tree ring responses to increasing temperatures since 1980 is completely evaded. Here is the significance:

The most striking feature of Michael Mann's "hockey stick" tree ring reconstruction is not the upward-soaring blade on the modern end -- rather, the most striking thing is the relatively flat long historical handle. For this flat handle wipes out the Medieval Warm Period (MWP) -- and wiping out the MWP is important to global warming's central argument, which argument being the claim that ONLY an increasing CO2 level can explain modern warming. If there HAD been a MWP, this would negate the central argument, because it would demonstrate that something OTHER than CO2 HAS caused warming in the past.

And THIS -- the wiping out of the MWP -- was the most welcome aspect of Mann's hockey stick reconstruction. BUT -- and here is the rub -- if some tree rings can indeed cease to be responsive to temperature and fail to show rising temperatures, as has clearly happened since 1980 -- the how on earth can you know for a fact that the MWP did not occur? How do you know the tree rings didn't simply go into a "pause" during the MWP, or at any other time for that matter, just as they have since 1980?

The answer is, you don't know it -- you only assume it -- because it fits the narrative you are pushing.

ptw, if your questions were understandable or in reasonably good faith I might address them. At this point I think you are just yammering.

moo: I provide MH's assessment of earlier chronologies. All earlier chronologies are always in question. If you feel that new information calls into question an earlier chronology, redo the chronology, get a peer reviewed paper out of it. In many ways, many new studies are re-dos of earlier work. This is an ongoing process.

The newness of tree ring response to altitude and temperature is indeed not new. This research, however, is new. As described.

I'm not sure how you can be asking for "out of sample" verification after actually considering this post and any of the other literature. Totally misses the point.

Mondoman, the authors of this overlapping set of papers do not call the sheep mountain change in response a divergence problem (see above). Im' making a more general point about the validity of the record.

AntonyIndia: The MWP is a regional phenomenon. It does not seem to affect Great Basin bristlecone pines. You might be thinking of a discredited and discarded version of climate history in which the MWP is both very strong and very global.

Michael, you'd have a case if there was only one proxy on Earth. There is not only one proxy on Earth. That is how, on Earth, we can know that. Not assumed. Not a something that fits a narrative you imagine.

GL - in my post above, I wrote that you noted about the 2009 paper:
"..This confirms that whatever the cause of divergence is, it is likely something going on during the most recent decades, …” (implying to me that you think this paper says something about the divergence problem)

However, in your (very prompt!) reply, you write "...the authors of this overlapping set of papers do not call the sheep mountain change in response a divergence problem (see above)...."

I guess I remain confused about your overall point. Is it perhaps that tree rings are known to substantially diverge downward from temperature records (the "divergence problem" known for decades) and now have also been shown to substantially diverge upward from temperature records (the recent Sheep Mountain papers)?

They don't actually substantially diverge.

You might not know this, but when a tree ring record is produced from a particular are, several samples are combined (as discussed above) to dampen random or irrelevant internal variation. When you look at the specific tree ring cases brought out to show how a very small and differentiated sample behaves, that is what is being teases out. That is not a climate record, it is a study of ecological variation.

The point of the research being discussed here is to improve sampling and interpretations to account for these smaller scale variations.

In order to understand this you need to step away from the denialist yammering which is highly misleading and designed to confuse. For instance, insisting that a using a proxy under conditions where it is known to not work proves that the proxy does not work, so why don't they use the proxy under the conditions that it doesn't work??!?!?!?

Greg, you gave exactly the response I expected. Please name these other proxies that you think rescue Mann's reconstruction.

Prediction: You will cite other allegedly "independent" reconstructions "confirming" Mann's -- and when you do, I'll show you how they use the exact same obviously flawed reconstructions. McIntyre has shown all this over and over.

Michael, I'm not going to play some sort of game with you. If you have something specific and constructive to say, say it. Otherwise push off.

I guess I didn't phrase my questions as clearly as I could have -- sorry!
Q: You noted above about the 2009 paper:
“..This confirms that whatever the cause of divergence is, it is likely something going on during the most recent decades, …”
What is the "this" here in the 2009 paper that suggests to you that the divergence problem's cause is relatively recent? Or, if "the cause of divergence" isn't referring to the "divergence problem", which divergence does it refer to?

Hope that's clearer!

The most recent paper, Salzer, Matthew, Evan Larson, Andrew Bunn, and Malcolm Hughes. 2014. Changing climate response in near-treeline bristlecone pine with elevation and aspect. Environmental Research Letters 9(11), looks at causes of variation in tree ring signals, confirming that there is a sensitive zone for PCP's to show a temperature signal, that the sensitive zone is probably smaller than previously thought, that aspect is important, etc. The earlier paper by the same group shows that sampling widely will probably incorporate both the variation one is trying to dampen (good) and some variation that could actually be controlled for and that should be partitioned out (so too broad of a sample is bad). Identifying tree ring samples or signals that are clean for temperature, and accounting for the "divergence problem" are kind of the same thing, but for the latter, the problem appears at a certain point of time (recently) as opposed to being intrinsic to the sample. More specifically, if the divergence problem is (as it seems to be as other factors are ruled out) temperature, which recall is related to alt/lat, then the alt/lat/aspect research is probably very relevant to it.

Greg:
Do some of your commenters here think this image represents the Earth's global temperature history, and that the MBH99's hockey stick was intended to hide that?

OK, I appreciate your efforts, but it seems clear the whole "divergence" issue is something that can't be covered in a single blog entry, and will demand some more detailed research on my part. Your list of references is very welcome and something that I hope other blogs will emulate.

I'll also note in closing that the facts and links you mention are very useful to someone trying to get to the bottom of all this, but the constant use of epithets like "denier" is unhelpful (and immature) and likely contributes to the impression common in some other sciences (I'm a biologist) that climate science still has some "growing up" to do.

I come here on a link from Jo Nova's site. Name calling is not a scientific endeavour. If you are really interested in what causes the earths climate to change, you need to look else where, it is not CO2. Try Jupiters alignment to the sun and the suns orientation to the galactic centre, a little bit of celestial mechanics and a profound knowledge of the charge field that controls everything will give you the time table for the ice ages. The forces that control our solar system do not give a bugger what we do.

Actually, Wayne, I've not done any real name calling. It is a new strategy among denialists to point to arguments against them and call it name calling.

Not that there is anything wrong with labeling people where appropriate. For example, you, sir, are some kind of kook. I might be wrong about that, but by the stars I think I'm right.

Mondoman, in biology the evolution deniers just have a different epithet: cdesign proponentsists.

Greg,

I didn't ask you to "play some sort of game" with me -- I asked you to name these other reconstructions that you know for a fact to have been infallible in the past. Surely that is a fair question -- if some trees can suddenly begin to diverge from the instrument temperature record -- which is most assuredly the case since 1980 -- how can one know that these same tress did not diverge in the past? How can one know that OTHER trees in other reconstructions have not also diverged?

There is, after all, evidence for the existence of the MWP. It is not a fiction invented by "climate science deniers".

I am not "denying" the science -- I am asking for compliance with science. The reliability of tree rings as temperature indicators is clearly in question, not merely because the divergence issue but because there are other known factors that influence tree growth, such as rainfall, soil conditions. insect infestations, CO2 fertilization, etc.

On what possible grounds do you throw out all the questions about tree rings and simply assume past reliability? To do so is surely an act of faith, not science.

Have you read this, by the way:

http://www.uoguelph.ca/~rmckitri/research/McKitrick-hockeystick.pdf

Or try this:

http://climateaudit.org/2005/02/20/bring-the-proxies-up-to-date/

Science requires that the evidence be explained, not assumed away.

