I had a brief email exchange with Professor
Dear James,
This is fascinating. I had no idea these emails were in the public domain.
In general Steve has gotten most of this right. There really is a problem
with the trees not being sensitive to temperature after about 1950. My
current best guess is that the higher CO2 since then has caused greater
warming at night (which is corroborated by minimum temperature trends,
since minimum temperatures usually occur at night). Trees respire more
at higher temperature, so they lose carbon when nights are warmer
than average. So their ring width has not increased as much as it would
have if the warming had been uniformly distributed over the diurnal cycle.
I think this is all published now so it should be possible to set the whole
record straight. But I did indeed feel at the time that Mike Mann had not
given me a straight answer. So if there is a response written, it won’t be
one defending Mike.
Jeff
Cheers,
James Padgett
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James:
Nicely done. If Severinghaus is correct, then there is yet another major complexity in tree rings as thermometers. It sounds like there are other players to be heard from on this.
Then allow me to put emphasis where it belongs….. “But I did indeed feel at the time that Mike Mann had not given me a straight answer. So if there is a response written, it won’t be one defending Mike.”
Of course what often gets lost in these dendro discussions is the fact that temperature reconstructions using tree rings is akin to phrenology. But, even if it wasn’t, how many years did we have local temps in the areas by the trees? Not very damned many.
So, for an ~ 200 year history, we’re throwing out more than half of the years, because they don’t match the actual temps, but they say they match actual temps…..lol.
The pinheads, through statistical acrobatics, found a brief window of time where the numbers almost correlated. Then drew their sticks from that.
Students/post docs routinely do studies on (local) living trees on a daily basis. It’s likely that they have very detailed data on correlation with meteorological data, temps, precip, humidity and what have you, upto this year. They should publish some of that.
Obviously it is assumed that the best place to register temperature data in treerings is where temperature is considered the most limiting factor, i.e. close to the arctic or mountain treelines. However if trees react to carbon fertilization, those trends should be visible in those contemporary studies of local trees. Is there a ‘decline’, students?
Overriding this all though is still the assumption that trees would be a good proxy for temperature if it wasn’t the obfuscating action of increased heat from CO2.
The recent post containing a letter from John Daly listed no fewer than 6 completely valid other factors affecting tree ring width, meaning it will NEVER be possible to separate a temperature signal from the noise. Trees should just be forgotten about and more reliable proxies found.
Severinghaus best guess is warmer nights make the tree grow more slowly? Okay – my best guess is increased atmospheric CO2 might increase the growth rings because there is lots of empirical evidence trees grow faster (ie fatter growth rings) in a CO2 enriched atmosphere.
I know the point is: Mann was evasive. …but trees not being sensitive to temperature after 1950 is a lame excuse for stinky data.
The partial list of state variables that effect tree ring growth from John Daly:
sunlight – if the sun varies, the ring will vary.
cloudiness – more clouds, less sun, less ring.
pests/disease – a caterpillar or locust plague will reduce photosynthesis
access to sunlight – competition within a forest can disadvantage or advantage some trees.
moisture/rainfall – a key variable. Trees do not prosper in a drought even if there’s a heat wave.
snow packing in spring around the base of the trees retards growth temperature
Growth will be nonlinear in all/nearly all of these variables. In fact, some of these affects would result in discontinuities rather than just a change in growth rate (e.g. pests). Even if we knew what the nature of these nonlinear responses were we could not solve this “problem” without knowledge about initial conditions for all state variables. That is, we would need knowledge about all of the variables, at sufficient resolution and accuracy, for the last 1000+ years. And we would need this information on a spatial scale that allowed us to address the individual advantaged tree. It’s absurd.
With regard to the explanation that warmer temperatures at night meaning trees respire more and lose carbon …
If false it fails as an explanation of `divergence’.
If true it explains divergence by completely invalidating the use of tree rings as a temperature proxy. The assumption is that the response to warming is greater growth, not less.
USA Today:
http://content.usatoday.com/communities/sciencefair/post/2011/11/public-learning-scientists-agree-on-climate-a-game-changer/1
But it’s not true!
WTF?
Wouldn’t the logical conclusion be “these particular tree rings are a poor temperature proxy” if the most recent data (which one would expect to be the highest quality of the set) showed an inverse relationship?
What incredible twisted logic on lack of nighttime cooling And its effect on tree ring growth — has anyone else postulated this, or was he imbibing in the nectar of the vine (or perhaps one bong too many)?
Kurt in Switzerland
After 1950 we have thermometers. In fact, after 1750 we have steady records from a few carefully maintained thermometers. We shouldn’t even be discussing other measurements for years when we have thermometers, and we shouldn’t even be trying to average or mix temperatures in different places.
Remember junior-high science class? The teacher puts one hand in cold water and the other hand in hot water. He says “My left hand is at 100 degrees, and my right hand is at 40 degrees. Thus my Average Hand is at 70 degrees, which is perfectly comfortable!” The more alert students understand the fallacy immediately. None of these so-called “scientists” were alert students.
