BBC: Green guru James Lovelock claims that the only hope of mitigating catastrophic climate change is through biochar – biomass "cooked" by pyrolysis. It produces gas for energy generation, and charcoal – a stable form of carbon. The charcoal is then buried in the ground, making the process "carbon negative". Researchers say biochar can also improve farm productivity and cut demand for carbon-intensive fertilisers. There’s a flurry of worldwide interest in the …