Michael, I referred to other proxies, you are asking me for the other reconstructions. Perhaps you don't know this. A proxyindicator (proxy for short) is a system that provides an index of some sort, depending on conditions, to what might otherwise be an instrumental measurement of something (rainfall, temperature, etc). A proxy is not a reconstruction.

This could explain a lot of your misunderstanding.

The divergence issue does not impact at all on the reliability of tree rings as a proxy. All proxies have a range of conditions and circumstances under which they work. For example, for dating (yes, dating techniques are essentially the same thing as proxies) 14C has a limit on the time range over which it useful. Your statement about the reliability of tree rings because of the divergence issue (or other issues) is like saying that 14C dating cant' be used because it does not work for material, say, around 200,000 years ago.

The vast, vast majority of tree ring data can not be used to reconstruct temperature. Most of it simply does not carry that signal. It wasn't collected to look at temperature, it has other uses, etc. Also, many tree ring sequences look at climate related data other than temperature, and carry virtually no temperature signal as well.

The MWP is real, but it is not what many say it is. It is not global, for example.

I'm not sure if you are denying the science, but you are demonstrating that you know very, very little about it.

Now, perhaps you were asking for other climate proxies. (Since that is what you mentioned and you seemed to be asking for more, even though you called proxies reconstructions).

Besides tree rings there are CO2 levels in ice cores, Coral growth patterns, 18O/16O ratios in ice cores, shells, and other materials, surface foram data preserved in sea cores, pollen in lake cores, a range of elemental, magnetic, etc. signals in cores that indicate things like rainfall/erosion/etc. (less direct for temperature but still used), dropstones in sea cores, ocean sediment rates, borehole temperatures, a wide range of carbonate precipitate methods at a wide range of accretion sites (springs, in caves, etc.) including soil carbonates, and elemental (including stable isotope) analysis of a wide range of organic material. To name a subset of the proxies.

Before you ask me to provide you with more information about these proxies (or otherwise do your homework for you) I'll give you this link: http://bit.ly/1sWvlWd

Translated to English from "scientific": "Tree rings show the trend we want if we pick the trees carefully enough!."

It is hard for me to see any signal coming out of the noise beyond saying that a thick ring was a good year for some specific tree in some specific location. I can't see the forest for the trees.

How about addressing the issues raised by McIntyre without resorting to name calling. You should be capable of doing that shouldn't you?
I'm sure McIntyre and Nova are quite capable of reciprocating with equally offensive name calling, but the truth of the matter is that name calling is a particular technique employed in order to avoid dealing honestly with embarrassing questions.
When you are able adopt a civil approach to those with differing opinions, then we might expect to hear something of value from you.
I will not be holding my breath.

Greg, you state
The divergence issue does not impact at all on the reliability of tree rings as a proxy. All proxies have a range of conditions and circumstances under which they work.

Can tell us what those conditions are for bristlecone pines and whether they held for all the years back to 1000AD. I would be surpised if you can because there is no definitive explanation of the breakdown between bristlecone ring growth and temperature since 1980 when we have lots of supplementary information. Until we can explain that breakdown (and I don't mean loose speculations about what might have caused it I mean solid evidence) we are not in any position to say anything about temperature prior to the instrumental period from this purported evidence.

Surely that is a fair question — if some trees can suddenly begin to diverge from the instrument temperature record — which is most assuredly the case since 1980 — how can one know that these same tress did not diverge in the past? How can one know that OTHER trees in other reconstructions have not also diverged?

Michael... You do realize, I hope, that tree rings are validated and calibrated. Right? Dendroclimatologists are not just taking any any old tree rings and saying they represent temperature.

There's a huge amount of work that goes into the validation process.

I am not “denying” the science — I am asking for compliance with science.

When you automatically reject researchers' conclusions without having a basic understanding of how the science works... That's denial.

The reliability of tree rings as temperature indicators is clearly in question

Can you please provide us the published research that makes such a claim? Or is this something you're just making up?

I would also note here, Michael, that neither McKittrick nor McIntyre are trained in dendroclimatology. You're sharing blog posts which are not published research.

What you should also note is, neither of these individuals has been able to published their own temperature reconstructions of the past, while dozens of other researchers have been genuinely skeptical of earlier dendro work and taken it upon themselves to test the results.

Each and every time researchers get the same answer: The Hockey Stick.

The unjustified but frequent, sneering use of ad hominem language proves that, at heart, you really are a nasty person.

John, and others, really, you need to tell me what the basis of your argument is. What "names" have I called anyone exactly? Before I continue with that line of conversation I'll need to know that.

This post is only marginally about the denialist claims, though, so I'm not sure I'm going to pursue that. You don't get very far when dealing with smarmy conversations like that.

John Garrett: ROFLMAO. Good one!

>Rob Honeycutt
"When you automatically reject researchers’ conclusions without having a basic understanding of how the science works… That’s denial."
I don't see that in most of the skeptical comments here. The key question seems to be: How can we have confidence that tree rings indicate temperature before the calibration period when they diverge from instrumental data after the calibration period? Properly asking the question does not require knowledge of climate science, just logic.
Possibly understanding the answer does require some knowledge, but I have yet to see a clear answer here.

Marco,
In grown-up sciences like biology, people talk about the research; they don't spout psychobabble about "denial" or conspiracy theories about funding or talk about "cdesign", whatever that is. None of those things are relevant to the science, although they can make for messy foodfights!

RobH, you're misconstruing science when you note that "...neither of these individuals has been able to published their own temperature reconstructions of the past...". Just as a researcher doesn't have to figure out the actual function of a gene in order to show that another proposed function is not correct, one doesn't have to publish a temperature reconstruction to show that another reconstruction used bad data or inappropriate calculations.

One of the major flaws in current paleoreconstructions seems to be that proxy-domain experts (e.g. those collecting data on tree rings or varves or speleothems) often lack the personal statistical expertise needed to assemble that data into a reconstruction, and thus they use math they don't understand, producing poor-quality reconstructions.
In biology this problem was recognized decades ago, and led to the widespread practice of collaborating with statistics experts on work involving statistics. There's even a specialty called "biostatistics". Seems like we need a "paleostatistics" specialty.

"people talk about the research". Hold it right there!

With that sentence, you are pre-supposing a political ability for "people" to do just that. I.e., this blog might be outlawed in places (N. Korea comes to mind..) and you thrown in jail for discussing things like this publicly!

Ergo, you cannot separate the "talking about the research" from the politics that surround and influence the "talking about" that's going on. Else it could just be suppressed completely, and there would be no "talking about" no matter how good or how true the research.

As a consequence, those who are "doing the research" and want to "talk about it" are forced to (like it or not) also deal with the politics, and politically motivated speech & tactics, of those around them who wish to (for whatever reason; N Korea keeps coming to mind) suppress the "talking about the research" because they have political agendas that are frustrated and threatened by the implications of the results.

So, sorry, these things you list ARE relevant to science, on the whole (as a direct result of "science" being conducted by human beings), and that's unfortunate, in a way.

I suspect that you have been dealing with "sciences" that do not trigger these types of aggressive political attacks. Well.. Welcome to the Big Leagues!

Mondoman...

Just as a researcher doesn’t have to figure out the actual function of a gene in order to show that another proposed function is not correct, one doesn’t have to publish a temperature reconstruction to show that another reconstruction used bad data or inappropriate calculations.

But one does need to understand the field they're commenting on in order to get research published. M&M have published a very few papers on this area, and none of them has stood the test of time.

What you would expect, if these guys had actually figured out something substantive about temperature reconstructions and tree ring, is that their results would be born out by following research. So far, everything that has been published has shown MBH's results in 98/99 to be robust. That suggests that M&M were either flat out wrong in their conclusions or their conclusions were so insignificant as to have no effect.

