

Climate Change and Scientific Integrity - Caligula
http://lifesciencephdadventures.wordpress.com/2013/04/03/climate-change-and-scientific-integrity/

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manicbovine
The purpose of the Marcott, et al study was to understand what happened during
the last 11,300 years. We already know what happened during the last 100
years. (Nonetheless the uptick at the end of their graph is almost certainly a
byproduct of misaligned proxies.)

What's more, the FAQ selects quotes from the article; the FAQ offers no
additional information. In particular, from the article and FAQ:

>Without filling data gaps, our Standard 5×5 reconstruction (Figure 1A)
exhibits 0.6°C greater warming over the past ~60 yr B.P. (1890 to 1950 CE)
than our equivalent infilled 5° × 5° area-weighted mean stack (Figure 1, C and
D). However, considering the temporal resolution of our data set and the small
number of records that cover this >interval (Figure 1G), this difference is
probably not robust.

It's disingenuous to imply that this clarification was tacked on after the
fact, as the blogger suggests.

Finally, there's this from the blog:

> If your methods can’t resolve data points in a given period of time, then
> DON’T REPRESENT DATA POINTS IN THAT GIVEN PERIOD OF TIME.

Marcott, et al clearly state ( _in the paper_ ) that there is zero
preservation of variability in 300 year resolutions, 50% at 1000 year
resolutions, and nearly full preservation in 2000 year resolutions. This
blogger takes this to mean that the last 2000 years should be arbitrarily
trimmed from the graph. Following that logic, we might as well continue
trimming along the x-axis until nothing is left.

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JohnDakota
>Following that logic, we might as well continue trimming along the x-axis
until nothing is left.

The data is still useful in determining the statistical confidence of the set,
but not reliable for representation as its representation completely changes
the understanding conveyed by the data set. So the data stays in, and the
X-axis doesn't get trimmed. Only the data point, as represented in the last,
non-robust interval, gets trimmed.

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manicbovine
I'm not sure why, but I saw the graph differently. The last 2000 years are not
chopped off, as you correctly point out.

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oneiric
This is a ridiculous critique. We have thermometer data for the last 100
years. We don't need to look at rocks for that part. Chopping off the hockey
stick would be disingenuous, ignoring accurate data.

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JohnDakota
You do, actually. We only have non-thermometer data for the preceding 11300
years, so it is important to establish that the thermometer data correlates
with the non-thermometer data, so as to fully understand the trends in the
data. Imagine if MMTS stations greatly over/under estimate temperature values
relative to the non-thermometer methodologies. That would mean the preceding
11300 year baseline for the trend would be a misrepresentation.

This correlation of data acquisition appears to have been done until the
conversion of recording stations to MMTS stations. The correlation stop, at
that point, and we are now entirely dependent on thermometer data.
Coincidentally this is is also the 'hockeystick blade' time frame.

