Federal Energy Minister Martin Ferguson and his Victorian peer Peter Batchelor seemed oblivious yesterday to their brush with geological time.

They pretended to open the valve on a pipeline which is as of this morning sending 100,000 tonnes of dense CO2 into a carbon crypt under farmlands east of Warrnambool where it will remain trapped beneath a layer of impervious rock for as long as Australia is recognisable as a continent.

For tens of millions of years. But maybe not.

There are quirky things about carbon sequestration, which is seen as a key to clean coal technologies, that seem to have escaped notice on a momentous occasion that makes more usual political photo opportunities like bridge openings seem ephemeral in comparison.

The wind storm that wrecked parts of SE Australia actually broke the power supply to the pumps that force the supercritical or fluid-like mass of CO2 into its prison, but the photo opportunity proceeded.

The sequestration demonstration is important for the coal and oil lobbies, and very annoying for some environmentalists, because if it works, it could underpin processes that could eliminate most of the man made greenhouse gas emissions that are derived from fossil fuels like coal, oil and natural gas.

But this is where the recent comments of Professor Will Steffen at the ANU put the risks and possible rewards of carbon crypts in sharp focus. Steffen says mankind is creating a new geological epoch which might be called the Anthropocene because of the mass extinctions of species of plants and animals associated with the acceleration of human impacts on the planet.

In a his co-authored paper Steffen says carbon sequestration would not only mitigate global warming but reduce the acidification of the oceans caused by their being overwhelmed by dissolved carbon which other researchers say is damaging the marine food chain.

But Steffen and his colleagues also point to the possibility than in the deep future, tens of thousands of years from now, a world that has long mastered clean energy may be confronted by the cyclical onset of the next ice age.

Our distant descendants might well, they suggest, liberate the sequestered carbon to quickly warm the atmosphere and thwart the serious consequences for agriculture, and civilisations, of a planet that turns very cold as the seas retreat and the ice caps advance.

All of which raises the thought that the wind-swept site of the southern Otway carbon crypt could be visited in a far distant time by tomb raiders trying to save themselves from global cooling not warming.