"One of the major flaws ... seems to be ..." You forgot to cite the research that supports your pre-supposition. And I suspect you don't have a statistically relevant chance of proving your point...

One of the major flaws in current science criticism seems to be that self-styled experts often lack the personal field-related expertise needed to assemble a case against those they are criticizing, and thus argue against methodologies they don't understand, using poor arguments to construct strawman attacks.

But, hey, whatever...

One of the major flaws in current paleoreconstructions seems to be that proxy-domain experts (e.g. those collecting data on tree rings or varves or speleothems) often lack the personal statistical expertise needed to assemble that data into a reconstruction...

Far from it. You're making the completely absurd claim that no one in the entire field of dendroclimatology understands their field of research.

It's far more likely (and has been clearly shown) that people who do NOT have a background in dendro work are the one's who do not understand the special statistical circumstances that are relevant to the field.

Again, if there were issues with the techniques used in this field that M&M had turned up, that would have shown up in the subsequent reconstructions since their challenges. M&M could certainly, by this time, produced their own reconstructions, but they've failed to do that.

The only possible conclusion that anyone can rationally come to is, the hockey stick is the result of robust research. It's been upheld over and over and over again.

RobH, one of the key skills in science is attention to detail. In that spirit, I'll note that I wrote "...often lack the personal statistical expertise needed to assemble that data into a reconstruction...", which is of course very different from "...making the completely absurd claim that no one in the entire field of dendroclimatology understands their field of research."

However, perhaps I'm just not up-to-date on proxy reconstructions. Perhaps you could suggest 3 or 4 recent (post-2010) reconstruction papers that include references to establish the validity and domain applicability of the statistical techniques they use, or at least include statisticians as co-authors (as is done in biology)?

RobH, you note that "...none of them[M&M publications] has stood the test of time."
What do you see as the errors in "McIntyre, S., and R. McKitrick (2005), Hockey sticks, principal components, and spurious significance, Geophys. Res. Lett., 32, L03710,
doi:10.1029/2004GL021750" ?

Mondoman... First off, you're not going to accept anything that I present as an error, which is fine. People frequently disagree about methods and results in science all the time. BUT, what one expects is, if someone challenges research results, if those challenges are substantive they'll bear out in subsequent research.

That hasn't happened.

What HAS happened is, with each and every subsequent attempt to reconstruct millennial global temperature the results have been consistent with MBH's original research.

Mondoman...

However, perhaps I’m just not up-to-date on proxy reconstructions.

I would suggest reading AR5 chapter 5...

http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter05_FINAL…

Rob, in science when folks make claims such as “…none of them[M&M publications] has stood the test of time," they have specific flaws/errors in mind. Not being able to point to any such flaws in a paper changes things from science to just playground gossip.

Regarding my request for 3 or 4 recent paleoreconstruction papers that did establish a foundation for the statistical methods they used, if you don't know of any, it's fine to admit that -- I don't know of such either.

in science when folks make claims such as “…none of them[M&M publications] has stood the test of time,” they have specific flaws/errors in mind.

You're missing the point. There are lots of flaw and errors that have been pointed out, and I could waste both of our time by posting a long list of citations, but that hardly matters.

What matters is whether or not M&M's conclusions have changed anything in subsequent research. Are you honestly complaining that MBH's used bad methods to get correct results?

As for the 3 or 4 recent papers, that hardly matters either. What matters are the results. Do the results support or contradict previous results. So far we have NO results since MBH's original work that contradict their conclusions, AND we have a couple dozen reconstructions that support MBH's original work.

If M&M's work had had any significant results – if they'd produced something that actually changed how researchers do their work and changed our thinking about the relevant science – it would be abundantly apparent in subsequent research.

As it is, M&M have had no impact on any aspect of millennial reconstructions. Zero.

RobH, if there really are lots of flaws and errors in M&M's GRL 2005 paper, it should be easy for you to name one. Your seeming inability to do so makes your claim unscientific.

Whether or not M&M's conclusions have changed anything in subsequent science is not science, but psychology or perhaps history of science. Science is about facts and results, not people's actions.

You seem to focus on "results" and dismiss how they were arrived at as unimportant. In science, the validity of conclusions depends on the methods and data used. "Results" on their own are useless, as they are of unknown validity. In fact, this concept is so fundamental to science that many Ph.D. programs require predoctoral students to take a class in how to analyze scientific papers in order to determine whether and how well the data and methods used support the claimed conclusion. Many scientists, when reading a paper, read the data and methods sections first so as not to be swayed by the authors' claimed "results" until after they've made their own determination of what is supported.

The M&M GRL 2005 paper isn't too long. Why not read it yourself and see what you think of the methods and data? http://onlinelibrary.wiley.com/doi/10.1029/2004GL021750/full

Instead of reading blogs by non-dendrochronologists, people could:

0) Read Thomas M Cronin's Principles of Paleoclimatology(I have 1999, but I think I saw newer edition at AGU).

1) Read Ray Bradley's Paleoclimatology - Reconstructing Climates of The Quaternary(1999 is the edition i have, there is a new one).
Chapter 10 (pp.397-438) is on dendrochronology (whereas Cronin's is a bit more spread around).

Bradley(1999) the book where
a) Wegman+Said plagiarized a few pages, then inverted the key conclusion they didn't like.

b) Used a few tables, did cite him there, but misspelled the title as "Quarternary", "phenology" as "phonology" and "speleothem" as "speleotherm", i.e., they were clueless about basic terms of a field they were trying to criticize. Spelling errors happen, but this was absurd.

c) and of course, they were clueless about the close relationships among many paleoclimatologies and statisticians. They then copied McInhtyre's faulty code, including the 100:1 cherry-pick to get the preferred graphs.

Then McIntyre invented claims that Bradley had plagiarized Hal Fritts, but didn't understand that textbooks are not original research, and didn't examine the extensive list of Copyright Acknowledgements on pp.595-599. Fritts was furious, but not at Ray.

2) People could attend the yearly AGU conference in San Francisco, and match their knowledge versus folks like Mann, Bradley, Malcolm Hughes, or guys like Doug Nychka or Gene Wahl. Bradley had too many trips to make the one just finished, but the others were there.
Malcolm talked about progress on the general topic of this post a few years ago ... One can hear the world's top people talk about research that often isn't published yet, and ask them questions about it.

AGU2014 had at least 7 dendro {chronologuy|ecology} talks/posters.

Bradley in particular discusses at length the challenges in dealing with each kind of proxy, and the techniques people use to find useful proxies and extract signal from the noise. Huge chunks of the book are that sort of thing.

People repeat worries about methodology regarding a field where they don't seem to have read even basic textbooks.

This is like suddenly realizing that airplanes are heavier than air, and have aerospace engineers ever thought of that? Most of what blog commenters worry about was already in textbooks 15 years ago.

Again, Mondo... It's rather pointless but if you really need to have a catalog of errors:

http://deepclimate.org/2010/02/04/steve-mcintyre-and-ross-mckitrick-par…

http://deepclimate.org/2010/03/10/mcclimategate-continues-yet-another-f…

http://www.realclimate.org/index.php/archives/2004/12/false-claims-by-m…

http://www.realclimate.org/index.php/archives/2005/01/on-yet-another-fa…

And I could go on and on...

But once again, you're missing the point.

IF there had been something truly substantive that was presented by M&M – results that would actually change our scientific understanding of millennial temperature reconstructions – it would show in the subsequent research.

M&M has been a completely pointless footnote in the body of research. Their research has been very effective at getting those prone to denial up in arms. But that's about it.

Scientifically, M&M has done nothing to change the scientific understanding of past climate. Zilcho.

Whether or not M&M’s conclusions have changed anything in subsequent science is not science, but psychology or perhaps history of science. Science is about facts and results, not people’s actions.

