> Greenhouse effect is also settled
science (please see demo on youtube).

Of course. True but trivial and
essentially meaningless for the claims of
the alarmists.

If you regard that as evidence supporting
the alarmists, then you have been taken in
by trivia.

I learned about the greenhouse effect, the
role of Planck black body radiation, etc.
relatively thoroughly in ugrad physics
where the prof was big on such stuff and
had measured atmospheric absorption
spectra to help the US Navy with the
design of radar, etc.

Broadly, no doubt the people who
did the predictions reported in

http://www.energyadvocate.com/gc1.jpg

knew about the greenhouse effect, but
their predictions, and, thus, their
<i>science</i> was wildly wrong.

Now, let's look at some data, initially by
far the favorite data of the alarmists and
their early leader, Saint Laureate Al Guru
and his famous movie where he put up, from
ice core data, a big plot of temperature
and CO2 concentrations over the last
800,000 years or so.

Standing back, Al Guru claimed that the
CO2 and temperature went up and down
together and took that as proof that CO2
and its greenhouse effect caused the
temperature changes.

Nonsense. Total nonsense. Right there in
his data, total nonsense. Flim-flam
nonsense. Middle school level outrageous
incompetence.

If actually look at the data not from far
back but close enough to see actual
effects, then make three simple but
totally devastating observations:

(1) When temperature started to rise, CO2
was low, not high. So, something caused
the warming, but it was not CO2.

(2) About 800 years later, CO2 had
increased. Presumably the cause was more
biological activity from the higher
temperatures.

(3) Some thousands of years later, while
CO2 was high, the temperatures fell again.
There was a cause, but it was not low CO2.
Indeed, the high CO2 did not keep
temperatures from falling.

Net, from that 800,000 years of data,
there is no evidence that high CO2 caused
warming. It would be more accurate
(though of course still wrong) to say that
the data supported that CO2 caused
COOLING.

For some more recent data, there was some
significant warming during the time of the
Roman Empire and during the Medieval Warm
period, and there is no evidence that the
cause was high CO2. There was some
significant cooling during the Little Ice
Age from roughly 1300 to 1900, but there
is no evidence that the cause was low CO2.
There was some cooling from 1940 to 1970
and concerns in the media about another
ice age, and those years were when there
was more CO2 from human activity from WWII
and the post-war economic boom. So, in
those years, with more CO2, we got some
cooling instead of warming.

Again it would be more accurate (though of
course still wrong) to say that the data
supported that CO2 caused COOLING.

For some details, can start with "Global
Cooling" at

https://en.wikipedia.org/wiki/Global_cooling#1974_Time_magaz...

which discusses the two famous magazine
stories, the 1974 <i>Time</i> story and
the 1975 <i>Newsweek</i> story, worrying
about "global cooling" and asking if we
were entering a new ice age. For more on
these magazine stories, at

https://longreads.com/2017/04/13/in-1975-newsweek-predicted-...

can see the April 28, 1975,
<i>Newsweek</i> article “The Cooling
World”.

So, net, there is no data on temperature
and CO2 from the past that says that CO2
will cause warming.

Yes, CO2 is a <i>greenhouse</i> gas. This
means that it absorbs some light in the
infrared but not the visible. In the case
of CO2, it absorbs light out in the
infrared in three narrow bands. The
absorption spectrum is given at

https://webbook.nist.gov/cgi/cbook.cgi?Spec=C124389&Index=0&...

We have had some warming since the Little
Ice Age. It may be that we are still
pulling out of the Little Ice Age, e.g.,
it can take a long time for the oceans to
warm up. But even with this warming, it's
cooler than in the Medieval Warm period
and the Roman times when the polar bears
did fine, the ice in Greenland and the
poles didn't melt, the oceans didn't rise
and flood the coasts, and humans didn't
suffer. Apparently the main effects were
greater agricultural productivity, e.g.,
in England, grapes were grown for wine.

Could the warming since the Little Ice Age
be due to CO2? No: The warming is at the
surface, and CO2 absorbs high in the
troposphere with definition at Google:

<blockquote>the lowest region of the
atmosphere, extending from the earth's
surface to a height of about 3.7–6.2 miles
(6–10 km), which is the lower boundary of
the stratosphere. </blockquote>

which, from MIT climate scientist Richard
Lindzen, Alfred P Sloan Professor of
Atmospheric Sciences, Emeritus at
Massachusetts Institute of Technology, has
gotten cooler, not warmer.

So, net, CO2 really is a greenhouse gas,
but its warming effects are too small to
be significant or detected in the data on
temperature and CO2.