Iron-rich dust fuelled 4 million years of ice ages

Iron-rich dust fuelled 4 million years of ice ages – environment – 03 August 2011 – New Scientist.

DUST is all that’s needed to plunge the world into an ice age. When blown into the sea, the iron it contains can fertilise plankton growth on a scale large enough to cause global temperatures to drop. The finding adds support to the idea of staving off climate change by simulating the effects of dust – perhaps by sprinkling the oceans with iron filings.

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an oceanic desert because it lacks the iron crucial for plankton growth. That changes at the start of ice ages, when a wobble in the planet’s orbit causes an initial cooling that dries the continents, generates dust storms – particularly in central Asia – and sends dust onto the surface of the Southern Ocean.

The plankton that then bloom take the carbon they need from the water, causing the oceans to absorb carbon dioxide from the atmosphere to compensate. This cools the atmosphere further, creating yet more dust-producing regions, and the cycle continues, sinking Earth into an ice age.

This adds support to the notion of fertilizing the oceans with iron to increase plankton growth and sequestration of carbon (without acidification).  Experiments to date haven’t produced significant results, but that does not rule out the technique.