Carbon dioxide is widely known to be the most prominent greenhouse gas. Reversing the trend of rising CO2 levels worldwide has become a major priority in all attempts to stabilize climate change and the health of the environment. Meanwhile, slash-and-burn agriculture (especially in the tropics) represents a major source of CO2, both directly (the burning of forests) and indirectly (deforestation means forests no longer trap CO2). Additionally, slash-and-burn destroys fragile tropical soils.
We add charcoal or "biochar" to agricultural soils, with the additional benefit of improving soil quality. Charcoal is a very stable form of carbon, sequestering CO2 captured by trees for hundreds or thousands of years without decomposing.
We use waste charcoal that would otherwise be treated as garbage. We stably capture CO2 for hundreds of years, at least. And in so doing we vastly improve the fragile tropical soils ability to hold nutrients. A new kind of black gold.