This is just a bizarre comment. The whole point of science is to expand the body of human knowledge! That is what the word means! "...from Latin scientia, from scient-, sciens having knowledge..." M&M changed absolutely nothing about our knowledge of millennial temperature.

On the other hand, MBH98/99 absolutely did change the body of human knowledge. And every subsequent reconstruction since then has confirmed and furthered that branch of human knowledge.

http://deepclimate.org/2010/11/16/replication-and-due-diligence-wegman-…
http://moyhu.blogspot.com/2011/06/effect-of-selection-in-wegman-report…
http://moyhu.blogspot.com/2014/09/theres-more-to-life-than-pc1.html
http://moyhu.blogspot.com/2014/09/what-steve-mcintyre-wont-show-you-now…
http://moyhu.blogspot.com/2014/10/analysis-of-short-centered-pca.html

Summary: bad statistics weren't enough, M&M needed a 100:1 cherry-pick to produce the graphs they wanted. (Wegman+Said used the same code, modulo some portability tweaks.)

As exercise people might check an original McIntyre post and look for a multiply-false citation (in academe, called academic fraud) needed to make an unsupported and very dubious claim have even the remotest plausibility.

Here's my favorite error from M&M...

Their method, when tested on persistent red noise, nearly always produces a hockey stick shaped first principal component (PC1) and overstates the first eigenvalue.

Later it was found out this result was a function of M&M improperly stripping the signal from their red noise.

Not just an error in their paper. A critical error that undermines their entire paper. And these are the guys you think know more about statistics than the researcher who work in the field.

http://www.people.fas.harvard.edu/~phuybers/Doc/hockey_grl2005.pdf

JM - Thanks for the useful-sounding references! I had looked at one of Fritts' books a few years ago, but it was pitched at what seemed like an introductory undergrad level and didn't include much math.

RH - you claim "IF there had been something truly substantive that was presented by M&M – ... – it would show in the subsequent research."
In biology, there are numerous examples where this wasn't true (at least for a decade time horizon); I see no reason to believe that climate scientists are more perfect beings. :)
In any case, your argument is about a group of people's reactions to a paper, not about the facts and methods of the paper itself. As such, your argument is psychological, sociological or perhaps political in nature, not scientific.

"In grown-up sciences like biology, people talk about the research; they don’t spout psychobabble about “denial” or conspiracy theories about funding or talk about “cdesign”, "

Yes they do, Mondoman. When yet another member of a congress explains how evolution is "just a theory", biologists talk about the denial of that MoC. When yet another school boards needs to deal with a proposal to teach ID or even outright creationism in science class, biologists talk about denial. When yet another anti-vaxxer spouts nonsense about the immune system, biologists talk about the denial of science. When anti-GMO activists claim those genes are soooooo dangerous, biologists talk about the denial.

It appears you are in denial of this denial...

Rob Honeycutt claims that Huybers found a critical error in the M&M GRL paper. Before getting too excited I suggest he read the M&M reply in GRL. The link is on the front page of the Climate Audit website. I can't make out from Rob's description of the supposed error exactly which of Huybers criticisms he is endorsing, but I assume it's the RE significance levels, which Huybers claims are reduced if variance scaling is used. M&M show that if rescaling (a step not described in MBH98) is used together with the MBH reconstruction method the significant RE vale drops only from 0.59 to 0.54, not to 0.0 as MBH found. There are a series of contemporary posts on this at CA. The most relevant seems to be this one
http://climateaudit.org/2005/09/17/huybers-2-re-scaling/

Perhaps the best overview of the Huybers comment from the M&M side is the first post in the CA series here

http://climateaudit.org/2005/09/16/369/

Rob Honeycutt December 21, 2014
" The reliability of tree rings as temperature indicators is clearly in question"
"Can you please provide us the published research that makes such a claim? Or is this something you’re just making up?"
Is this good enough Rob?
Greg Laden December 21, 2014
"The vast, vast majority of tree ring data can not be used to reconstruct temperature. Most of it simply does not carry that signal. It wasn’t collected to look at temperature, it has other uses, etc. Also, many tree ring sequences look at climate related data other than temperature, and carry virtually no temperature signal as well"
Clearly not made up

Greg
“The vast, vast majority of tree ring data can not be used to reconstruct temperature. Most of it simply does not carry that signal.
I think you mean that the carried data is too hard to dissect out from the other conflating values in most trees.

"There is evidence for a climate-response threshold between approximately 60–80 vertical m below treeline, above which trees have shown a positive growth-response to temperature and below which they do not "

So fortunately a small group of tree rings in an extremely specific location behaved in accordance with other proxies over an extremely specific time interval and though they have not shown this behavior since, in fact behaving as the vast, vast majority of trees have done over time, we can use them as a proxy for temperature.
OK, It is Christmas . And they are bristle-cones.

Greg,

Your response seems to be a collection of red herrings, beginning with your latching onto what you think is my ignorance of proxies versus reconstructions and continuing with all this other irrelevant information about what does and does not work as a proxy, the proxies beyond tree rings, etc., accompanied by the condescending claim that I must know “very, very” little about climate science. In the middle of all this you insert this assertion:

“The divergence issue does not impact at all on the reliability of tree rings as a proxy.”

This assertion is surrounded, not by supporting evidence, but by what I can only interpret as an attempt at argumentum ab auctoritate or argumentum ad verecundiam in the hope of silencing further questions.

What you are evading is that extrapolating results outside the verification period is rendered logically invalid if outside-the-period samplings reveal divergence – which is exactly what we have seen. Can you address that specific issue?

Rob said:

“Michael… You do realize, I hope, that tree rings are validated and calibrated. Right? Dendroclimatologists are not just taking any any old tree rings and saying they represent temperature.”

Yes, Rob, I realize tree rings are validated and calibrated – the issue is, can results be reliably extrapolated backward in time, when they clearly cannot be extrapolated forward ( at least not for the few that have been updated since 1980. I am with Steve McIntyre on that issue: update the proxies!) Can you address this issue?

The insistence that the divergence phenomena has no impact on the validity of proxy extrapolations is like the insistence that the divergence of the GCMs from observations has no impact on the models’ validity. It is science 101 that when observations – i.e. reality – contradicts one’s claims, the claims must be modified or abandoned. Why that point seems beyond climate scientists these days is a mystery to me.

Is there any good links to peer-reviewed studies on the Medieval Warm Period?

Otherwise talking about what proxies may or may not have been valid during this time is an "argument from ignorance".

Maybe try checking out this page, which cites some peer-reviewed items: http://www.skepticalscience.com/medieval-warm-period.htm

Harry (62) This actually reminds me to note that we should not be calling it the "Medieval Warm Period" because a "Period" is bigger, more global, etc. It is, rather, better referred to as the "Medieval Climate Anomaly."

Regional temperatures during the MCA are lower than during the so-called Little Ice Age over some areas, though for the most part the MCA is warmer than the LIA. But it was not warmer than the present.

The MCA's relative temperatures based on 60-90 climatology was cooler across almost all of eurasia, oceania, well over half of Africa, most of South America, half of North America. In the oceans, the sea surface was a tiny bit warmer in parts of the pacific, much warmer in the North Atlantic, but across the vast majority of the ocean, cooler. So, prior to the most recent, and warmest, decades, the MCA was a cool period compared to pos-industrial. When we add in the last couple of decades, (1991-p) the MCA is not even close.

Climatehawk1 gives a good start on where to look. This paper is key:

http://www.meteo.psu.edu/holocene/public_html/shared/articles/MannetalS…

But the deniers will automatically not like it because Michael Mann is an author.

