Turning CO2 into rocks to tackle climate change

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[Image changes to show a blue screen, and text appears: Carbonlock: Research Project Spotlight, Mineral Carbonation]

[Image changes to show Renee Birchall talking to the camera, and text appears: Renee Birchall, CSIRO]

Renee Birchall: I’m Renee Birchall and I’m a geoscientist working on carbon sequestration in rocks. 

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I’m working on something called mineral carbonation which is a naturally occurring process in nature that sequesters CO2 by reacting with the minerals in the rocks. 

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This is one of the ways that the Earth’s been managing its climate through the natural rock weathering cycle, and this has been happening for millions of years. 

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One of the ways we know carbonation works in nature is rainwater reacts  with the carbon dioxide in the atmosphere effectively sucking it out of the air and creating carbonic acid. 

[Image changes to show close views of rain falling on trees, and then on to rocks]

The rainwater then falls to Earth and weathers rocks forming bicarbonate and then stable carbonate.

[Images move through to show rain falling on to rocks, an aerial view of a river, and then a river mouth joining into the sea]

The carbonate is permanently and safely stored and stays in the soil then washes into the waterways and eventually the ocean. 

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We’re looking at speeding up those natural cycles and engineering the specific mineral reactions so we can scale up and increase the amount of carbon dioxide sequestered. 

[Images move through to show rocks moving through a crusher, and an aerial view of a mine tailings dam]

By engineering mineral carbonation, we can imitate this process using crushed rocks from industrial waste, including toxic mine tailings that can’t just be released into the environment. 

[Images move through to show mine tailings moving down through the rocks, a close view of rocks moving up a conveyer belt, rocks moving through a crusher, and then a barrel of cement being stirred]

Many of these industrial wastes and mine tailings already contain the necessary elements we need to react with carbon dioxide to create stable carbonates and even carbonate products like cement. 

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Precipitation of carbonates through adding crushed rock to soils will improve the soil health raising the pH, and also improve farm productivity. 

[Images move through to show Renee talking to the camera, a plane in the air, and views of large chimneys belching smoke into the air]

Engineered mineral carbonation can also be used as a stepping stone to assist fossil fuel-based industries in their pathway to net zero and in their emissions reduction strategies. 

[Images move through to show clouds scudding over a lake and mountains, and then a close view of water dripping off some rocks]

Of course, there’ll be concerns especially about the potential environmental impacts of these new technologies. In responding to these challenges, communication is key. 

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Having conversations with communities early, getting the right people in the room and achieving social acceptance from the beginning will help us move forward together. 

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That means having policy makers, First Nations representatives and the scientists, having those difficult conversations early in the piece. 

[Image changes to show an eroded coastline, and then the image changes to show a close view of water moving around the rocks on the shore]

We also need to make sure that our negative emissions technologies are responsive to decarbonisation strategies so that the two can go hand in hand.

[Image changes to show the CSIRO logo, and text appears: CSIRO, Australia’s National Science Agency]