Earth may hide a lethal carbon cache

Carbon locked away deep within the Earth's crust could have profound implications on our climate, according to a meeting in the US last week. It has long been assumed that this "deep carbon," buried in old carbonate rocks, fossil fuels and ice lattices, could be safely ignored when it came to analyzing the effect of greenhouse gases on climate. But now it is emerging there is much more deep carbon ready to spew out than previously thought.