You can also look at Zhou, Li, Man, Zhang and Zhang, 2011. A comparison of the Medieval Warm Period, Little Ice Age and 20th century warming simulated by the FGOALS climate system model which concluded: " Relative to the pre-industrial control run, the MWP experiment exhibits a warming of 0.40°C over most parts of the globe, except for the mid-latitude North Pacific and Eurasian continent. The warming center is located in the high latitudes of northern America, with the magnitude of 1.0°C. Both the MWP and 20CW experiments exhibit a polar amplification response. The warm anomalies in the high latitudes of the Northern Hemisphere are stronger than those in the Southern Hemisphere. The magnitude of the natural warming during the MWP is weaker than that during the 20th century. "

Climatehawk1, Greg Laden, thanks for the info.

I was examining the idea Michael Smith's speculation that tree ring proxies had "divergence problems" during the MCA. I am aware that he is trying to discredit the hockey stick graph - trying to use the MCA is a common tactic along with the Conspiracy Theory that the IPCC removed the MCA from it's later reports. But I was curious if there is much evidence for the MCA in the first place.

Yes, Rob, I realize tree rings are validated and calibrated – the issue is, can results be reliably extrapolated backward in time, when they clearly cannot be extrapolated forward

You clearly don't know the first thing about how tree ring data is validated since it's not just through correlation with modern temperature records.

Mondoman... "I see no reason to believe that climate scientists are more perfect beings."

I see no reason to believe that the entire field of dendroclimatologists don't understand their field of research. And I see no reason to believe that a mining engineer and an economist have any corner on what is accurate.

In biology, there are numerous examples where this wasn’t true...

Example please.

At this point you're trying to reject what is blatantly obvious and are trying to deflect by saying that my responses are less than scientific, as if the normal progression of science weren't scientific.

angech... "Is this good enough Rob?"

You don't understand what Greg is talking about. That is not questioning the reliability of tree ring data. It's how they identify series that demonstrate a temperature signal and separate them from those that do not.

Try reading some of the material that John Mashey posted above about how dendro work is done.

Michael... "It is science 101..."

So, you are arguing that dozens of active PhD level researchers in this field don't even understand "science 101?"

Really?

It is far more likely that the field is complex enough that it is you who doesn't understand the methods, techniques and special circumstances of the research.

This is pure Dunning-Kruger material.

Mondoman... Perhaps what you don't understand here is tree ring series are cross validated. All of the issues that M&M have proposed have been shown to have no impact on conclusions. The data agree with each other. The data agree with other proxies. The data agree with ice core data (which gives very accurate temperature data).

For anyone citing McIntyre as credible, I again point at this key post, ~academic fraud., combined with use of the unsubstantiated Deming claim that never made any sense, given the real history. His essay was pre-published 3 months early by Fred Singer, before it finally appeared in my favorite "dog astrology journal."
McI: any proxy is wrong if it looks like a hockey stick, but an essay by a petroleum geophysicst who has repeatedly written that AGW is a hoax, published via Fred Singer, is credible. Then there's the provenance of the first image... but that's another story.l

The data agree with ice core data (which gives very accurate temperature data).

Sounds about right. It should after the finest, most well taxpayer funded researchers in the world get their firn in the berm and the tree in the lee all lined up and take that to the bank... Calibrating/converging old cathode-ray color tv's was just as scientific in its' implementation toward a clear picture.

Shorter Tim: "It's all a conspiracy!!!"

Can you cite any peer reviewed, scientific studies to show that it is not, Michael Wells??

No? Who would pay for that when it's sooo simple.
==============================

... When anti-GMO activists claim those genes are soooooo dangerous, biologists talk about the denial.

Marco #56, When little Timmy points out that smoking cannabis didn't make him grow tits or chop up his mommy or wreck his car then chemists, biologists, bankers, politicians, tv preachers, and law enforcement talk about the denial, hu? Well, perhaps the ones with monetary incentive do.

Showa Denko reportedly destroyed the GM bacterial stocks after the EMS cases began to emerge [1989].

http://en.wikipedia.org/wiki/Showa_Denko#Tryptophan_contamination

It would seem the evidence got a mercy flush... I guess there won't be any 'studies to show' that particular GMO didn't cause harm ... It's much more prudent to attribute that to faulty filters.

US supplemental L-tryptophan got banned, regardless of source, in 1990 and replaced with football game TV ads for Prozac.

Prozac was first introduced to the US market in January 1988. It took two years for Prozac to gain its 'most prescribed' status.

http://inventors.about.com/library/weekly/aa980225.htm

And risk my monthly checks from Al Gore and the UN? Bite your tongue!

JM - in your post above, you posted a link (apparently to a ClimateAudit site post) that you claimed had something to do with someone's "academic fraud".

I couldn't find anything on the http://www.webcitation.org/6Apedzido link by Steve McIntyre that had anything to do with "academic fraud"; perhaps you posted a different link than you intended?

Wait. Mondoman, did you just ask John Mashey to explain why that climate audit post is academic fraud????????????

Hold on a sec.....

OK, go.

Don't Bogart that nasopharangeal woo, Greg Laden.

GL - Yes, I guess there's some secret writing I'm missing. :)

Have you tried the link yourself? Part of it refers to some guy named "David Deming" who wrote something, but the links are broken. Nothing that I can find about academic fraud in the main post, though, or in any McIntyre sub-posts on that page. Since you seem to be in the know, maybe you could clue me in?

I am familiar with the story, but John has done a lot of work to figure this out, and since he's around, I'll let him tell it, he knows way more than I do about it.

I'm amidst holiday visits & updating a broken computer, but I'll get back to this, I've written about this a few times before, as has Stoat and others, re IPCC(1990) Fig.7.1(c), Lamb(1965), etc.

But for Mondoman and others that might want an exercise in skeptical thinking, Did McIntyre's original 2005 post seem credible> It is actually fairly easy to check.
1)

JM, thanks for your note, no rush -- I'm busy, too! Your most recent link seems to be the same one I asked about above. I did read it fairly closely, and as I mentioned didn't see anything about academic fraud by McIntyre there, so any clarification or other ref would be welcome when you have a chance.

PS - if you're *the* UNIX guru JM, thanks for your contributions to the field!

Rel quick, maybe more later

1) See annotated IPCC(1990), pp.199-203). The curve in Fig.7.1(c) originated with Lamb(1965), via Lamb(1982), and used rainfall and other data to try to estimate the temperatures of Central England. See Adoration of the Lamb.and backtrack into the "flat-Earth map" posts.

Real science tends to surround graphs with explanations and caveats. Some people grab graphs, ignore the surrounding caveats and then write falsehoods about sources, or copy the graphs from somebody else.

2) Deming wrote a (totally-unsupported) story in 2005, that would never stand up in court, claiming something happened in 1995 ... but real scientists were already far beyond thinking the MWP was large, global, synchronous and warmer than 1990. (People certainly thought the MWP was warmer than the LIA, but of course, all that was irrelevant to the existence of modern AGW.)

3) McIntyre claimed it was IPCC(1995) ... which meant he wasn't looking at either (1990) or (1995) ... FALSE CITATION.
In this case, the difference is significant: Deming's story might be barely plausible if this graph:
a) Were in 1995
b) Lacked the caveats around it

4) The image isn't even exactly from IPCC(1990), but in 2012, when questioned, McIntyre said he couldn't recall where he got it. The same image was found in 2001 on website of John Daly, a nonscientist "science advisor" for the Western Fuels Association, ~Wyoming coal. McIntyre and McKitrick used it in several key talks in April/May 2005, it was in the Wall Street Journal in June, and is in The Greatest Hoax(2012), by James Inhofe, p.33.

5) IPCC(1990) and (1995) were only scanned and placed online in 2010 ... Obviously, neither McIntyre nor McKitrick had these in 2005 ... or they deliberately ignored them.

