This Ancient Bit of Ingenuity Keeps Carbon Trapped for Thousands of Years

For all its plant and animal life aboveground, the Amazon rainforest’s soils are surprisingly poor in nutrients necessary for growing food. Thousands of years ago, the region’s Indigenous peoples solved this problem by creating “terra preta” from table scraps and charcoal and tucking it away in the hostile soil.

Today, that ancient bit of ingenuity is a powerful climate solution. As biomass like trees and crops grow, they sequester carbon in their leaves and branches. Heat that biomass up without fully consuming it and it turns to nearly pure carbon known as biochar, which farmers soak in compost or fertilizer to “charge” it with nutrients, then add to their soils. That simultaneously improves crop yields and better retains water, all while locking carbon away from the atmosphere. Rising demand from farmers and big business is expected to push the global market for biochar from $600 million two years ago to $3 billion this year.