/sci/ - Science & Math

>>16178821
https://skepticalscience.com/Tree-ring-proxies-divergence-problem.htm
>I am confused. THere seems to be a logic problem here. If the proxies are incorrect post 1960 or there is a divergence at one time and you don't really KNOW the cause for that divergence then how can anybody conclude that there weren't other divergences you didn't understand in the past? Just because we don't see divergence between north and south there could be something which affected tree ring data over any period of time in the past either depressing or increasing temperatures that actually ocurred. You really can't have any confidence in this proxy until you understand the cause. What if the cause is caused by droughts? What if there was a large drought over the areas north and south covered by these trees? What if there was a huge flood or volcanoes or some other co-incidence like a increase in acidification due to some bacterial or animal or plant extinction or proliferation? The point is not the specifc thing but the logic being used here which is flawed by you guys. The fact is that the "science" is still very nascent and major things like what is affecting tree ring densities and widths is not really understoof even TODAY let alone 1,000 years ago

>>6627774
I made an error. I should have said the data started diverging during the 60s instead of 80s. Image related. I pulled it from the following study: http://eas8001.eas.gatech.edu/papers/Briffa_et_al_PTRS_98.pdf

The researchers say they are hiding the decline because that is what they are doing. The tree data diverges during the 1960s; tree ring data suggests that temperatures plummet from the 60s, which is not in line with recorded data. The researchers are hiding the decline by using different data, since they know it is not reliable. This is not because of malicious intent, however; they openly state what they are doing in their paper.

>Shouldn't they stop using tree ring data as a temperature proxy entirely, then? Isn't this what they should be talking about doing?

Some scientists have discussed this. In fact, tree ring data is excluded in some data sets, but tree ring data is not abandoned entirely. When all else is equal, tree ring data does successfully measure temperature, and it still gives us a fairly good insight on what was going on in the world in the past. It's not flawless, so scientists know that tree ring data is not conclusive, but it is still useful. As time and research continues, tree ring information becomes more and more accurate of a tool of measuring past events as our understanding of it improves. Using it as a tool is generally fine, so long as people know the limits of the tool they are using.