Citing sources you don't have is FALSE CITATION, and doing it in ways that misrepresent them often rises to ACADEMIC FRAUD. This is just the tip of the iceberg ... as there is a very strange story behind the Deming essay, first published at Fred Singer's website, 3 months before it's official publication in my favorite "dog astrology journal."
There are other strange stories around this, but they get complicated.

This one is simple: OBVIOUS FALSE CITATION, needed to support a false narrative. At credible university, things like this support allegations of academic misconduct. For student term papers: F.

John Masley,

re that Lamb chart, the irony sure burns on that one.

The deniers are treating a schematic of unknown provenance in the IPCC report as gospel. I am sure if the boot was on the other foot they would be screaming "chartgate" or something like that.

I still run into people saying that the IPCC buried the MWP when they replaced the HH Lamb graph with MBH98/99. And most recently I had some denialist telling me that even the IPCC thinks MBH is flawed because they didn't include it in AR5, ignoring the fact that that MBH is now 15 year old research.

Part 1 of 2
<a href="Pseudoskeptics are not skeptics.

DAVID DEMING
David Deming, at Wikipedia or DeSmogBlog. Briefly, he is ~petroleum geoscientist (or was, not sure he's published much peer-reviewed work lately), affiliated with think tanks like NCPA, which certainly has gotten ExxonMobil funding See ToC for his Black and White, including "Inhofe Correct on Global Warming," "Global Warming is a Fraud," "Why I Deny Global Warming," etc. I own this book, and the titles are accurate.

His 2005 essay claimed he got an email ~1995 (after June, when his Science article was published):
"A major person working in the area of climate change and global warming sent me an astonishing email that said "We have to get rid of the Medieval Warm Period."

Sadly, he'd thrown away the astonishing email and could not remember the name of the "major person."

Historically, this made zero sense:
1990 IPCC(1990) pp.199-203, annotated including Fig. 7.1(c)). Many people have mis-used that Figure by ignoring the surrounding text (misrepresentation) or never reading it.

1994 Hughes and Diaz(1994) was clear that there was no large global synchronous MWP, although it was generally warmer than later in LIA ... and that simple schematics like in IPCC(1990) should be disregarded.

1995 IPCC has a reconstruction from 1993, Fig 7.1(c) was long gone.

2009 Jones, et al (2009) High-resolution palaeoclimatology of the last millennium: a review of current status and future prospects
Fig 7 on p.34 and Appendix A, p.36 trace the history from Lamb(1965) to Lamb(1982) and onward.

2010 Strange Scholarship in the Wegman Report aligned the IPCC graphs on one page.

Part 2 of 2
CURIOUS PUBLISHING HISTORY OF DEMING(2005)
2005.03.05 Fred Singer, The Week That Was.
Global Warming, the Politicization of Science, and Michael Crichton's "State of Fear"*
*Preprint, to be published in the June, 2005, issue of the
Journal of Scientific Exploration, v.19, no.2 http://www.scientificexploration.org/jse.php
Singer and Deming had been in contact for a while, and Singer almost certainly had seen IPCC(1990), given his Hot Talk, Cold Science (1998 and 1999), p.56, where he took one quote from "IPCC WGI (1990, p.203)", i.e., cited correctly, albeit cherry-picked. Later, in 2007, he and Dennis Avery ascribed the Figure as Figure 22 of IPCC 1995, p.68 of their book, a fabrication amusingly copied in 2 other books.

Singer had also known Ross McKitrick and Christopher Essex no later than Spring 2001, if not earlier.
Singer was in contact with McIntyre by 2003.

2005.06 Essay published at JSE, not online and carried by few libraries. Most articles are now freely available here.
The Journal of Scientific Exploration is A Dog surveys the issue in which Deming's essay finally appeared.
JSE is my favorite "dog astrology journal," far more innovative than mere UFOs, reincarnation, ESP, etc.

TREATMENT BY (PSEUDO)SKEPTICS
100% acceptance of Deming's story as Truth, by Singer, McIntyre, McKitrick, Andrew Montford, Richard Lindzen, James Inhofe and many others. Zero real skeptical thinking.

Deming's tale was crucial to Montford's The Hockey Stick Illusion, but see discussion at Wikipedia.

SUMMARY
Suppose someone heard from a Philip Morris employee claiming to have gotten email years ago from a major medical researcher saying that the claims of cigarette-disease links were a hoax by the medical establishment to assure funding, and so they had hide the truth that somebody's uncle smoked a pack a day and lived till 90, so there really was no problem. Lest this seem a strange parallel, many of the books that include the Deming story involve the same think tanks who have long taken money from tobacco companies...

claiming something happened in 1995

Not Jack Crap happened in 1995 (meteorologically speaking) -- That probably traces back to the 1991Mount Pinatubo eruption which took a few years to squirt its' effects across certain bifurcating boundaries and be considered 'global'.
---------------------------------------------

JSE is my favorite “dog astrology journal,” far more innovative than mere UFOs, reincarnation, ESP, etc.

Well, John Mashy; Maybe nothing happened in 1995 except some stirrings of HAARP and a bunch of Inflammatory Rhretoric... But I think this would make that JSE up to snuff innovative-wise compared to that other stuff you mentioned:
-------------------------

http://en.wikipedia.org/wiki/Schumann_resonances
==================================

Polar view
http://postimg.org/image/8qb49j0cr/

US view
http://postimg.org/image/ft4zaftbn/
=========================

Tropicana Field : 27°46’05.36″N, 82°39’12.33″W
Rick Perry’s Haarp: 27°56’28.80″N, 98°47’50.03″W

Point A : 37°03’03.03″N, 105°08’33.33″W
Point B : 37°55’55.33″N, 76°21’03.33″W

Quake A : 37.05N, 104.66W
Quake B : 37.93N, 77.93W

Gakona haap : 62°23’32.76″N, 145°09’01.47″W
Peru haarp : 11°57’05.33″S, 76°52″27.90″W
China haarp : 40°24’15.91″N, 93°38’9.74″E

Arecibo : 18°20’38.60″N, 66°45’9.88″W
gotta be here : 18°46’23.33″N, 110°55’49.12″W

Minot AFB : 48°24’11.00″N, 101°21’40.97″W

SuperDARNs
þykkvibær : 63.86 N, 19.20 W
Rankin Inlet : 62.82 N, 93.11 W
Kapuskasing : 49.39 N, 82.32 W
Wallops Island : 37.93 N, 75.47 W

Millstone Hill RO : 42°37’3.49″N, 71°29’30.36″W (not official superDARN site)
Blackstone, VA : 37.1 N, 78.0 W
Prince George : 53.98 N, 122.59 W
Saskatoon : 52.16 N, 106.53 W
Goose Bay : 53.32 N, 60.46 W

a Wind Profiler : 28°37’39.15″N, 80°41’42.68″W
a tree farm : 47°44’11.18″N, 79°56’18.46″W
a similar tree farm : 18°34’16.47″N, 68°25’8.36″W
Delano, Ca VOA staion: 35°45’14″N 119°17’6″W
===================================

Yea, I know it all falls apart unless Tropicanna Field is a clandestine HAARP station:

Tropicana Field the night before:
http://youtube.com/watch?v=HWoT6lyIK_g
http://youtube.com/watch?v=XtnKQLcdrH8
-------------------------------------------------------

the sports report on the incident
http://sportsgrid.com/mlb/tropicana-field-is-haunted-by-g-g-g-g-ghooooo…
-------------------------------------------
The quakes of August 22,23 2011
http://en.wikipedia.org/wiki/2011_Virginia_earthquake
http://en.wikipedia.org/wiki/2011_Colorado_earthquake

==========================================

You see? It is all a conspiracy because heating causes expansion and maybe makes a great plausible deniability map for OtH radar corridors.

