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Reader Comments (26)
My predictions -
Either:
1 - the temperature reconstruction shows no MWP, or
2 - the MWP blip exists, but is 'adjusted away', or
3 - Dr Rob Wilson will shortly not be lecturing at St Andrews University any more...
I would certainly be interested to know how many appropriate trees of that age still exist in the UK, wholly untouched by human influences, and how they were identified and validated as such.
University of Pennsylvania researchers studied leaf temperatures and found that trees are able to maintain their leaves at around 21 deg C regardless of ambient temperatures.
They concluded this would cause problems for anyone attempting to use tree rings as proxies for temperature as there is no correlation between ambient temperature and tree ring growth.
reported in Daily telegraph in 2008
http://www.telegraph.co.uk/news/science/science-news/3344206/All-tree-leaves-have-thermostat-that-maintains-temperature.html
Extracts from that article below:
“The temperature inside a healthy tree leaf is affected much less by outside temperature than originally believed, from England to the Caribbean, according to biologists at the University of Pennsylvania.
Surveying 39 tree species ranging in location from subtropical to northerly climates, researchers found a nearly constant temperature in tree leaves.
The conversion of light into chemical energy – photosynthesis – most likely occurs when leaf temperatures are about 21°C, and the outside temperature plays little, if any, role. This means that in colder climates leaf temperatures are elevated and in warmer climates tree leaves cool to keep the temperature just right.
The research contradicts the longstanding assumption that temperature in a healthy leaf are coupled to ambient air conditions. For decades, scientists studying climate change have measured the oxygen isotope ratio in tree-ring cellulose to determine the ambient temperature and relative humidity of past climates.
This new work challenges the potential to reconstruct climate through tree-ring isotope analysis, since it suggests the method does not provide direct information about past climate, providing misleadingly warm estimates.”
A comment I made over at WUWT on Willis's article "Aproxymations" a couple of days ago after discussing the many variables affecting tree growth and what appears to be the ability of trees to very carefully regulate their rates of photosynthesis and thus growth despite varying levels of sunlight, water, CO2 and temperature was :
" All in all I tend to think of ‘dendrochronology’ as more of an aspirational art form than science; creative thinking is the order of the day in the absence of any knowledge on what were the key determinants of rates of tree growth at the time the sample comes from – rainfall, sunlight and cloud cover etc. In the light of trees ability to regulate the temperature of their leaves then the temperature appears to have a minimal effect and cannot begin to be determined from tree rings."
I prefer to call it Adendro Deficit Syndrome.
Wind is doing well on the coldest day so far this winter - 0.28% of total supply!
Dendrochronology is a great way of dating trees and pieces of timber, by matching the patterns of growth rings.
The ability of dendrochronology to identify why the growth one year was not the same as the one before or after, remains a bit iffy.
Those that remember 1976 in England (climate scientists don't like to remember it at all) will recall it was a hot dry summer, with droughts and stand pipes in the streets. It was not a good growing season due to water shortage. The autumn was actually very wet, with flooding, and the water table and reservoirs recovered their losses. How much of this is revealed by dendrochronology? I presume it is a narrow growth ring, but does that prove it was cold?
Dodgy Geezer , michael hart , golf charlie
Presumably talking about this paper at least in part; so my guess is hockey sticks.
SandyS, I think you are probably right.
I would imagine that some of the Scottish estates have dusty old ledgers and note books going back 100-200years plus, recording details in relation to shooting and fishing. Frozen lochs and rivers, river flows, heather flowering, snow falling and melting etc etc.
1815 was the Battle of Waterloo, it was also the Tambora eruption, leading to the 'summer that never was' due to volcanic dust etc. With Napolean defeated, many troops returned home, and domestic farming intensity would have changed. If I searched dendro records, I am sure I could find evidence consistent with these changes, but I am not sure if I would have 'proved' anything.
I wish Wilson well in his endeavours, and his graph does show a trough equating to about 1815, and then another one 20ish years later. Correlation or causation?
@golf charlie: That was when the then minister for drought, Dennis Howels, said in the October that before water restrictions could end, it would have to rain continuously from October through to January for stocks to recover, & it did precisely that!
Alan the Brit, I remember! The day after he was made Minister for Drought, he was fimed by the BBC, in a dried up reservoir, holding an umbrella due to the rain, smiling! Possibly one of the most successful political appointments of all time.
The summer drought of 1976, and the gale of 15/16th October 1987 are two significant weather events that I remember very well, but climate scientists like to pretend never happened. The BBC and Met Office suffer selective amnesia too.
