Why should we store CO2 underground?

CO2 is being pumped into our atmosphere at an alarming rate. In 2012 it was reported that the combined total of CO2 released into the atmosphere was over 38 billion tons, which is the equivalent of over 108 KG per second! The Paris Climate Agreement seeks to reduce global carbon emissions in order to keep the Earth’s temperature to below a 2 degree increase on pre-industrial temperatures. Reducing world emissions is only part of the story of the fight against climate change. Removing CO2 from the atmosphere is also part of the solution. But once it is removed, where is it put?

One use for the CO2 filtered from the air is as a raw material. It can be used in fizzy drinks, food packaging, commercial green houses, and even turned into fuel to run your cars. The Climeworks’ carbon capturing plant in Switzerland, the first of its kind in the world, sends its captured CO2 to a local greenhouse, increasing productivity by around 20-30%. Using the CO2 in this manner reduces the burden on fossil fuel usage and encourages a circular economy. Only putting back into the air the CO2 taken from the air.

The Planet First campaign seeks to remove 100 tons of CO2 from the atmosphere, permanently. (Don’t forget to back the campaign here!) The best way to do this is to inject the CO2 deep underground, a process called carbon sequestration. Injecting CO2 underground is something that has been already been happening for quite a while, with the first commercial example the Weyburn-Midale Carbon Dioxide Project in 2000. Usually, it is injected into an geological formation, deep beneath the surface of the Earth. Depleted oil and gas fields and un-mineable coal seams have also been suggested as places to story CO2.

CO2 Storage (Wikipedia)

When the carbon dioxide has been captured and compressed into a so-called supercritical state, in which it is somewhere between a liquid and a gas, it is then pumped through a well into subsurface rocks, between 3,000 and 15,000 feet below the surface of the Earth.  Just like oil and gas, which has been trapped underground for millions of years the CO2 can be stored underground for very long periods. It works best when pumped into porous rocks that contain small open areas within the rock which enables the CO2 solution to move through the rock.

Recently, in Iceland, scientists found that CO2 injected underground into a Basalt formation actually turned into solid rock within 2 years. The CO2 is rapidly converted into stable carbonate minerals meaning that it will be locked into this solid form and will not ever be released into the atmosphere.

Trapping the captured CO2 under the ground directly mitigates against the high levels of CO2 being pumped into the atmosphere. We do not suggest that this is the entire solution. Emissions still need to be cut, renewable energy utilised, and other measures taken to reduce CO2 in the atmosphere, and keep out climate as healthy as possible, before it is too late.

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