So, on Mann’s and the teams trees.
Is it possible the trees are working true with “Origin of Species” as they do not know the path set for them by the team.
Time , tide, and trees too await evolution not hockey stick graphs.
Professor Severinghaus believes that there is empirical work that will withstand scrutiny and that explains “the decline” in tree rings. I cannot wait to see this. I just cannot wait. If it exists, it will be the first empirical work done by The Team.
Anthony, why did you not post the links that the professor provided to this empirical work? /sarc
> so they lose carbon when nights are warmer than average.
This is a hypothesis that can be verified by experimentation. It wouldn’t even take that long to test it and it would make a change for dendroclimatologists to perform an actual experiment rather than playing with stats packages.
Theo Goodwin says:
November 28, 2011 at 2:02 pm
Professor Severinghaus believes that there is empirical work that will withstand scrutiny and that explains “the decline” in tree rings. I cannot wait to see this. I just cannot wait. If it exists, it will be the first empirical work done by The Team.
Anthony, why did you not post the links that the professor provided to this empirical work? /sarc
=====================================================
It’ll probably be published just as soon as the empirical work about the missing heat at the bottom of the ocean is published.
This opens up another front – one senses a rather cold front for the Team. Well done James, thanks Professor Severinghaus.
Dr. Severinghaus points out one mechanism that might cause trees to fail as a proxy for temperature and implies there may be others.
For me, this begs the question of what mechanisms may have invalidated the proxies used to disappear the Medieval Warming Period.
I found the concern about warming mind boggling in the 1990s because we are inevitably heading into another ice age.
I found the divergence problem mind boggling in the 2000s because it means the proxies cannot detect prior warming periods.
I know correlation is not causation but surely divergence is another matter. As a scientist, I would have taken divergence as an indication that the pre-divergence correlation is indeed not causation.
So the decline is CO2 fault also. CO2 is causes everything except good things. Now I ‘ve got it.
Severinghaus’s current best guess — that warmer nights mean that trees respire more CO2, hence have less carbon to add to tree rings — is quite interesting.
But, since the Medieval Warm Period (MWP) has now been restored, including in the Kobashi et al 2009 paper of which Severinghaus was a co-author, then I would have imagined that the same effect of warmer nights and thus smaller tree rings would have been observed back then. But it doesn’t seem to be that way. Is there a reason why CO2-caused warmth increases (today) would cause nightime temps to be higher, while non-CO2 increased warmth (the MWP) would not cause nighttime temps to be as high as with CO2-induced warmth? I can’t think of a reason.
I may be missing something, but if I’m not, then the warmer nights hypothesis for smaller growth in tree rings doesn’t seem quite right.
The other thing is that CO2 is a fertilizer. The Idsos and many other researchers have shown time and again that plants grow more quickly with more CO2. Tropical trees and temperate trees add more carbon lately, in our now higher CO2 environment, we’ve seen in a number of studies. So if the trees add more carbon, why would tree rings show less growth? In theory, the added carbon could be more in roots than above ground, but I know of no reason why that would be, at least not yet.
Cross-posted from Climate Audit:
Excerpt from 0237, Tim Osborn, March 2006:
“I have co-authored a paper in Nature on the reduced response to
warming as seen in tree-ring densitometric data at high-latitude
sites around the Northern Hemisphere, increasingly apparent in the
last 30 years or so.
First, it is important to note that the phenomena is complicated
because it is not clearly identifiable as a ubiquitous problem.
Rather it is a mix of possible regionally distinct indications, a
possible mix of phenomena that is almost certainly in part due to the
methodological aspects of the way tree-ring series are produced. This
applies to my own work, but also very likely to other work.
The implications at this stage for the ‘hockey stick’ and other
reconstructions are not great. That is because virtually all long
tree-ring reconstructions that contribute to the various
reconstructions, are NOT affected by this. Most show good coherence
with temperature at local levels in recent decades. This is not true
for one series (based on the density data). As these are our data, I
am able to say that initial unpublished work will show that the
“problem” can be mitigated with the use of new, and again
unpublished, chronology construction methods.”
If I am interpreting this correctly, Osborn is saying that the “divergence problem” with the hockey stick arose primarily from “methodological aspects,” and had little or nothing to do with actual tree rings. I, and many others I’m sure, have suspected this ever since MM03.
Hold on for a second.
Let’s accept, for the sake of argument, that when you measure the trees rings of trees situated in extreme locations, there is a high degree of correlation between the ring growth and temperature with one exception: if the temperatures are very high, as they are now, there is some, as yet not fully explained reason why the growth is lower than one might otherwise expect.
That assumption would fully explain the current situation—temps are up but tree ring growth is modest.
So now lets look at the dendro chronological record over the last couple thousand years to see if there are any extreme temperatures. How do we find them? Not by looking for the very highest ring growth but by looking for modest growth. And look, there are lots of examples. To be sure, most of the examples of modest growth correspond to modest temps, but we’ve just established that extreme temps are associated with modest ring growth, so we can’t look at the ring growth record and conclude there are no extremely warm temps, we just don’t know.
