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On Thu, 20 Feb 2003 22:18:55 +0000, Daniel B. Wheeler wrote:

"Titan Point" wrote in message
...
On Wed, 19 Feb 2003 10:31:25 +0000, Daniel B. Wheeler wrote:

[snip]
The debate is not about global warming but about anthropogenic global
warming.
According to Warren Washington, that is not the debate. You are welcome
to disagree, of course. But the increased temperature globally within
the last 30 years strongly points to some particular effect which has
taken place or has accumulated within that time frame.

Funnily, satellite records calibrated with randio-sonde measurements have
found practically no increase in lower atmospheric temperature since 1979.
The increase of the last 30 years is nearly lost in the statistical noise.
By no means is the range of temperature rise over the last century,
unusual or unprecedented.

So whatever Washington thinks about the record of climate change in the
last 30 years appears to be entirely removed from what was actually
recorded.


The climate has warmed about 0.6C since 1900. There is no dispute about
this from anyone. The question is whether the increase in carbon
dioxide - over and above that which would be expected to be produced by
a warming climate - is significant to force the climate warmer in a
significant AND biologically negative way.
The temperature has increased nearly a full degree Fahrenheit since
accurate temperatures have been kept, about 1970 I believe. While I
don't know about your figure of .6C since 1900, the increase of 1 degree
F. since 1970 is, I believe, well documented. And that figure was
assessed in 1990, after only 20 years of data. CO2 concentrations were
likewise also observed to increase.

The satellite record shows a decadal increase of (Spencer and Cristy)
0.075C/decade or 0.225C over the last 30 years. It is also misleading to
begin your measurements in a known cold period and then act surprised when
you show a warming trend. That is called end-date distortion.

According to measurements taken over the last century from properly
maintained, rural temperature stations, the warmest decade of the 20th
Century was the 1930s (for example 1934 saw fully one half of the
contiguous US in extreme drought, the "Dustbowl" years)

The very faint rise since 1970 is neither unprecendented nor surprising.

The rise in carbon dioxide during the 20th Century appears to be a
confounding factor rather than cause of 20th Century warmth.


Even that net rise disguises a lot of variation. The warmest decade of
the 20th Century was the 1930s, and temperatures are not quite as high
now as they were then. Temperatures during the 17th Century were some
1C lower than they are today. Temperatures during the 12th Century were
around 1.5C warmer than they are today. Temperatures during the last
major glaciation were 5-6C cooler than they are today. Temperatures
during the Eocene period 50 million years ago, were around 5-6C warmer
than they are today.

Accuracy of temperatures in previous eras is beyond my field of
expertise. I know of no individual who was present and keeping records
during the Eocene (or even the Pleistocene).

That's why climate scientists use a variety of temperature proxies, such
as relative isotopic concentrations taken from sediments and ice cores to
reconstruct past earth climate.

Warren Washington's comments were based on computer modeling which he
designed, and which have accurately predicted not just the current
worldwide temperatures, but also temperatures dating back to the 1900s.
As Mr. Washington noted, there are problems with even this computer
simulation. But at this time, it is by far the most accurate assessment
of current data known. Implications of temperatures from the Oligocene,
Pliocene, Pleistocene or Devonian will require several more generations
of computer simulation, I suspect.

Unfortunately not so. They do not reconstruct the past climate of even the
last 50 years, fail to model the fall in temperature at the South Pole and
make not attempt to seriously model the large greenhouse gas by far: water
vapor. Also Washington makes an assumption of stable solar flux which is
demonstrably false.

Speculation of climatic conditions millions of years ago do not
constitute any similarlity to present atmospheric conditions.

But computer models are speculation, not fact.