Ancient techniques pioneered by pre-Columbian Amazonian Indians are about to be pressed into service in Britain and Central America in the most serious commercial attempt yet to reverse global warming.
Trials are to be started in Sussex and Belize early in the new year, backed with venture capital from Silicon Valley, on techniques to take carbon from the atmosphere and bury it in the soil, where it should act as a powerful fertiliser.
The plan is to scale up rapidly into a worldwide enterprise to reverse the build-up of carbon dioxide, the main cause of global warming, in the atmosphere and eventually bring it back to pre-Industrial Revolution levels.
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Trees and plants soak up carbon dioxide as they grow, but release it again as they are burned or left to rot. But burning them largely in the absence of oxygen, through pyrolysis, reduces the amount of the gas emitted by 90 per cent, and stores the carbon in the charcoal instead. It also gives off energy that can be used as an efficient biofuel.
If the resulting biochar is then buried in the ground it will stay there for some 5,000 years, keeping the carbon out of the atmosphere, and nourishing the soil while it is there. It also cuts down on the use of fertilisers; reduces the emission of methane and nitrous oxides, which are also greenhouse gases, from the ground; filters out pollutants; and retains water, thus combating flooding.
The new enterprise will start with wood grown in Suffolk and with prunings from the Belize cacao trees that supply Green & Black's chocolate. But its founders hope that it will rapidly become a worldwide industry.
Mr Sams calculates that if just two and a half per cent of the world's productive land were used to produce biochar, carbon dioxide could be returned to pre-Industrial Revolution levels by 2050.
I hope he is right.
See also: http://en.wikipedia.org/wiki/Terra_preta