A decade ago Scientist discovered what is known by the Indios as Terra Preta or Black Earth and turned out be a part of instruments at our disposel to combat climate change. A incredible BBC documentary from 2002 reveals this story.

Eliza Barclay from NPR writes:
You've probably heard of compost – that thick chocolate-colored stuff that's an organic gardener's best friend and supplies plants with all kinds of succulent nutrients.

But what about biochar? It's another ancient farming material made from slow-burned wood (also known as charcoal) that holds nutrients and water into soil without them draining away. And lately it has enjoyed a certain revival because it can also pull and store the carbon in greenhouse gases from the air. Everyone from California grape growers to home gardeners on YouTube is trying it out.

The use of Biochar to act as a carbon sink is causing quite a stir among environmentalists and scientists alike. This ancient technology of burning organic matter then burying it in the ground to fertilize crops may have been around for over 3000 years in the Amazon Basin, but the research that shows that this method of fertilization will also absorb some of the carbon in the atmosphere means that this could be a really viable solution to the long term problem of carbon over production.

Abstract
Biochar, a pyrolysis product of organic residues, is an amendment for agricultural soils to improve soil fertility, sequester CO2 and reduce greenhouse gas (GHG) emissions.
In highly weathered tropical soils laboratory incubations of soil-biochar mixtures revealed substantial reductions for nitrous oxide (N2O) and carbon dioxide (CO2 5 ).

Imagine if in a poverty-stricken sector of the equatorial band, littered with acidic soils barely fit for farming, there were jet-black patches of dirt, seeded with charcoal and so fertile that they could be planted continuously for over 40 years without applying fertilizer.

Then imagine that those patches were so loaded with carbon that they had six to seven times the amount of carbon per pound of the surrounding soils, that Western scientists could partially replicate the process through which the black earth was made, and that by burying carbon in earth they could augment soil fertility and, perhaps, leach carbon out of the atmosphere and reverse global warming.

Perhaps the jig is already up—too much detail. What we’re talking about is terra preta, or more colloquially, biochar, the Amazonian miracle soil.