Biochar – better than burning sheep
A while ago, a few beers drunk, I became embroiled in speculating about decidedly unconventional ways of controlling greenhouse gases. Two ideas lodged firmly enough in my memory to last until the next day: burning sheep and burying trees.
Now before any of you vegans start with the hate mail, I want to stress that this was a thought experiment. No lamb was subjected to even the lightest singeing. But you understand the logic…wouldn’t it be good if you had a machine that could range around marginal land (rather than attractive pasture) under its own steam, all the while turning biomass into a high-octane biofuel?
Use a sheep and you’d get wool as an additional by-product. Plus the UK proved the concept when it incinerated most of the cows in the country when BSE hit…
Tree burying seemed like a cheap and easy way of carbon sequestration (with technology that works today, rather than in twenty years’ time). Grow trees as fast as possible. Then throw them down a disused coal mine. Repeat ad nauseam. Of course, you’d get methane released as the trees rotted – but surely there’d be a way of sealing that in or tapping it off.
It turns out that tree burying isn’t such a bonkers idea – it’s just you need to bury charcoal instead. Or so I discovered today at a post-Poznan washup (hosted by IES, Globe and European Economic and Social Committee), where the best presentation of the day was from Craig Sams on biochar.
Craig founded the Whole Earth organic food brand and Green and Black‘s organic chocolate (both of which he has since sold). He’s now pushing charcoal as a low-tech solution to the climate change problem, working with Daniel Morrell, founder of the Carbon Neutral Company.
Craig’s pitch is as follows (for more detail see this white paper from the International Biochar Initiative):
- The world’s soil has lost a colossal amount of carbon due to centuries of intensive agriculture (accounting for about half of the current stock of atmospheric greenhouse gases).
- You can take biomass (fast growing crops that you grow specially, coppiced trees or even the crud that gathers on the forest floor), and turn it into charcoal using pyrolysis (you get some energy too).
- The char can then be added to soil (either in forests or on agricultural land), where it enriches it, reduces the need for nitrate fertilisers, and stores large quantities of carbon for the long-term (all, potentially, achieved through a myriad of grassroots schemes).
Craig dropped an eye-popping stat into his presentation. If all available land were devoted to biochar for just one year, then enough carbon could be sequestered to take atmospheric concentrations back to pre-industrial levels. Admittedly, we’d all starve for 365 days – but it shows the potential.
