The take home point, which you still seem to miss, is that proxy data is not data. This may be due to the fact, as you say, we cannot travel backward in time but it raises several concerns that due to your tone and lack of simple understanding in this business of science I will now make clear to you.

In the business of measurement, arguably the most important aspect in the business of science, one must know a few things. First and foremost the quantity that one is interested in to begin with. Immediately after the identification this quantity, the most important aspect of measurement is uncertainty, or as we in the business of physical measurement call it, noise.

Now, as a big shot in your forestry office I will ask you this, what is the noise on a proxy measurement from modeled data? I'm sure you'll tell me that this isn't important. Fine, but how does one propagate the error associated with all the calculations undertaken bu Salzer et al? If one cannot propagate the error associated with calculating the predicted amount of tree growth the researchers should have seen in the trees used for this study then their conclusions are dramatically less significant if they could provide such error. Moreover, if they don't know the error from the proxies, they don't even really know what the proxy is saying about their current measurements, other than some correlations.

Now my analysis might seem stupid to you because ecological research, by and large, doesn't care about uncertainties because one just counts individual trees, but without knowing it, this type of research goes from ecology to physical science very quickly. If this is going to be case, ecology informing physical science, then it seems to me ecology should start living up to the standards of physical science, ie no more proxy data. If all of this climate change science is truly that important for humanity and the planet, we shouldn't be relying on data whose uncertainty can never be determined. It just seems scientifically dumb.

For anyone who is interested, the entire paper can be downloaded from the site

http://www-personal.umich.edu/~arury/Aaron%20Rury%27s%20Homepage.html

on the link starting with the tile 'Proceedings of the National...'

Hope that helps on the understanding side.

As to your question concerning the other 50 year period, according to the paper it was during the 2nd century BC. If you would like I can put the paper on my website and you can download it later.

I know most people don't have access to the PNAS itself so I won't hold it against anyone. The author of this piece, however, might be interested in reading the papers he cites before actually using them.

There is a key feature in this paper that gets passed over, as usual, by the 'science' writers here at Salon. The way these researchers correlate 'accelerated' tree growth with higher temperatures is via a proxy measurement. This means that no one actually measured temperature near the trees used to come to the conclusions made by the authors. There were in fact two proxies.

What is interesting is that one of the proxies they use to tell the temperature is from the trees themselves! So they use models that use tree data to tell the temperature, then they use the temperature proxy, from the tree data, to say something about the trees. Of course it's anomalous and accelerated, it's circular logic. Wonderful.

Then after they take this circuitous path, like-minded 'journalists' with a point to make irrespective of the quality of this work, take it up and pander it to the masses as truth. It's amazing how many at this site have such beef with organizations like Fox News when Salon is doing effectively the same thing, just with the opposite spin on it. Yet again I am applaud by the complete lack of any kind of critical thought by the writers and editors at Salon. Further vindication of why I shouldn't waste me time reading it.

A couple things. After searching through the article you cited from Science and then those that were referenced in other references, there are a couple questions I have. One, do these models assume a static carbon sink in the form of photosynthetic? I could not see it mentioned more than saying that plants can not use CO2 as fast as we're making it and that the models assume a "good" geographical land input. There was not much explanation of the different carbon sinks besides the oceans. Two, is it not true that most of these predictions, like that of 10 degree change in global mean temperature, are the high end of a range of possible temperature change that is tied to the uncertainty in the models? If these models give uncertainty in the range of 5 degrees for a 50 year integration, wouldn't they then give a larger uncertainty for a longer integration? I recently attended a talk at the University of Michigan given by Xianglei Huang who studies radiative transfer in the atmosphere. He showed that the standard GCM's underpredict the amount of outgoing longwave radiation and therefore, might be overpredicting the change in GMT because the atmosphere is not absorbing as much IR radiation. Also, the methane absorption band overlaps largely with that of the water vibration band, which is almost saturated right now. How could a change in absorption in these region of less than 10% greatly impact the climate?