Discovering a missing piece of recent climate data
University of Vermont
Schoolchildren know that the age of a tree can be measured by counting the number of rings in a stump. But rings in especially old trees contain data that can’t be measured so easily. For example, stands of old growth forest contain centuries worth of temperature data that can be a key to completing the picture of how the climate has changed over the past several centuries.
Shelly Rayback of UVM’s geography department, and two colleagues, Grant Harley of the University of Idaho and Justin Maxwell of Indiana University, are using a $360,000 National Science Foundation grant to unlock this data and reconstruct summer air temperature in the Eastern United States.
“Our colleagues have been able to reconstruct moisture availability in this region, but no one has been able to reconstruct temperature on a large scale across the eastern United States,” Rayback says. “This has been a thorn in our side, because while we have fairly dependable temperature data recorded over the past 120 years or so, we don’t have a clear picture of what the temperature has been like over the past 300-500 years.”
The team of researchers will use blue light intensity methods applied to tree ring samples of several temperature-sensitive tree species from North Carolina to maritime Eastern Canada, like the red spruce. A simple flatbed scanner can extract the blue light data to create a deeper paleolithic temperature record.
“We know average temperatures are rising, but what we’re trying to answer, in a longer-term context is, are the temperatures we’re experiencing today somewhat higher than the past, or a lot higher than the past? We’re guessing the latter is true, but we need the data to support that hypothesis.”
Rayback says the data will be relevant not only to understanding temperature trends in the Northeast, but can also contribute to our understanding of broader climatic trends in the Northern Hemisphere. The data could also contribute to developing better general circulation models (GCMS) that scientists use to predict climate in the future.
Grant Harley is assistant professor of geography at the University of Idaho. Justin Maxwell is associate professor of geography at Indiana University. Rayback is associate professor of geography at UVM.
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“We know average temperatures are rising, but what we’re trying to answer, in a longer-term context is, are the temperatures we’re experiencing today somewhat higher than the past, or a lot higher than the past? We’re guessing the latter is true, but we need the data to support that hypothesis.”
Is there no other options to explore? Perhaps today’s temperatures are somewhat cooler than at some time in the past? Looks like they’re trying to prove only that it’s warmer now.
Looking at temperature over the last 300-500 years keeps it within the Little Ice Age period. Expecting to find colder temperatures than currently is what they expect to find – as one would within the LIA.
“We know average temperatures are rising, but what we’re trying to answer, in a longer-term context is, are the temperatures we’re experiencing today somewhat higher than the past, or a lot higher than the past?”j
Hmm… what about the possibility our current temperatures are LOWER than the past?
Seems they know the answer in advance and just need to dig up some data so support the agreed answer
Let’s see if they can figure out that trees not only stop growing when it’s too cold….they stop when it’s too hot
“blue light intensity methods applied to tree ring samples” — wha?
Googling…
Well, it’s apparently a real thing, in the dendroclimatology community. They attempt to deduce climate information from the color variations of extracts taken from of the rings.
One of the abstracts begins, “Blue intensity (BI) has the potential to provide information on past summer temperatures of a similar quality to maximum latewood density (MXD)…”
That doesn’t sound like a ringing endorsement to me. But maybe by dendroclimatological standards it is.
Michael Mann redux.
I got as far as “For example, stands of old growth forest contain centuries worth of temperature data” and switched off with a yawn. No other factors affect tree ring growth, it seems.
Then I thought, “oh well, may as well read the rest in case it gets any better”. I got to ““We know average temperatures are rising, but what we’re trying to answer, in a longer-term context is, are the temperatures we’re experiencing today somewhat higher than the past, or a lot higher than the past? We’re guessing the latter is true” Oh dear! Only two possibilities and both excluding the possibility of temperatures even staying the same, leave alone falling. Furthermore, a clearly stated incentive to find data to support the preferred hypothesis.
What a waste of time. Do they get paid for this?
“We know average temperatures are rising, but what we’re trying to answer, in a longer-term context is, are the temperatures we’re experiencing today somewhat higher than the past, or a lot higher than the past? We’re guessing the latter is true”
A proper answer to that questions by a scientist is “We don’t know.”
There evidence that these trees are responding to temperature and only temperature is …?
It will be fascinating to see how they control for the spread of earthworms and humans over this exact period.
All of you previous commenters have missed a key point. If their hypothesis proves true, they will in fact be proving that significant global warming occurs WITHOUT a related linkage to increasing CO2 levels, as the era they are exploring is before the widespread adoption of fossil fuels at today’s scale. Thus they will be proving that atmospheric CO2 concentrations are not necessarily the dominant factor behind the climate change (such as it is) that we are experiencing today. Ipso facto perhaps anthropogenic contributions are not nearly as significant as the alarmist’s want everyone to think.
My 2 cents anyway.
From the article: “This has been a thorn in our side, because while we have fairly dependable temperature data recorded over the past 120 years or so, we don’t have a clear picture of what the temperature has been like over the past 300-500 years.”
All we need is the past 120 years of temperature data. That data shows it was just as warm in the 1930’s as it is today, and that means that CO2 is not an issue today because it wasn’t an issue in the 1930’s, so CO2 is not a problem and CAGW (Catastrophic Anthropogenic Global Warming) is dead as a result.
Whatever warmed things up in the 1930’s (Mother Nature) could be the same thing warming things up today. The IPCC says CO2 was not a significant factor in the 1930’s warming, so CO2 does not have to be a significant factor in today’s warming, either, because both warmings are of equal magnitude and reached similar high temperautures. In the United States, it was actually warmer in the 1930’s, than today, by a lot. According to Hansen, 1934 was 0.5C warmer than 1998, and that makes it 0.4C warmer than 2016, the so-called “hottest year evah!”.
