IF THE world cannot curb its carbon dioxide emissions, perhaps the obvious solution is to bury the CO2. But where? Abandoned oil wells, coal seams and salt mines are all possibilities. The safest place, though, might well be down in the ocean bed.
High pressures and low temperatures several hundred metres down in the sediment would ensure the CO2 quickly liquefied or formed frozen lattices with water called hydrates.
Even earthquakes would not shift it, says Kurt House, a geoscientist at Harvard University. Better still, the available storage space is vast. The US could store thousands of years of emissions within its own territorial waters, he says (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0605318103).
Advertisement
One worry is that if climate change warms up the oceans, the stored hydrates might be released back into the atmosphere, as might also happen with the methane hydrates that are already deep in the sediment. House says the bottom of the ocean would have to warm by more than 5 掳C for that to happen 鈥渨hich is very unlikely鈥�. Injecting CO2 into methane hydrates should be avoided, though, as it could destabilise them.