#84 quick, #87 Part 1, #88 Part 2.
Part 3: Ross McKitrick and Steve McIntyre, through 2005.

MCKITRICK AND ESSEX
McKitrick was certainly connected with Fred Singer and the Washington, DC thinktanks by early 2001.
Essex and McKitrick, Taken by Storm (2008):
‘... in March 2001, Chris was helping organize the Nerenberg Lecture at the University of Western Ontario. That year’s speaker was S. Fred Singer, … we invited the-then federal environment minister, David Anderson’ [p.66, first sentence not in earlier version] That's this talk at U of Western Ontario.
That was later followed by:
(2008) Sallie Baliunas and (2012) Christopher Monckton, as described Wayback here. UWO web pages mentioning Monckton seem to have disappeared. :-)
October 2001, McKitrick spoke for the Cooler Heads Coalition.

Essex and McKitrick(2002) Taken by Storm, on p.169 showed "Borehole-based temperature statistics, AD 1000 to 2000." Graphs are powerful. They mis-used Huang, Pollack and Shen(1997), who by 1998 said 500 years was the limit. SSWR, pp.138-139 has more detailed discussion.
Neither Essex nor McKitrick showed the slightest evidence of borehole expertise, so this could have been merely scholarly incompetence to mis-use an obsolete 1997 source in 2002 and 2005. Other explanations are possible.

MCKITRICK, 04/04/05 (McK05), more detail SSWR p.139.
MCK05 p.4 repeated Deming story ... and even noted that Deming's paper went back 150 years in N. America, totally irrelevant to MWP issues. McKitrick cited it as "Forthcoming, Journal of Scientific Exploration, v.19, no.2." thus obscuring only real location at that time, Fred Singer's website.

McIntyre and McKitrick, 05/11/05, MM05X was the crucial presentation in Washington, very likely the inspiration for Barton letters, and clearly the key resource and "blueprint" for the Wegman Report. There were various version of this, and SSWR was slightly wrong. This one is a PDF of the PPT that Wegman got from Barton Staffer Peter Spencer in 2005, which Wegman gave to Dan Vergano in response to a 2010 FOIA. SSWR pp.27-32 has the chronology.

MM05X p.10 IPCC(1990) Fig 7.1(c), but Daly image (not actual) labeled IPCC 1995. FALSE CITATION = FRAUD.

MM05X p.11 Boreholes, same reference to (obsolete) Huang, et al (1997). INCOMPETENCE OR FRAUD

MM05X p.12 Background: the MWP Problem ...
'D. Deming, Science 1995 With the publication...'
The 2005 quote from SEPP/JSE had now become a 1995 quote from Science. FALSE CITATION = FRAUD ...
But that "error" certainly made the story more plausible. SSWR 136-142 has more detail.

Wall Street Journal, 06/21/05, What Warming? in Kyoto by degrees used same image as Daly/M&M.
'exactly as shown in the 1990 report'
'Dotted line represents mean'
'source: IPCC'
That's 3 X FALSE CITATION = FRAUD

RE: Comment 89.

FYI, there is ZERO reputable evidence for geoengineering being implemented beyond the field trial "proof-of-concept" stage.

Further, chemtrails are nonsense and HAARP is being dismantled.

“There’s nothing remotely secret or even classified about HAARP. No security clearance is needed to visit and tour the site, and HAARP usually holds an open house every summer during which anyone can see everything there. During the rest of the year, research is conducted. There are several other similar research stations around the world, namely the Sura facility in Russia, EISCAT in Norway, the Arecibo observatory in Puerto Rico, and the HIPAS observatory near Fairbanks, operated by UCLA. Sadly for the conspiracy theorists, HAARP has no potential to affect weather. The frequency of energy that HAARP transmits cannot be absorbed by the troposphere or the stratosphere, only by the ionosphere, many kilometers higher than the highest atmospheric weather systems.”

And

"The program is being shut down because its research is done and its funding is spent."

- http://news.discovery.com/earth/weather-extreme-events/target-of-weathe…
- http://contrailscience.com/what-in-the-world-are-they-spraying/
- http://contrailscience.com/how-to-debunk-chemtrails/
- http://contrailscience.com/
- http://earthsky.org/earth/crazy-weather-you-cant-blame-haarp-anymore#.U…
- http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/08/16/…
- http://www.wired.com/politics/security/magazine/17-08/mf_haarp?currentP…
- http://www.davidsuzuki.org/blogs/science-matters/2013/09/conspiracies-f…
- https://www.metabunk.org/threads/debunked-chemtrail-plane-interior-ball…
- https://www.metabunk.org/threads/debunked-pilot-forgets-to-turn-off-che…

"If the chemtrail conspiracy were true, millions of pilots would be needed to crop dust the American population. A typical crop duster might use seven ounces of agent diluted in seven gallons of water to cover one acre of land.

Chemtrail “people dusters” would use a similar concentration to cover the entire United States, just to be safe. For 2.38 billion acres of land, the pilots would then need—for just one week of spraying—120 billion gallons of these cryptic chemicals. That’s around the same volume as is transported in all the world’s oil tankers in one year. And such an incredible amount of agent would need an incredible number of planes.

Considering that a large air freighter like a Boeing 747 can carry around 250,000 pounds of cargo, at the very least, the government would need to schedule four million 747 flights to spread their chemicals each week—eighteen times more flights per day than in the entire US.

Unless a plane could make multiple runs per day, a true chemtrail conspiracy would need 2,700 times as many 747s as have ever been constructed."

- http://www.csicop.org/specialarticles/show/a_million_poisoning_planes

"12) Is there any link between cloud seeding and chemtrails?

No. The WMA is unaware of any connection between cloud seeding as is practiced by its members and to what some refer to as “chemtrails” (chemical trails).

Atmospheric scientists even dispute the existence of “chemtrails”. What some chose to call chemtrails are actually “contrails” (condensed engine exhaust trails), which are well-understood atmospheric phenomena. Contrails are defined as “streaks of condensed water vapor created by an airplane or rocket at high altitudes.” These condensation trails are the result of normal emissions of water vapor, carbon dioxide, and some carbon-containing particulates from piston engines and jet engines at high altitudes in which, given the right atmospheric conditions, the water vapor condenses into a visible cloud.

Actually, due to the very cold temperatures at high altitudes, the water droplets that initially form this cloud rapidly freeze, forming an ice cloud similar to naturally occurring cirrus clouds. Under certain conditions contrails can merge or contribute to the development of a larger area of cirrus clouds. Contrails are normally observed on otherwise clear days, when cloud seeding would not be conducted. The cloud seeding nuclei from ground or airborne sources do not produce such visible clouds."

- http://www.weathermodification.org/faq.php

Physicist David E. Thomas took a closer look at the KSLA report. Thomas notes:

“The actual video clearly shows 68.8 ug/L (micrograms per liter), or 68.8 ppb (parts per billion)…. 68.8 millionths of a gram per liter corresponds to 68.8 parts per billion, (and) the reporter was off by a factor of 100 because he read the ’68.8′ as ’6.8.’ Ferrell overestimated the amount of barium in the test report by a factor of 100…. The test result was not ‘three times the toxic level set by the EPA’; it was around 30 times less than the EPA’s toxic limit.”

So the alarming levels of barium that noted conspiracy theorist Jim Marrs cited as evidence of chemtrails was in fact a mistake created by a TV reporter’s poor math skills.

- http://news.discovery.com/human/psychology/viral-video-claims-to-prove-…

Note the Burden-of-Proof is on the claimant (you) to support it. Also note that conspiracy blogs, YouTube videos, pictures of the sky and newspaper articles are not credible.

"The burden of proof lies with someone who is making a claim, and is not upon anyone else to disprove. The inability, or disinclination, to disprove a claim does not render that claim valid, nor give it any credence whatsoever."

