Global Warming Can Be Reversed By Using Ancient Techniques

by VR Sreeraman on Dec 8 2008 12:52 PM

In one of the most serious attempts to reverse global warming, ancient techniques pioneered by pre-Columbian Amazonian Indians are about to be pressed into service in Britain and Central America.

According to a report in The Independent, the ambitious enterprise is the brainchild of two of Britain's most successful environmental entrepreneurs: Craig Sams and Dan Morrell.

Trials are to be started in Sussex and Belize early next 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 (CO2), the main cause of global warming, in the atmosphere and eventually bring it back to pre-Industrial Revolution levels.

Sams and Morrell aim to grow trees and plants to absorb CO2 and then trap the carbon by turning the resulting biomass into "biochar", a fine-grained form of charcoal that can be buried in the soil, keeping it safely locked up for thousands of years.

The pre-Columbian Indians used biochar to make the poor soils of the rainforest, which otherwise quickly become exhausted, productive for harvest after harvest.

It is still there today, many hundreds of years later, forming islands of black fertile earth in the otherwise unpromising ground.

But, it is now being widely cited as a possible solution to global warming by scientists.

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. Its founders hope that it will rapidly become a worldwide industry.

According to Sams, 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.

"Biomass from trees and plants, which captures carbon dioxide from the atmosphere, is a treasure to be buried in the earth," he said.