The onus is on the alarmists to prove there is a difference between the 1930’s warmth and today’s warmth.
But the alamist’s don’t argue about comparisons between the 1930’s and today, because admitting the 1930’s were as warm as today destroys their CAGW argument. instead they create false realities (Hockey Stick charts) where the 1930’s warmth disappears into insigificance, and then they don’t have to explain the 1930’s warmth away. Convenient for them, isn’t it.
But the alarmists didn’t erase the actual temperature records, they just used computers to change the temperature profile, and then claim they know the temperatures better than the people who actually wrote the temperatures down on paper. But we can see how it was changed to conform to the CAGW fearmongering about CO2. Their bastardization of the temperature record is obvious.
The Data Manipulators should be held accountable. They have inflicted untold harm on the human population of Earth with their lies and distortions of the truth.
Tree ring growth is more dependent on rainfall than temperature. Ask any arborist. Pond bottom pollen is subject to even more variation. There is a bias to “cold location ring samples” where tree trunks are preserved, over warm areas where old trunks rot away, also recent samples over ancient samples, because only “location lucky” trees actually get old. We only “sorta know” these proxy temperatures within a 3 degree C range, not good enough to determine whether a degree over a century, as we have experienced, is unusual or not. The divergence problem between Briffa and Mann data is notable in this regard. Basically one is led to the conclusion that tree ring temperature reconstructions are not very reliable, but very sciency-sounding.
I completed 30 years of atmospheric measurements on 4 Feb 2020. While processing these data will require considerable time. thus far I’ve not found any correlation of temperature with the clearly visible annual growth rings in branches of nearby baldcypress, hackberry and beau d’arc. The rings are slightly correlated with precipitation, but even these data are suspect due to the influence of shade from overhead branches.
The wonderful thing about tree rings is that they can be used either as thermometers or as rain gauges according to taste.
When I was first instructed on how a research effort should be conducted – and a report written – the place to start was with a review of literature. I don’t see that effort here.
There is much that has been written about using “treemometers” for reconstruction of past climate – none of it good.
What a waste of money, time, and educated folk’s brains.
“treemometers”
Jeff Id, I think, but if not, apology to he/she that coined this.
From the UVM associate geography professor, Shelly Rayback, faculty page:
But, but the forests are growing rapidly amid all this pollution!
What could possibly be the cause? We must investigate!
Also take a gander at some of the courses she teaches…
https://www.uvm.edu/cas/geography/profiles/shelly-rayback
we need the data to support that hypothesis.”
Not to test it?
I believe there are old growth individuals in most areas that once had ancient trees. For whatever reason (hollows, low branching, etc.) they were passed up by loggers.
Nonetheless, I don’t know of ANY species that one could look at rings, and say, “That was from lack of water”, or “that was from lack of warmth”.
I do know it is common to look at the growth rings of very old trees (in the Midwest USA that’s 300 plus) and see growth patterns. One that is very common, is to see the first 80-100 years with practically no growth at all. Then it “blossoms”. One always assumes that this is because the larger trees around it were blown up, blown down, or succumbed to some natural event.
I have NEVER seen a competent arborist say they think it’s because the climate changed.
I believe it’s fundamentally bad science from the git-go.
Why don’t they just ask the Idso’s and save themselves a trip?
Link
[QUOTE FROM ARTICLE]”For example, stands of old growth forest contain centuries worth of temperature data that can be a key to completing the picture of how the climate has changed over the past several centuries.”
Tree rings only contain data regarding the growth rate of the individual tree over past years, that doesn’t necessarily correlate only with temperature.
It is possible that an unusually mild early spring and/or autumn may prolong the growing season enough to result in above-average annual growth and a wide tree ring for that year. But what about growth rates during the summer months (June to September) when there is no danger of frost, but growth rates depend more on availability of water (precipitation) than temperature?
During a long period of summer drought, some trees will go dormant, to the extent of dropping some of their leaves in August after a dry summer, while the same trees would grow faster during a wet summer. In general, summer temperatures are higher in sunny weather than in rainy weather, so that a hot summer may actually have slower tree growth (if there is not enough precipitation) than a cooler, wet summer.
A tree ring basically shows the total growth of the tree during the year, an integrated average of the growth rate between when the leaves emerge in spring and when they drop off in autumn. Above average temperatures in early spring or autumn may prolong the growing season, but may slow down the tree’s growth during the summer if not accompanied by enough precipitation, so that tree rings are not a proxy for temperature, but are an indicator of a mix of temperature and precipitation in unknown proportions.
Tree rings of deciduous trees also do not indicate anything about winter temperatures, since such a tree remains dormant from late November through early March regardless of whether there are thaws or cold snaps during the winter.
A detailed study of rings of old trees can answer the question: was the spring/summer/autumn climate of X years ago in this location favorable to the growth of this species of tree? It cannot make any conclusions about temperature.
Another confirmation bias request for money to prove what we know. That is the fundamental problem that plagues politics and political science.
Besides for my previous comment above, I am wondering about what data sets they will use to confirm or correlate temps over the past hundred to 140 years?
Will they use the adjust records published for public consumption, or are they gonna use the original raw temperature data?
If they do not like the story told by thermometers, they simply change what was written down over the years by the people reading the thermometers at the time and in the particular place in question.
So now tree rings are thermometers?
They do not even know how to be honest or stick to scientific methodology.
Mickey Mann will be delighted that the “science” of dendrobfuscation has been picked up by the younger generation. No doubt he can train them how to extract the 365 and 1/4 days worth of hourly records of moisture, temperature, soil nutrients and sunlight that each ring contains to give an accurate average annual temperature.