Refilling the Carbon Sink: Biochar’s Potential and Pitfalls

Dec 9, 2010

The idea of creating biochar by burning organic waste in oxygen-free chambers — and then burying it — is being touted as a way to cool the planet. But while it already is being produced on a small scale, biochar’s proponents and detractors are sharply divided over whether it can help slow global warming. It has an appealing symmetry to it: If we got ourselves into this climate mess by digging up and burning coal, maybe we can fix it by creating some more coal and putting it back into the ground. That very idea, involving the charcoal-like substance known as biochar, has been both touted as a planet-saving climate change mitigator and then ridiculed as yet another tilt at the proverbial windmill.

Biochar has been lumped in with other so-called geoengineering ideas like solar radiation management and ocean fertilization, but it carries ancillary benefits to agriculture that the other planetary experiments can’t claim. The last two years have seen a sharp rise in research indicating its technical potential, and while the world treads carefully around other geoengineering fixes, there are now dozens of companies already producing and selling biochar on a small scale. Is large-scale deployment really feasible, or is it time for a step back and to take a harder look at whether this is a technology worth pursuing?

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