The Global Warming Debate

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(10-07-2012 03:43 PM)refill Wrote:  Here is a pretty good site I came across that counters a lot of the skeptic arguments:
http://www.skepticalscience.com/Tree-rin...roblem.htm

...including much of the minutia around tree-rings, cones, etc.

In my opinion, there are lots of strawman arguments on the internet that use the simple point-counterpoint format. It frequently turns into either a strawman or false dilemma. In my opinion, SkepticalScience.com is notorious for this type of argument. The article in the link that you gave is an example that discusses the “divergence problem.” Skeptical Science presents the skeptic argument using a quote from Steve McIntyres Climate Audiit. So far, so good.

Quote:Tree-rings diverge from temperature after 1960
Actual reconstructions "diverge" from the instrumental series in the last part of 20th century. For instance, in the original hockey stick (ending 1980) the last 30-40 years of data points slightly downwards. In order to smooth those time series one needs to "pad" the series beyond the end time, and no matter what method one uses, this leads to a smoothed graph pointing downwards in the end whereas the smoothed instrumental series is pointing upwards — a divergence (Climate Audit).

SkepticalScience then gives a condescendingly labeled rebuttal, “What the science says…” The summary paragraph is in the quote below:

Quote:The divergence problem is a physical phenomenon - tree growth has slowed or declined in the last few decades, mostly in high northern latitudes. The divergence problem is unprecedented, unique to the last few decades, indicating its cause may be anthropogenic. The cause is likely to be a combination of local and global factors such as warming-induced drought and global dimming. Tree-ring proxy reconstructions are reliable before 1960, tracking closely with the instrumental record and other independent proxies.

There is no evidence that the divergence problem is “unprecedented.” There are very few temperature sets made before the 20th century, and even those have reduced accuracy, and none of those early temperature records exist near the dominant tree cores. It’s impossible to rule out pre-twentieth century divergences. If the tree cores don’t show warming in the later 20th century, how do we know that the tree cores don’t show warming that occurred earlier. Other temperature reconstructions clearly show a strong Medieval Warm Period (MWP) about 1000 years ago. These tree cores aren’t used in the hockey stick reconstructions.

I came across the Skeptical Science website years ago, and I wasn't impressed. It seemed to a collection of strawman-based one sided arguments.