To: Moominoid who wrote (32504 ) 4/27/2003 1:50:12 AM From: Raymond Duray Read Replies (1) | Respond to of 74559 MILANKOVICH CYLCLES AND GLACIATION Moominoid, I think that this may have to be considered a very good theory of climate change: homepage.montana.edu <SNIP> Milankovitch Cycles and Glaciation The episodic nature of the Earth's glacial and interglacial periods within the present Ice Age (the last couple of million years) have been caused primarily by cyclical changes in the Earth's circumnavigation of the Sun. Variations in the Earth's eccentricity, axial tilt, and precession comprise the three dominant cycles, collectively known as the Milankovitch Cycles for Milutin Milankovitch, the Serbian astronomer who is generally credited with calculating their magnitude. Taken in unison, variations in these three cycles creates alterations in the seasonality of solar radiation reaching the Earth's surface. These times of increased or decreased solar radiation directly influence the Earth's climate system, thus impacting the advance and retreat of Earth's glaciers. It is of primary importance to explain that climate change, and subsequent periods of glaciation, resulting from the following three variables is not due to the total amount of solar energy reaching Earth. The three Milankovitch Cycles impact the seasonality and location of solar energy around the Earth, thus impacting contrasts between the seasons." <End Snip> ******************** My gravest concern about our present period of world-wide temperature rise is the potentially catastrophic effects this could have if we somehow have an abrupt change to the pattern of ocean currents, as has happened in the distant past: firstscience.com