@Michael
Bog oak I guess.
Scots pine certainly do not live for 1000 years
Yews (the oldest trees) rot from the inside at a certain age and are therefore unusable.
I don't dare to predict Dr. Wilson's conclusions. I have a great respect for Scotch whisky.
Somewhat off-topic, but highly relevant – please go to JoNova’s site.
RR - what a shock, and very sad.
https://www.youtube.com/watch?v=JpfMM3bVbhQ
"Napoleon's Piano"
800 years of tree planting forestry and timber production in the Cairngorms ,
So where is there an 800 year old plus tree in the Cairngorms Managed National Park.
Another Hockey Stick Illusion the Scottish version.
Jamspid - the oldest Scots Pines live to is about 600 years old, but Rob doesn't have to find living trees 800 or 1000 years old - just ones which fell into peat or still, acidic (and preferably cold) waters when they died, which can then be preserved for centuries. The archealogists on Loch Tay Crannog found a submerged Iron Age hazelnut in the peat/silt in Loch Tay which was still green - for about 10 minutes - before the oxygen got to it once it was brought to the surface. I don't doubt that trees and their rings can tell a story of good and bad growth years. But I certainly hae ma doots* that it is all down to temperature, especially when the datasets are carefully selected for the signal they are looking for, and dubious statistical methods are the norm.
*have my doubts - I am having a large dram for Bob Carter.
Unfortunately I cannot go to the event, but would like to. Listening to others, particularly when you think they might be wrong, is the way to learn and gain understanding.
One thing that I would like to understand is how the Wilson et. al 2016 managed to so closely replicate the actual temperature data. Compare a 15 year centered moving average of the average annual Wilson et. al proxy data that I created with the Gistemp data for the Northern Latitudes. There are remarkable similarities in the early C20th warming, the mid-century cooling and the late C20th warming. The only thing the tree rings failed to pick up was the pause in warming. This latter is no doubt due to the drop in proxy count from 53 up to 1988, to just 3 in 2011.
What's WRONG with you people? Who doesn't just adore trees? And look at that pretty picture! And read what it says! "loved by generations, cared for by you"
My heart is melting.
Morning All,
I would very much welcome anyone to pop by and see this talk. Please be open minded.
This is a "warts and all" talk - as is my style. I focus only on the Cairngorms as that is where the talk is given alhtough we have sampled right across the Scottish Highlands. More here: https://www.st-andrews.ac.uk/~rjsw/ScottishPine/
Just to clarify as a teaser - I have sampled ALL pine woodlands around the Cairngorms and used ALL sites to derive TWO independent reconstructions which agree very well.
The extended reconstruction uses sub-fossil remnant material preserved from lake sediments and only living trees growing close to those lake edges. The other reconstruction uses ALL OTHER data for the rest of the Cairngorms.
The big headache in Scotland for dendroclimatic work is human disturbance from felling - the worst place I have ever worked in this regard.
All will be revealed.
Rob
I am with Dodgy and OE and GC on this one but I'd still like to attend this lecture, since days long ago dendrochron' has always fascinated me and by God do I love TREES, though I don't climb them as much these days.
Lapogus,
Good points.Perhaps Bob Wilson could move up the road a bit from the Taymouth Cranog to Fortingall.
There he could demonstrate the presence of the Roman Warm period by taking (another) lump out of the Fortingall Yew.
After all, seeing as Pontious Pilot played in its branches as a youth before going to Palestine to help set up the Catholic Faith, he should have nay problem.
BTW where aboots is Rothimuchus Tennis Clubhouse?
Ah! That explains the photomontage, a bleak backdrop against which a few scattered trees, barely surviving, nonetheless endure. The allegory is powerful, masterfully depicting our uncertain future, the onslaught the forces of evil, and the handful of unnamed heroes that still resist in the name of the grandchildren of children yet to be born.
Lapogus,
Good points. Perhaps Bob Wilson could move up the road a bit from the Taymouth Cranog to Fortingall.
There he could demonstrate the presence of the Roman Warm period by taking (another) lump out of the Fortingall Yew.
After all, seeing as Pontius Pilate played in its branches as a youth, before going to Palestine to help set up the Catholic Faith, he should have nay problem.
BTW where aboots is Rothiemurchus Tennis Clubhouse?
So Dr Rob Wilson Question
So all these these Scottish trees you looked at do they prove man made global warming due to increased man made CO2
Answer either yes ,no or you don't know.