Agricultural Geogineering: Planting wheat for carbon sequestration?

While there is continued emphasis on developing “Carbon Capture and Sequestration” to ensure a continued life for Somewhat Less Dirty Coal (euphemistically called “Clean Coal“), there are win-win-win options for geoengineering and carbon capture, like biochar, that merit far greater attention and active pursuit.  Le Monde reported several days ago on yet another potential path for adapting agricultural practices to capture and sequester carbon from the atmosphere.

According to this reporting, some grasses grown in calcium-rich soils will lead to formation of calcium carbonate (e.g., chalk) and the creation of “a virtually permanent geological carbon sink.” And, the levels are not trivial.

Isotopic analyses have shown that this carbon-trapping is significant: it could reach 150 kg [330 lbs.] per year per hectare in a field of wheat.

How does that translate into actual impact versus current emissions? According to modeling, “the 2.5 million hectares of wheat cultivated in England could, in this way, absorb 14 million tons of CO2, or close to 3 percent of the country’s emissions.” Three percent isn’t a Silver Bullet solution (or even a “wedge”), but it is a nice taste for something that can be done potentially at close to no cost with quite rapid impacts. In part, that low to no cost: through using this process as a way to handle waste:

By enriching soils with calcium, we could, in fact, stimulate this process. Such calcium could come from volcanic rock quarries, which produce great quantities of it through the dust they generate. Demolition sites could also constitute another source of calcium, as could steelmaking.

The way this was discovered, via research at a quarry about how to do soil reclamation at the end of the quarry’s life, suggest even more possibilities. Mountain-Top Removal and other highly destructive mining operations are better off stopped (or done in far less damaging ways). The reclamation of existing (and future) sites might, on first glance, be able to be conducted in a manner that would enable reclaiming some significant amount of carbon as part of the entire process of trying to (re)create some form of “natural environment” on those sites.

This is preliminary, not settled, as a potential path for reducing carbon in the atmosphere. Enhancing natural processes like this (and, again, biochar) could represent a far more fruitful path for “sequestration” than seeking to pump CO2 into the ground. Our mounting concerns over Global Warming are giving rise to ever more research into potential paths for capturing and sequestering carbon. We should make sure that these natural processes are not given the short shrift, in financial and other terms, in investments in the research and development of carbon reduction technologies and approaches.


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