Thread Started on Dec 3, 2009
Are trees effective wooden thermometers?
Whereas we have thermometer records covering quite a large portion of the land surface of the planet going back about a hundred years how do we ascertain how the temperature varied BEFORE the modern era?
Well, we have historical records that show, for example, grapes were grown near Hadrian’s Wall in the Roman period and we know that there was a similar period of high temperatures known as the Mediaeval Warm Period when European agriculture thrived, population rose and the Vikings colonised Greenland and, again, grapes grew in Britain. The Bishop’s Palace of Lincoln Cathedral had its own vinyard. I visited it last year.
Until the rise of Global Warming Alarmism climatologists accepted as “normal” the alternation of periods of relative warmth and cooling in earths history and during the current inter-glacial period. This was the default model of “climate change” until about 1980 (and still is for many so-called "contrarian” climatologists).
From the mid-17th century to the mid-19th century there was also a cooling called the Little Ice Age when the Thames froze regularly and Frost Fairs were held on the ice, when the canals in Holland froze, too, giving rise to the lovely frozen landscapes of the Dutch School of landscape painting that we all love. The planet is STILL recovering from this dip in temperatures which is why there is indeed a slight upward trend to the figures today.
This cycle of warming and cooling that history revealed was a bit of an inconvnient truth for Alarmists because during those long centuries of both higher and lower temperatures CO2 levels were supposed to have been flat-lining at a much lower level than today. So the theory that extra CO2 emissions in the atmosphere from industrial processes were starting a runaway warming and climate instability was inconsistent with the record.
If the temperature had risen “naturally” WITHOUT the help of extra CO2 in the past the link between THE modern CO2 level and temperature rise was mere correlation and not causation. So they set about making the MWP disappear from the temperature record. Michael (aka Hockeystick) Mann was the proponent of this scam, aided and abetted by Al Gore and the dendro folk at CRU.
HOW did they do it? Well, Kiddies, they PRETENDED to believe that TREES could act as thermometers for the period before accurate modern instruments were available. Daft, I know - this is the part of the story that never gets told! And when they had fiddled with the tree ring data they pretended to find that the cyclical warming and cooling revealed in the historical record was largely wrong and that recent temperatures were really MUCH higher than in the historical past.
Unfortunately for them, modern era the treemometers, when compared to the ACTUAL instrumental readings for the last 50 years or so, showed a large disparity. They did not match the real thermometers at all - they showed a decline where the instruments showed an increase. In other words the wooden thermometers were not accurate proxies at all for real thermometers.
The dendro-palaeo-climatologists should have dumped these proxies there and then as useless but they didn’t want to discard the fine tool they thoought they had devised to show that the Roman and Mediaval Warm periods were not as warm as everyone had previously thought and that the modern period was by far the warmest for 4 millenia (thanks to extra atmospheric CO2, they proposed).
I think the dendropalaeoclimatologists had a bit of an undue "investment" in these proxies that so alarmingly departed from the known temperature. So they chopped off the “bad” proxy data and grafted the pre-1960 wooden thermometer graph on to the modern post-1960 instrumental thermometer record. This was very naughty. It has come to be known, thanks to the saga of the leaked CRU emails, as “Hide the Decline” - there is a comic song about in the Funnies thread.
There has also been a decline in world temperatures since the high temp year of 1998. But when the CRU scientists talk about “Hide the Decline” they are not talking this. They are referring to the totally crap "temperatures" produced by tree ring data, the implication that the historical record of warming in human literature and human memory CANNOT be over-ridden by proxy data manipulation and that the modern warming of the late 20th century is not “unprecedented” at all. This is the unpalatable fact that CRU was trying to hide by its “trick”.
No "unprecedented" late 20th century warming means there is no evidence that the very little extra CO2 in the atmosphere due to fossil fuel emissions can be shown to be CAUSING anything much at all! The current "global" temperature is clearly within the limits of “normality" as always believed until the 1980's. CO2 is rising very slightly but is not a problem. It fertilizes the plants and makes them grow bigger and better, including the rain forests and temperate forests that are carbon sinks. It is not a pollutant, it is an inherent part of nearly every process on earth living and inorganic.
Now you all know as much as I do, people.
Let science turn its attention to solving REAL problems not invented ones. And there are plenty of them!
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