OT:Global Warming and Junk Science

[Boaz Bezborodko]

I have recently been in an extensive argument on GW with some 
Anthropogenic GW promoters.  It is amazing the extent to which these 
people rally around each other in their defense of what seems to be some 
very incomplete science.  One particular case that comes to mind is the 
Mann Hockey Stick chart. 

A scientist by the name of Mann came up with an analysis of climate 
proxies that "proved" that the current rise in temperatures is both 
unprecedented and man-made.   The man-made part comes by comparing this 
with the growth of CO2, but this is not "proof" and would easily be 
disproved by the existence of the Medieval Warming Period (MWP).  What 
his chart has done, and what its supporters keep insisting is the case, 
is to "prove" that the Medieval Warming Period did not happen. 

According to anecdotal evidence the MWP was a period of very warm 
weather over a period of a few centuries.  During this period Greenland 
was full of arable land on which the vikings were able to sustain 
settlements and the Romans were cultivating vineyards in northern England.

The pro-AGW folks are saying that the MWP didn't really exist except as 
a short-term and regionally isolated blip on the global temperature 
record.  I think that it is so critical to their argument that current 
rises in temperature have to be human generated that they have blinded 
themselves.  The disturbing part is that this includes eminent 
scientists who are supposed to not be biased by the outcomes. 

What happened was that some econometric statisticians (McIntyre and 
McKitrick) evaluated the Mann work and found serious problems with it.  
Essentially they were able to get the same chart by feeding the program 
random data.  After years of work and pressure from Congress to open up 
the data used they found a lot of the causes for those errors.  One 
report by the National Research Council on behalf of the National 
Academy of Sciences analyzed the work and in their sumary said that what 
Mann said was "plausible".  What the summary did not say and what you 
have to piece together from various parts of the actual report is that 
Mann's critics were correct.  But instead of saying this the NRC study 
goes further by adding other studies that "confirm" Mann's hypothesis if 
not his work.  The study included a number of people who've already 
expressed their belief that AGW is real.

There is still, to this day, an ongoing argument about whether the MWP 
did or did not exist and whether the proxies chosen are valid for the 
comparisons being made.

What is certain is that a selection of which proxies to use has a huge 
impact on what you find.  Some proxies support the existence of the MWP, 
others don't, while still others that were believed to be accurate 
(usually this simply means they tracked recent temperatures reasonably 
well AND don't show an MWP) don't seem to track temperatures since they 
were first developed.

But all this controversy is not evidence that we don't yet know enough 
about what happened in the past, let alone what's going to happen.  No, 
it is merely evidence that Global Warming "deniers" are either in the 
pay of the oil companies or are unwilling to accept the "consensus" of 
the "experts".

Boaz