The Biochar Debate is the first book to introduce both the promise and concerns surrounding biochar (fine-grained charcoal used as a soil supplement) to nonspecialists. Charcoal making is an ancient technology. Recent discoveries suggest it may have a surprising role to play in combating global warming. This is because creating and burying biochar removes carbon dioxide from the atmosphere. Furthermore, adding biochar to soil can increase the yield of food crops and the ability of soil to retain moisture, reducing need for synthetic fertilizers and demands on scarce fresh-water supplies.