On Mar 2, 11:52 am, wrote:
On Mar 1, 6:11 pm, wrote:
...
So we are near a maximum, not a minimum. The last maximum
was around the end of the last ice age and we've had one
minimum roughly halfway between then and now, demonstrating
that large scale variation of the Earth's climate are not caused
(at least not soley) by those effects.


And, long-term climate change on the Earth is
driven by or at least heavily influenced by
long-term changes in eccentricity and obliquity.
That is over periods of time greater than the
precessional period:

http://www.livescience.com/forcesofn...arth_tilt.html
http://science.enotes.com/earth-scie...kovitch-cycles

Those are cyclical effects with periods of several tens
to a couple of hundred thousands of years.

The global warming being modeled based on the observed
change in CO2 concentration is a much shorter-term
phenomenon, over a period of a couple of hundred
years, superimposed on those long-term effects.

--

FF