[ RadSafe ] Solar radiation causes global warming

Otto G. Raabe ograabe at ucdavis.edu
Mon Apr 30 21:39:20 CDT 2007

At 04:42 PM 4/30/2007, Dukelow, James S Jr wrote:
>It would be interesting knowing your basis for thinking
>this.  Atmospheric scientists who have used a variety of couple OAGCMs
>(coupled ocean/atmosphere general circulation models that capture the
>physical, chemical, and biological interactions that determine climate)
>to investigate the importance of various factors find that they cannot
>match 20th Century climate without roughly a 50% influence of greenhouse
>gases and aerosol-producing pollutants, 30-35% influence of solar
>variations, and the balance due to volcanoes and land-use changes.
>Further, you don't respond to Kai's comment about the post-85 data not
>supporting the solar influence hypothesis.  Why does it magically stop
>working in 1985, just before the two decades of most rapid warming?
>Radiation scientists who are grumbly about the politicization of
>radiation science would do well to focus on scientific research in the
>climate area, rather than transparently special-interest political and
>commercial pleadings.
April 30, 2007

Kai's reference to NCDC data does no show a drop in solar irradiance 
after 1985 but rather a continued high level in the last half of the 
20th Century. Remarkably, those data do not match the Danish 
Meteorlogical Institute sunspot cycle data that I referenced 
(attached as pdf) which closely correlate with all the global 
temperature data from about 1870 to 1985. No special aerosol cooling 
needs be invoked from1940 to 1970. So I should not have said there 
was a correlation to solar radiation (or irradiance) but rather to 
solar activity.

I am not an expert in this area, but I found an article with the 
following interesting quote at co2science.org:

"Knowing that variations in solar activity correlate closely with 
climatic variations, but that climatic changes attributable to 
changes in solar activity are much larger than can be explained by 
changes in solar irradiance, Shaviv realized that an amplifier of 
some sort must be involved in the solar/climate relationship. What he 
and many other researchers have suggested, in this regard, is that 
when solar activity increases and the weak magnetic field that is 
carried by the solar wind intensifies (providing more shielding of 
the earth from low-energy galactic cosmic rays), there is a reduction 
in cosmic ray-induced ion production in the lower atmosphere that 
results in the creation of fewer condensation nuclei there and, 
hence, less low-level cloud cover, which allows more solar radiation 
to impinge upon the earth, increasing surface air temperature (and 
vice versa throughout)."

This is further elucidated by "Solar Flares and Global Warming" 
Physical Review Letters, June 20, 2003, which says "A recent study by 
researchers at Duke University and the Army Research Office has found 
new evidence of a link between solar flare activity and the earth's temperature

Climate modeling is very complicated and there are no totally 
reliable climate models.  These models cannot predict accurately what 
will happen in even the near future no less in decades or centuries. 
Personally, I don't believe that the increment of carbon dioxide 
added to the air by people by combustion is a major factor in climate 
change. Perhaps more important is the cooling caused by the increased 
albedo of the earth associated with particulate air pollution. 
Overall, I expect that the solar activity models ultimately will 
prove the most reliable in modeling changes in the earth's temperature.


Prof. Otto G. Raabe, Ph.D., CHP
Center for Health & the Environment
University of California
One Shields Avenue
Davis, CA 95616
E-Mail: ograabe at ucdavis.edu
Phone: (530) 752-7754   FAX: (530) 758-6140
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