Carbon Sequestration – September 16, 2020


Today we talk about carbon sequestration, the long-term natural or artificial storage of carbon dioxide or other forms of carbon from the atmosphere. There is a series of checks and balances that happen on the planet: atmospheric carbon dioxide gets taken up by biomass such as plants and trees, with these carbon “sinks” offsetting carbon “sources” that come in the form of wildfires and fossil fuel emissions from industry and automobiles. Oceans take up carbon dioxide naturally, but there’s a limit before the waters start to change chemically: they acidify, affecting marine critters’ abilities to grow shells, changing the delicate balance of the ecosystem which affects the entire food chain from plankton to fish to us. It is clear from the scientific evidence collected from all the “spheres” of this planet that we are out of balance. As mentioned in a previous Science Wednesday, atmospheric and marine accumulation of greenhouse gases is causing changes on our planet at unprecedented rates.
So, what can we do about it, on a global scale? The obvious answer is to reduce our emissions. But as developed nations continue to consume and developing nations strive for the same comforts of modern living, this is a tall order. With the COVID-19 pandemic and all the reduced travel globally this year, carbon emissions went down 10 – 30%, which seems like an impressive range. Unfortunately, it had just a temporary effect on reducing climate change (…/covid-19-coronavirus… ). Once carbon dioxide is in the atmosphere, it remains up there for centuries. So, it will take a lot more than one year of slight reduction in emissions to have any kind of impact. There’s already a lot of CO2 “in the pipeline” that will continue to impact us. We need a sustained effort and green policies at the government levels across the world.
Given political inaction, what else can be done? One technique is to store carbon dioxide in underground geological formations. The gas gets pressurized until it becomes a liquid, then gets injected into porous rock formations and/or depleted oil and gas fields. Stored at a depth of at least one kilometer, over time the liquid turns into a harmless carbonate mineral like calcite. You may know this mineral as it’s found in rocks like limestone and marble (metamorphosed limestone). In Iceland, which is known for its porous volcanic rock (rock with lots of holes), carbon capture and storage has been shown to work effectively at carbon disposal with dissolved CO2 being injected into the rock, rapidly transforming it to minerals. Read more here:
Many carbon capture and storage techniques are now in operation in the US, Canada and Europe, capturing hundreds of thousands of tons of carbon dioxide as they get released from coal plants and natural gas power stations and before reaching the atmosphere. But they are still very much at a small-scale and in various stages of development, worldwide. However, the fact that the technology exists and is shown to work is very promising. Check out one technique here:…/2019/01/190131113834.htm
Feel free to share in the comments other examples of carbon sequestration and storage!