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cannot be considered to be actually correct. Such an interpretation is
incomplete for it considers just a half of the precession forcing, 'cold summer',
whereas, one should account for an actually functioning full annual insolation
cycle, i.e. long cool summer and short mild winter or long cold winter and short
hot summer. It is the full annual insolation cycle for which the specific
mechanism of precession climatic forcing should be found.''
''
...
However, he was treating summer and winter as equal partners in high-
latitude climates, when in fact they are grossly unequal. At higher latitudes, winter
insolation is negligible and, at latitudes greater than 66.55
, there is actually little
direct winter insolation. Almost all direct insolation occurs in summer, so his
argument does not make sense.
Convinced that the conventional astronomical theory has fatal flaws (and he
may be right for the wrong reasons), he was led to believe that we should seek an
effect that changes total solar input to Earth (rather than seasonal variations at
high latitudes within a constant total input to Earth). In this regard, he focused
on eccentricity. He quoted Croll who said:
the glacial epoch could not result directly from an increase of
eccentricity, it might nevertheless do so indirectly. Although an increase of
eccentricity could have no direct tendency to lower the temperature and cover
our country with ice, yet it might bring into operation physical agents which
would produce this effect.''
''
...
Bol'shakov emphasized the role of feedback mechanisms in amplifying the
small signals from variable solar input due to eccentricity changes. He mentioned
positive feedback associated with albedo change—due to snow and ice volume and
vegetation cover change—and with changes in greenhouse gas concentration. He
also described enhancement of atmospheric circulation due to glaciation (the
higher temperature gradient from the equator to the poles increases the flow of
warm air toward the poles, reducing the temperature gradient) as a negative
feedback. However, this moist air can supply moisture to the growing ice sheets
and can therefore act as a positive feedback as well.
Bol'shakov claimed that the various feedbacks might not respond in equal
measure to the several orbital parameters. He said:
''The positive indirect relation caused by albedo change in mainly high
latitudes of the Earth is likely to enhance strongly the insolation signal associated
with variations of Earth axis inclination angle whose highest variations do also
occur in high latitudes. Atmospheric circulation speed changes, caused by change
of temperature gradients between pole and equator, are most likely first of all to
influence the same orbital signal.''
Bol'shakov argued that the three orbital parameters could operate
independently on the Earth's climate system, rather than acting in concert to
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