Sumatra: the Sunda trench lies close by far beneath the ocean
By Michael Marshall
Here is a radical solution to dangerous climate change: create lakes of liquid carbon dioxide on the seabed, and keep the greenhouse gas out of the air.
As well as cutting our emissions of carbon dioxide, it is becoming increasingly likely that we will have to actively remove the gas from the air to keep Earth’s temperature at a safe level – which is now agreed to be no more than 1.5 °C above that in preindustrial times.
But where should we put the carbon? Most attention has focused on burying it underground, perhaps by injecting it into depleted oil and gas fields. This approach has been tested and seems to work, but it is unclear whether people will accept this fix.
Now Steve Goldthorpe, an energy analyst based in New Zealand, has suggested a radical alternative: dump the carbon dioxide in deep ocean trenches, where it can sit permanently as a liquid lake.
The crucial point, says Goldthorpe, is that once the carbon dioxide reaches a depth of about 3000 metres, its density exceeds that of water – so it will naturally sink to the bottom and stay there.
Very large carbon sink
Goldthorpe used Google Earth to explore the seabed and identify a suitable storage site. He found a deep ocean trench around 6 kilometres down, called the Sunda trench, just south of the Indonesian archipelago. “It is big enough to accommodate 19 trillion tonnes of liquid CO2, which is greater than all the CO2 from the total global fossil fuel emissions,” he says.
HT | Robert Woodward