I usually agree with George Monbiot and love the way he says it but this time – with his assertion that the latest miracle mass fuel cure, biochar, does not stand up – he has got it only half right.

Yes, it is silly to rename charcoal as biochar and yes, it would be wrong to plant anything specifically to make charcoal. So I agree, George, it would be wrong to have plantations in the tropics just to make charcoal.

I said in my recent book that perhaps the only tool we had to bring carbon dioxide back to pre-industrial levels was to let the biosphere pump it from the air for us. It currently removes 550bn tons a year, about 18 times more than we emit, but 99.9% of the carbon captured this way goes back to the air as CO2 when things are eaten.

What we have to do is turn a portion of all the waste of agriculture into charcoal and bury it. Consider grain like wheat or rice; most of the plant mass is in the stems, stalks and roots and we only eat the seeds. So instead of just ploughing in the stalks or turning them into cardboard, make it into charcoal and bury it or sink it in the ocean. We don't need plantations or crops planted for biochar, what we need is a charcoal maker on every farm so the farmer can turn his waste into carbon. Charcoal making might even work instead of landfill for waste paper and plastic.

Incidentally, in making charcoal this way, there is a by-product of biofuel that the farmer can sell. If we are to make this idea work it is vital that it pays for itself and requires no subsidy. Subsidies almost always breed scams and this is true of most forms of renewable energy now proposed and used. No one would invest in plantations to make charcoal without a subsidy, but if we can show the farmers they can turn their waste to profit they will do it freely and help us and Gaia too.

There is no chance that carbon capture and storage from industry or power stations will make a dent in CO2 accumulation, even if we had the will and money to do it. But we have to grow food, so why not help Gaia do the job of CO2 removal for us?

• James Lovelock is an independent scientist, author, researcher, environmentalist. He is known for proposing the Gaia hypothesis.