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Tree rings and climate


meteorologist

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nope, there are now 2 pages of posts with data that refutes that assertion.

what was he 'caught' doing?

data mining for hockey sticks in proxy data.

"In 10,000 repetitions on groups of red noise, we found that a conventional PC algorithm almost never yielded a hockey stick shaped PC1, but the Mann algorithm yielded a pronounced hockey stick-shaped PC1 over 99% of the time."

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

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data mining for hockey sticks in proxy data.

"In 10,000 repetitions on groups of red noise, we found that a conventional PC algorithm almost never yielded a hockey stick shaped PC1, but the Mann algorithm yielded a pronounced hockey stick-shaped PC1 over 99% of the time."

http://www.uoguelph....hockeystick.pdf

So what about the independent paleoclimate reconstructions that used a conventional PC algorithm and STILL confirmed Mann's fundamental research? You do understand, don't you, that Mann and his team aren't the only ones to find that global temperatures were slowly declining until we started dumping gigatons of GHGs into the atmosphere?

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also of this has been debunked. do you have anything else?

Actually, none of it has been debunked.

It's actually correct that Mann's algorithms did in fact mine for certain proxies.

Again, it's all a matter of recorded fact. You can simply say it isn't. I can simply say the sun didn't rise in the East too.

Again, once again, it's all on record and Wegman's report corroborates M&M.

http://www.uoguelph.ca/~rmckitri/research/WegmanReport.pdf

And we can use Mann's own words

http://wattsupwiththat.com/2012/02/06/mann-trees-arent-behaving-like-i-want-them-to-volcanoes-to-blame/

“We know these tree rings capture most temperature changes quite well,” said Michael Mann, professor of meteorology and geosciences and director of the Penn State Earth System Science Center.

"Most".

LOL

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Problems with tree rings. The divergence situation... where in modern times tree rings don't actually match up with actual temperatures. Mann used proxies that are not proxies.

And..the degree of variability of individual data points is greater than the result.

Mann has not published his data and not published how he selected the various proxies. It's crucial in science for work be reproducible. That's the heart of the scientific method.

There are so many things that can determine a tree ring. Kinda like climate. I do not think temperature is the overriding indication of tree ring or that Co2 is all there is in climate change.

Tree ring science is the worst science to support AGW. There are other avenues that are more crediable.

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So what about the independent paleoclimate reconstructions that used a conventional PC algorithm and STILL confirmed Mann's fundamental research? You do understand, don't you, that Mann and his team aren't the only ones to find that global temperatures were slowly declining until we started dumping gigatons of GHGs into the atmosphere?

You don't seem to understand that this has nothing to do with the turn of the century, but everything to do with the MWP. I'm not claiming there hasn't been warming. There has. The issue is whether the warming is significant and unprecedented. That's the entire point.

And tree rings are a poor determinant of this. Again, the point of this thread.

And what about the numerous borehole works done that show the MWP?

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You don't seem to understand that this has nothing to do with the turn of the century, but everything to do with the MWP. I'm not claiming there hasn't been warming. There has. The issue is whether the warming is significant and unprecedented. That's the entire point.

And tree rings are a poor determinant of this. Again, the point of this thread.

And what about the numerous borehole works done that show the MWP?

The only borehole studies I've seen indicated that the MWP was a regional warming, and that even at its peak it was cooler than today's temperatures. If you know of peer-reviewed borehole research that indicates the MWP was at least hemispheric in scope then provide links to it. Remember that borehole readings are proxies, too, and that they have their own issues of accuracy and resolution.

Regional heat waves have occurred throughout history and I have seen several attempts to 'stitch' together a MWP by conflating heat waves in europe in one period, asia in a different period, north america in a third period and so on to try to create the illusion that the MWP warming was widespread. Sometimes the periods differ by centuries. Puh-leeze!

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You don't seem to understand that this has nothing to do with the turn of the century, but everything to do with the MWP. I'm not claiming there hasn't been warming. There has. The issue is whether the warming is significant and unprecedented. That's the entire point.

And tree rings are a poor determinant of this. Again, the point of this thread.

And what about the numerous borehole works done that show the MWP?

cheetah,

There was a MWP. The same scientific disciplines which are under attack here are responsible for our being aware of a MWP in the first place. Most conclude that the MWP was not as warm as today, but it may have been close considering the error bars provided by the proxy studies . After all we are less than 1C warmer than the coldest of the LIA. In some locals maybe it was warmer. We really can't say. Heck, we can't even be sure the MWP or LIA were truly global events.

The uncertainty of AGW would be considerably higher if it depended strongly on the proxy record of past climate. The proxy record is just part of the puzzle, and not really all that important given the reality of the physics involved and the estimated range in value of climate sensitivity. We are not so much concerned with the past as we are with the future. Knowing the past helps lower the uncertainty but the principle science is not dependent upon knowing the past in minute detail.

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cheetah,

There was a MWP. The same scientific disciplines which are under attack here are responsible for our being aware of a MWP in the first place. Most conclude that the MWP was not as warm as today, but it may have been close considering the error bars provided by the proxy studies . After all we are less than 1C warmer than the coldest of the LIA. In some locals maybe it was warmer. We really can't say. Heck, we can't even be sure the MWP or LIA were truly global events.