The ring scientists want us to believe that record high temps are associated with record high growth, and since there is no record high growth there must be no record high temps in the past.
Yet we’ve established, with 30 years of empirical evidence, that record high temps are associated with modest ring growth, so one cannot use the ring growth to exclude high temps in the past.
Daft question; has anyone else tried to re-create Manns work? Perhaps not the HS 1000 years, but what about say, the 20th century? How accurate or otherwise would other tree rings be in replicating known temparatures?
Here is a e-mail from FOIA that sheds some light on the subject:
http://foia2011.org/index.php?id=647
A letter regarding IPCC revisions, dated 9/23/99
My main concern here is with a reference by Mann writing that Briffa’s tree ring series shows a decline, a decline in temperature, using Briffa’s tree ring series for the MBH99(hockeystick)
Mann,
“Clearly there is one overiding thing to make sure of here: that
we have the right version of your series. I *think* that we do.”
(talking about Keith’s tree ring series.)
Later Mann writes:
“This directory has all the series, aligned as I described to have
a 1961-90 base climatology (or in the case of your series, a pseudo
1961-90 base climatology achieved by actually matching the mean of your
series and the instrumental record over the interval 1931-60 interval).”
(The directory no longer exists, but whats inferred here Briffa’s tree ring series is pseudo?)
Briffa replies, in regards to the robustness of the MBH99 series.
“Mike , I agree very much with the above sentiment. My concern was motivated by the possibility of expressing an impression of more concensus than might actually exist . I suppose the earlier talk implying that we should not muddy the waters’ by including contradictory evidence worried me . IPCC is supposed to represent concensus but also areas of uncertainty in the evidence. Of course where there are good reasons for the differences in series ( such as different seasonal responses or geographic bias) it is equally important not to overstress the discrepancies or suggest contradiction where it does not exist.”
Is Briffa here stating that ‘we’ shouldn’t include contradictory evidence in the IPCC report?
He later says the IPCC is suppose to represent consensus.
Basically, the ‘we’ decided what was put in the IPCC and not the IPCC reporting the findings they received.
Essentially making the IPCC a puppet of the “The Team”
Here it gets a little dicey. I believe the next quote was actually a copied response by Briffa on something Mann had previously written, or so it seems.
Mann,
“I am perfectly amenable to keeping Keith’s series in the plot, and can ask Ian Macadam (Chris?) to add it to the plot he has been preparing (nobody liked my own color/plotting conventions so I’ve given up doing this myself). The key thing is making sure the series are vertically aligned in a reasonable way. I had been using the entire 20th century, but in the case of Keith’s, we need to align the first half of the 20th century w/ the corresponding mean values of the other series, due to the late 20th century decline.”
Taking what they like and leaving the rest.
If they didn’t like the result, the “team’ just spliced in whatever data they wanted to produce the desired result.
The tone I am picking up in this e-mail, is Briffa’s concern of being left out in the cold (pun intended).
Later Mann is saying that there are discrepancies between Phil Jones’ series and Mann’s series with Briffa’s data included.
Mann,
“But that explanation certainly can’t rectify why Keith’s series, which has similar seasonality *and* latitudinal emphasis to Phil’s series, differs in large part in exactly the opposite direction that Phil’s does from ours. This is the problem we all picked up on (everyone in the room at IPCC was in agreement that this was a problem and a potential distraction/detraction from the reasonably concensus viewpoint we’d like to show w/ the Jones et al and Mann et al series.”
The ‘everyone’ in the room at IPCC said that the 2 series of graphs was a ‘potential distraction/detraction’ from Jones et al, because Briffa’s series showed a decline. That is what is inferred here.
Then this next quote is direct collusion on Mann’s part, regarding the difference between the 2 series.
Mann says,
“We would need to put in a few words in this regard. Otherwise, the skeptics have an field day casting doubt on our ability to understand the factors that influence these estimates and, thus, can undermine faith in the paleoestimates.”
Collusion, manipulation, fabrication, and omission is fraught in this one e-mail alone.
Simply amazing.
One other pattern I find is how both Mann and Jones will come out with guns blazing when some “insignificant” person starts snooping around. If someone starts asking pesky questions, their “supervisor” and/or others at their institution are contacted, often with insulting/condescending context. Interesting. They seem to devote quite a lot of firepower to these “insignificant” pesky ones who ask questions. It is as if a hot ember has popped out of the fireplace onto the rug and they hit building halon fire suppression system to make sure the questions not only stop, but the questioner is possibly properly chastised for having the “nerve” to ask them in the first place.
Insults the student, insults the PhD, insults Berkeley for even considering such a PhD. Amazing. Jones comes off with what we call in the American vernacular a little “prickishness”. There is a subtle psych play here. By insulting the institution, Jones is filling Wehner with a bunch of “oh, my God, someone is making Berkeley look bad!” sort of angst and is basically insuring that the student gets a thorough looking into.
I would think an esteemed scientist would be above that sort of thing.