Carbon what?! Carbon sequestration is just a fancy way to say “taking carbon out of the atmosphere.” While much of the work in combating climate change involves mitigating any future production of fossil fuels and emission of carbon, we have to deal with the excess carbon in the atmosphere. In 1800, before carbon emissions had really taken off, atmospheric levels of carbon were about 283 parts per million (ppm is, for every million particles of air, about 283 of those were carbon). As of 2020, that number has reached 414 parts per million, so fighting the climate crisis involves both a termination of new emissions, but taking old emissions out of the atmosphere to get back below 300 ppm.
Whether it is through burning coal, oil and gas, or even wood, new carbon in the atmosphere originates in the earth. But where does that carbon come from? Well, it is from the long-dead plants which soaked up atmospheric carbon, died, and ended up as part of the soil and earth. When we burn fuel, we are taking that old, earthbound carbon and releasing it into the air. So how do we sequester carbon? More plants! Since plants sequestered the carbon in the first place, plants can do it again.
This involves rethinking how we do agriculture. By reducing tillage and planting plants with long roots, we can store carbon deep in the earth while many of the nutrients in the soils remain or are replenished, making it an ideal technique for small-scale farmers. Strategies like this and deep composting are a part of what is called “Carbon Farming,” which allows small- and urban-farmers to grow produce while permanently sucking carbon out of the atmosphere.