Long Debate Ended Over Cause, Demise Of Ice Ages? Research Into Earth's Wobble

ScienceDaily (Aug. 7, 2009) — Researchers have largely put to rest a long debate on the underlying mechanism that has caused periodic ice ages on Earth for the past 2.5 million years – they are ultimately linked to slight shifts in solar radiation caused by predictable changes in Earth's rotation and axis.
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The melting was first caused by more solar radiation, not changes in carbon dioxide levels or ocean temperatures, as some scientists have suggested in recent years.