Mark & Juanita wrote:
On 3 Jul 2005 00:41:19 -0700, wrote:
Mark & Juanita wrote:
On 2 Jul 2005 21:57:11 -0700, wrote:
... snip
This is the sort of nonsense one reads from junk scientists. There
is no doubt that humans have an effect on Global Climate. The issue
in controversy is the magnitude and direction.
Typical of the junk scientist is a tendency to try to reduce all
questions as a dichotomy and to claim (contary to fact) that
statistics can determine which answer is correct.
...
The global warming hysteria is a prime example. The idea that by
measuring tree ring size, one can determine the average temperature of an
area to within tenths of a degree is ludicrous, yet this is one of the bits
of evidence being used to show how average temperature is increasing
compared to several centuries in the past.
In general I tend to doubt stories presented without references.
In the instant case this sounds like it might be a misrepresentation
of some published work by a junk scientist (like Malloy) who most
likely didn't understand it in the first place.
... alright fred, present a credible source for how global temperature
change in tenths of a degree (which is the amount and rate being cited for
global warming evidence) can be identified for periods before accurate
weather records were kept.
Why should I? You haven't presented any credible source indicating
that anyone claims to be able to do so.
As you are so fond of saying, Google is your friend.
My first response was snide and I've deleted it.
What cuaght my eye was your statement "The idea that by measuring
tree ring size, one can determine the average temperature of an
area to within tenths of a degree is ludicrous."
A quick google search using the search terms "tree ring" and "average
temperature" does not yield anyoone making such a claim.
So, I remain skeptical that such a claim has been made.
Try to hearken
back to various debates in which the infamous "hockey stick" chart is shown
that attempts to show departures from average temperatures in 1961 to 1990
for the years 1000 AD to current time, showing this sudden jump of +.5C
when the other tempertures were below. The difference is less than 0.5 C.
The "measurements" from tree rings, corrals, ice cores and "historical
records" (remember that no calibrated met stations existed in 1000 AD) are
all being pegged at less than 0.5 C increments.
A Google search for "hockey stick chart" yields a few pages that come
up 404, perhaps due ot the NHL strike, and a few that criticize
"the hocky stick chart" but I haven't found any explanation of the
chart itself.
One example is found he
http://www.greeningearthsociety.org/...4/wca_24c.html
The chart appears to be a graph of temperature as a function
of time. Note the caption on the left side which indicates
the temperature origin is a "1961 to 1990 average." What is
meant by "1961 to 1990 average" is a mystery to me but inasmuch
as choice of origin is arbitrary let's not worry about
that.
It looks to me like the error bars (in grey--if those are
not error bars I don't know what they are) are about +/-
..5 degree for observations prior to about 1600, perhaps +/-
..3 degrees from 1600 - 1900 and I won't hazard a guess as
to what they are in the more recent data.
So, what again is your objection? Do you feel the the variance
in the data prior to 1600 was underestimated? If so, what
do you allege has been mishandled in the error estimation?
What do you mean by "pegged at less than 0.5 C increments"?
"Pegged" is usually used to mean a hard limit, for example met
sensor data showing relative humidity inexcess of 100% may be
arbitrarily adjusted to ("pegged" at) 100% at ingest, though
the term more often refers to a hard limit on the measurement
device itself (e.g. "pegging the meter").
The only 0.5 degree C increments I see are the major tick spacing
on the vertical (temperature) axis. Again, like the choice of
origin, that is arbitrary.
IOW, I don't see anything here to the effect of "that by measuring
tree ring size, one can determine the average temperature of an
area to within tenths of a degree is ludicrous."
If it is your intent to make another point, that point is lost
on me.
Fine, you are right. By rasing the average temperature of the area of a
city by one degree, you will have raised the "average" temperature of the
earth (depending, of course upon whether that city area is one of the
regions in which you take measurements to compute the average). Now, let's
see, a city on the order of 1000 square miles will contribute to the
overall average for the Earth's surface area of 197,000,000 square miles by
1/197,000, or a total influence of 5 microKelvin. Now, given that a fair
amount of that will be re-radiated into space, depending upon season, cloud
cover, etc, this amount is typically what most people would call
"negligible".
Maybe.
But people who use statistics know that statistics cannot answer
yes/no questions nor tell you how large an effect there is.
Statistics can only estomate the probability that the true
value of some measurable lies within some arbitrary amount from
a specific value.
That seems to frustrate a lot of people but Nature doesn't really
care.
--
FF