One last chance to save mankind by Gaia Vince
So are we doomed?
There is one way we could save ourselves and that is through the massive burial of charcoal. It would mean farmers turning all their agricultural waste – which contains carbon that the plants have spent the summer sequestering – into non-biodegradable charcoal, and burying it in the soil. Then you can start shifting really hefty quantities of carbon out of the system and pull the CO2 down quite fast.
Would it make enough of a difference?
Yes. The biosphere pumps out 550 gigatonnes of carbon yearly; we put in only 30 gigatonnes. Ninety-nine per cent of the carbon that is fixed by plants is released back into the atmosphere within a year or so by consumers like bacteria, nematodes and worms. What we can do is cheat those consumers by getting farmers to burn their crop waste at very low oxygen levels to turn it into charcoal, which the farmer then ploughs into the field. A little CO2 is released but the bulk of it gets converted to carbon. You get a few per cent of biofuel as a by-product of the combustion process, which the farmer can sell. This scheme would need no subsidy: the farmer would make a profit. This is the one thing we can do that will make a difference, but I bet they won’t do it.
Black is the New Green by Fiona Harvey
This ancient product of the Amazon is now the subject of intense scrutiny by climate change scientists. The tenacity of the charcoal of terra preta – retaining its fertilising properties over centuries – has given them an idea. Charcoal is a form of carbon, the burnt remains of plant and animal material. If it can stay intact in the earth for so long, without being released as carbon dioxide gas, why not lock up more carbon in the earth in this manner?
Scientists have begun to refer to the charcoal made from plants for the purpose of storing carbon as “biochar”. The theory is that biomass – any plant or animal material – can be turned into charcoal by heating it in the absence of oxygen. By taking CO2 out of the atmosphere, the impact on climate change could be huge.