I knew nothing about biochar before reading this article, and now know a little more.
“The Importance of Soil Biology
As explained by Bates, soil microbes create what you might think of as a coral reef in the soil — a highly fertile area of water storage, air storage and nutrient storage that can nourish a wide variety of soil microbes. This soil biology makes for very nutrient-dense plants. That, in turn, allowed large civilizations to flourish in the Amazon. The charcoal also takes carbon from the atmosphere, sequestering it in the earth for long periods of time — thousands of years, typically, provided you don't use destructive agricultural processes such as tilling. So, this carbon sequestration benefits not only soils and plants but also the atmosphere. "Right now, at this point in time, we really need [carbon sequestration] for another reason; we need to have that timeout to give us some time to slow our emissions down, to go carbon-neutral. This is what you might call carbon-negative or a drawdown effect of carbon actually leaving the atmosphere, leaving the ocean and coming back into the land, where it had been, as fossil fuels, before."