A lot of money has been pumped into Carbon Sequestration recently, to try and put some of the CO2 we produce back into the earth in the underground aquifers where we got the oil and gas that caused it in the first place. However, another way of storing carbon is in the soil, which benefits agriculture as well. Indigenous tribes in the Amazon basin have been using a technique of introducing charcoal to soil to produce darker ‘terra preta‘ soil for millenia. The low temperature charring of plants and trees introduces more carbon to the soil and encourages worms to break down the charcoal and soil to make a nutrient-rich loam.
A study into the method by MIT professor Amy Smith found that using agricultural char methods could be a great way of producing low-cost fuel for developing nation. You can view a speech on the subject she made at TED 2006 here. By burning waste materials in a gasifier, the methane, hydrogen and other burnable gases it produces can be used as fuels, leaving behind a charred solid that can be mixed into the soil as fertiliser, building back the soil content. Because the organic content has charred, it doesn’t decompose to be released into the atmosphere. WorldChanging has a great analysis that the process could actually provide power whilst potentially reducing the amount of carbon in the atmosphere.