- https://yourlogicalfallacyis.com/burden-of-proof

Dozens of wingnuts have been confronted with this challenge. All have failed.

And so will you.

Atmospheric scientists even dispute the existence of “chemtrails”

Well, Daniel Bailey; Don't tell that to those atmospheric scientists who get grants to study the feasability of spraying *shiny stuff* into the atmosphere to 'combat' AGW.

I'd also not mention it to those who may study the feasability of flying into hurricanes and seeding key parts to initiate precipitation/deep convection outside the eyewall in an attempt starve it; Causing a loosening of the eye and consequent reduction of maximum windspeed there -- If I were to hazzard a guess, some of them might even be employed under the table by insurance companies to do so. <-- That would probably be dodgy to do (if doable) particularly if doing so limits maximum windspeed and damage to expensive and insured buildings in a narrow strip while trading off for more precip over a broader area. Really, who bothers with flood insurance anymore??

Just water vapor? I did not know that, thx. But I do seem to recall a couple of occasions where the warm, spring air on a lovely sunny day was filled with what appeared to be spider webs; Being young then, I first took them to be webs myself, as that does happen -- But then there was the local weatherman on television explaining that Charlotte's childrens' webs flying and sticking all over town were not only not webs nor chaff but were, in fact, "residue from a new jetfuel additive."

Harummph. Next you'll be telling me that these beautiful punchhole clouds aren't really giant vacuum-as-lifting-gas, invisible spyblimps but are really UFOs":

http://www.darkroastedblend.com/2008/12/punch-hole-clouds.html

Or that those *rings* around the NEXRADs aren't for weather control but are the result of the tilted beam scattering back information from a greater elevation the farther the range thus revealing the abrupt refractive index change as the 'height' of the local boundary layer, or depth of a swarm of insects, or the lower extent of snowfall or virga:

https://www.youtube.com/watch?v=1k7SLlshOas

Or that this is not the result of when the Fat Lady sings on Independance Day:

http://www.erh.noaa.gov/iln/research/birds/
-------------------------------------------

Unless a plane could make multiple runs per day, a true chemtrail conspiracy would need 2,700 times as many 747s as have ever been constructed

Wow. Somebody's thinking kinda big, don't you think? Surely individual segments or a local populace can (and have) been 'dusted' -- Sometimes, just for giggles to see if they jump out of windows or get sick.

Surely, the volume/mass/particle count would depend on what is being sprayed. Don't climate scientists 'trace' the sources of CO2 based on itsy bitsy amounts and ratios of isotopes of carbon, oxygen, and the like?? Haven't injected (by old bomb tests, mostly) radioisotoptes of nitrogen been used to map out changes in the stratosphere? I'd bet, relatively speaking, that gobs of that stuff might fit into a small plane...

But, If I were to speculate (and I like to speculate) what types of small, lightweight *stuff* might get sprayed out of a plane then I might dwell on nanospydust; Perhaps like tiny taggants or RFID -- An array of myriads of little Theremin's Things blanketing a landscape to, idk, be energized by some supersecret satellite beams in some band or other and modulate the backscatter to some aspect of their surrounding environment (such as sound). Hmm??

http://en.wikipedia.org/wiki/The_Thing_%28listening_device%29#Operating…
------------------------------------

The frequency of energy that HAARP transmits cannot be absorbed by the troposphere or the stratosphere, only by the ionosphere, many kilometers higher than the highest atmospheric weather systems.

Ohh, I agree completely. But, as I understand it, the HAARP enery is amplified by causing a sort of 'cascade' of stacked ions up there. Indeed, "heating causes expansion" was the rallying cry, early on -- To *heat* portions of the ionosphere and make it expand and lift into the path of boost-phasing missiles.

Now, what goes up past equillibrium will fall below equilbrium upon rebound -- A so-called *buoyancy wave* that 'may' possibly have an effect on the lower strata. Either way, an oscillating ionosphere constitutes an electric current though I can't figure out what good that would do anybody -- maybe something to do with the lithosphere.

http://www.physics.uwo.ca/~whocking/p103/grav_wav.html

I must concede that I've offered no 'proof' of anything here. You must concede that being allowed to visit Gakona does not mean the program is 'shut down'. After all, one may also tour the Delano, CA VOA station yet propaganda still thrives.

http://www.w6lie.org/voa1.htm
===================================
p.s. Who said anything about 'chemtrails'?

Perhaps the anonymous "Tim" will explain to us why
#89 had anything to do with this post or the discussion here.
Was that just interjection of a favorite conspiracy theory or a desire to distract from documentation of academic fraud in response to Mondoman's questions?

You caught me, John Mashey. I interject because ya'll use lots of words and words and 'studies to show' and 'no studies to show' when the truth is, at the end of the *day*, the correct answer is whatever fits the predestined agenda and course...

I *was* attempting to hijack this thread with something interesting to me because ya'll spending grant money to study a camel pissing away it's hump to malign CO2 gets rather stale.

It just seems to amount to poorly-understood feedback mechanisms and conjecture 'angels on a pinhead' miniscule over the justification for futher global governance enslavement. Of course, YMMV. I apologize that yours (and #91's) was tl;dr.

Tim... Have you ever actually read any of the published research?

While tipping points for feedbacks are not well understood, it is very well understood that they're out there and generally how they operate. Scientists look very hard and all these issues in order to constrain the uncertainties. That's why the research shows that the most likely climate sensitivity is ~3C for doubling CO2. It might be a little bit lower. It might be a little bit higher. But there is some possibility it is a lot higher (but that is still a low probability).

One cannot reason with those whom abjure its use. Typical of the ilk.

Tim is just haarping about, er, I mean conscientiously warning us about the most monstrously conceived and dangerous communist plots we have ever had to face.

You see, he can no longer sit back and allow Communist infiltration, Communist indoctrination, Communist subversion and the international Communist conspiracy to sap and impurify all of our precious bodily fluids…

Nanospydust, Mandrake! In children's ice cream! Do you know when this began? 1984. Nine-teen hundred and eighty-four.

Now be sure to burn your PC after reading this, but be very careful not to breath the fumes... They'll cause chemtrails, cascade stacked ions in your brain, and allow those communist supersecret satellite beams to modulate the backscatter as the refractive index oscillates out of equilibrium.

This is just another way of introducing foreign substances into our precious bodily fluids without the knowledge of the individual, and certainly without any choice. That’s the way your hard-core Commie works...

Be sure that you only drink pure rain water and grain alcohol.

Naa, Rob Honeycutt -- I tried them on audiobook but couldn't get past the part where they killed that dude with the tiny poison octopus....

Some of those *tipping points* do sound pretty ominous. It would seem that no matter what clathrate happens from time to time and then ... Perhaps someone should tax Earth out of its' impetus to cycle limestone.

When all is said and done, I still don't foresee anyone being allowed a tax credit or a reduction of community cohersion for not mowing their lawns.

#96 DB
Yes. For some of us, online bulletin boards go back ~30 years, and one quickly learns to assess commenters. Sadly, blogs don't have as reliable a mechanism as USENET KILLFILEs for ignoring people forever;

The blogosphere is like Eternal September on steroids.

Communist subversion and the international Communist conspiracy to sap and impurify all of our precious bodily fluids

Aaah, when I was an undergraduate math/physics major in the 1970s there was this one young woman, a year ahead of me in math, who claimed to be a communist. I don't know that she impurified my bodily fluids but a goodly amount did suffer the other fate.

Good times, good times.

Dean, you mean you didn't "deny her your essence"?

"you mean you didn’t “deny her your essence”?"

I did not. What can I say: I was young and impressionable, she was intelligent, witty, didn't take crap from anyone, hot - and differential equations and linear operators were just so damn hot.

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