THE idea that wobbles in the Earth's axis caused the ice ages is on a roll again. Strong evidence to support this "astronomical theory" has emerged, despite the counter-argument that interglacial warming began before changes in the orbit could have triggered it.
In last week's
These dates match the times when the northern hemisphere was warmer because it was tilting more towards the Sun than usual. The tilt changes because of a small periodic wobble of the Earth's axis known as the Milankovitch cycle. "In all three instances we dated, the record was consistent with the astronomical theory," says Edwards.
The new dates are fairly ...
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