The uncertainty of AGW would be considerably higher if it depended strongly on the proxy record of past climate. The proxy record is just part of the puzzle, and not really all that important given the reality of the physics involved and the estimated range in value of climate sensitivity. We are not so much concerned with the past as we are with the future. Knowing the past helps lower the uncertainty but the principle science is not dependent upon knowing the past in minute detail.

Rusty - Mann actually denies the existence of the MWP. It is the problem that needed to be overcome to prove we are seeing man caused warming. After all, with a period before the LI warmer than today, one could very well simply state we are naturally recovering from the LI.

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Just to give some of you a refresher:

{email – 1683}

date: Wed, 7 Sep 2005 13:56:57 +0100

from: “Jonathan Renouf”

subject: Final thoughts

to: “Keith Briffa”

Hi Keith,

Good to talk to you this morning. Just a few thoughts to reiterate what we’re hoping to get out of filming tomorrow.

1) Your interview appears at a crucial point in the film. Up until now our presenter (Paul Rose, he’ll be there tomorrow) has followed two conflicting thoughts. On the one hand he’s understood that the world is currently getting warmer. But on the other he’s discovered lots of historical stories (the Bronze Age, the MWP, the LIA) which tell him that climate changes naturally all the time. In trying to resolve this paradox he’s come across this thing called the hockey stick curve, and he’s come to you to explain it to him.

2) Your essential job is to “prove” to Paul that what we’re experiencing now is NOT just another of those natural fluctuations we’ve seen in the past. The hockey stick curve is a crucial piece of evidence because it shows how abnormal the present period is – the present warming is unprecedented in speed and amplitude, something like that. This is a very big moment in the film when Paul is finally convinced of the reality of man made global warming.

3) The hockey stick curve shows that what Paul thought were big climate events (the Bronze Age maximum, the MWP, the LIA) actually when looked at in a global context weren’t quite as dramatic as he thought. They’re there, but they are nothing like as sudden or big.

4) Paul can question you on things like: How reliable is the hockey stick curve? How do you work out past climate (cue for you to talk about proxies)? What drives all the “natural” fluctations in climate (this can be answered in very broad terms eg it’s down to changes in the sun’s output, volcanoes etc)

Hopefully this makes it clear what I’m trying to achieve.

Look forward to tomorrow.

All best

Jonathan

Jonathan Renouf

Series Producer

Science Department

201 Wood Lane

London W12 7TS

http://www.bbc.co.uk/

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Just to give some of you a refresher:

{email – 1683}

date: Wed, 7 Sep 2005 13:56:57 +0100

from: “Jonathan Renouf”

subject: Final thoughts

to: “Keith Briffa”

Hi Keith,

Good to talk to you this morning. Just a few thoughts to reiterate what we’re hoping to get out of filming tomorrow.

1) Your interview appears at a crucial point in the film. Up until now our presenter (Paul Rose, he’ll be there tomorrow) has followed two conflicting thoughts. On the one hand he’s understood that the world is currently getting warmer. But on the other he’s discovered lots of historical stories (the Bronze Age, the MWP, the LIA) which tell him that climate changes naturally all the time. In trying to resolve this paradox he’s come across this thing called the hockey stick curve, and he’s come to you to explain it to him.

2) Your essential job is to “prove” to Paul that what we’re experiencing now is NOT just another of those natural fluctuations we’ve seen in the past. The hockey stick curve is a crucial piece of evidence because it shows how abnormal the present period is – the present warming is unprecedented in speed and amplitude, something like that. This is a very big moment in the film when Paul is finally convinced of the reality of man made global warming.

3) The hockey stick curve shows that what Paul thought were big climate events (the Bronze Age maximum, the MWP, the LIA) actually when looked at in a global context weren’t quite as dramatic as he thought. They’re there, but they are nothing like as sudden or big.

4) Paul can question you on things like: How reliable is the hockey stick curve? How do you work out past climate (cue for you to talk about proxies)? What drives all the “natural” fluctations in climate (this can be answered in very broad terms eg it’s down to changes in the sun’s output, volcanoes etc)

Hopefully this makes it clear what I’m trying to achieve.

Look forward to tomorrow.

All best

Jonathan

Jonathan Renouf

Series Producer

Science Department

201 Wood Lane

London W12 7TS

http://www.bbc.co.uk/

From that you see fraud and manipulation where the National Academy of Sciences does not.

Is it even remotely possible that what was happening here was an attempt to make sure the science would be accurately reflected in the film?

p200108c0g15001.jpg

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From that you see fraud and manipulation where the National Academy of Sciences does not.

Is it even remotely possible that what was happening here was an attempt to make sure the science would be accurately reflected in the film?

My point was to highlight just why the hockey stick was so important.

I dont' call it fraud, I call it somewhat manipulating. Some do call it outright fraud though. I think these guys believe in what they are doing and when it's on the margin they pull it in their direction.

But the hockey stick and tree rings are always and important part of this discussion.

I think I've read that the climate history before 1000 or 1400 AD is based on a single tree? A single tree??? Now I could be wrong, thought I read this somewhere.

this is good science?

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My point was to highlight just why the hockey stick was so important.

I dont' call it fraud, I call it somewhat manipulating. Some do call it outright fraud though. I think these guys believe in what they are doing and when it's on the margin they pull it in their direction.

But the hockey stick and tree rings are always and important part of this discussion.

I think I've read that the climate history before 1000 or 1400 AD is based on a single tree? A single tree??? Now I could be wrong, thought I read this somewhere.

this is good science?

Here is a good jumping off point to help answer questions like that.

SEE HERE

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