It might be considered an odd retirement hobby, but Greg Porteous spends his spare time making biochar. Biochar is a black, charcoal-like substance created by applying high heat to organic materials such as wood, plant matter and even sewage sludge. He makes it in his own backyard in Courtenay, B.C., where he has a kiln that he bought online. In goes the organic matter, like brush or old wood pallets, high heat is applied with little to no oxygen and, since there is minimal fire, the fuel is turned into biochar. …It’s a carbon removal tool that has been picking up steam over the past decade. The United Nations has said biochar is a good way to deal with wood waste because it can hold carbon in the soil.