Is it just bad science to perform temperature reconstructions using tree ring data?

Question

Tree ring widths do not have a linear correlation to temperature past a certain point. Most of the tree ring samples on which the Hockey Stick reconstruction and related reconstructions were based ended in 1980. When you bring the tree ring data up to date, the post-1980 warming doesn't show up, using the methodology that warming shows up as wider tree rings.

So how is it scientifically valid to continue to assume such a linear correlation and apply it to the past, or to justify the notion that past warm periods didn't occur because they don't show up as wider tree rings?

Or is the real motivation the fact that once you strip out the tree ring data, the MWP shows up again?

Answer 1

Its not enough to rely just on tree ring data. Its not only temperature but precipitation and many other factors which determine the width of rings.

Answer 2

because they only go back 5000 years they are of limited use.

the reasons to use tree rings is to make people believe that they are doing research showing global warming when the are only going back to a point after the last cooling cycle started.

http://en.wikipedia.org/wiki/Prometheus_...

sea bed sediments go back millions of years

Answer 3

The fact is, it's not just tree ring data that scientist use...

"Scientists have also developed a variety

of methods for estimating how the Earth’s

climate varied prior to the mid-19th century,

when thermometer measurements first

became widely available (see Figure 11).

For example, ice cores are drilled in polar

and mountain ice caps and analyzed to

reconstruct past climate changes; in addition

to analyzing the isotopes of hydrogen

and oxygen atoms that make up the ice to

infer past temperatures in the region, the

bubbles trapped in the ice can be sampled

to determine past concentrations of greenhouse

gases. Tree rings, corals, ocean and

lake sediments, cave deposits, and even

animal nests have also been analyzed to

estimate past variations in climate."

http://dels.nas.edu/dels/rpt_briefs/clim...

Answer 4

Tree ring dating (dendrochronology) has known limitations and "challenges" such as you describe, and more.

However, tree rings can give reasonably accurate results if interpreted correctly.  It is not a discredited science.  Unfortunately, we do have some discredited scientists performing the interpretations.