Whether restoring trees, conserving existing ecosystems, rewilding native animals, or changing incentives to elicit better choices, targeted interventions can tap into feedback loops that can improve our planet, our economy, and our lives.

A feedback loop occurs when the outcome of a process restarts that process, creating a cyclical chain of cause and effect. Feedback loops can either maintain the status quo (a negative feedback loop), or they can create a “snowball effect” (a positive feedback loop) where more begets more. These feedback loops have been with us since the beginning of time, and they are implicit in the formation of everything that exists in the universe. Physical feedback loops literally form our physical reality around us, but psychological feedback loops determine how we build our perspective of reality.

In 2019, The Crowther Lab, which Tom Crowther runs at ETH Zurich, a leading Swiss public research university, published a study in the journal Science on the Earth’s carrying capacity for trees. Using satellite imagery, massive datasets compiled from thousands of studies, and computer models, they evaluated where trees could naturally grow on Earth. They estimated that the planet had room for an additional one trillion trees on land not currently in use by humans for farming or settlement—land that was once forest. And the model predicted that those recovering forests would capture one third of all human carbon emissions since the industrial revolution. Yet, lost in that initial discussion was the inclusion of the importance of biodiversity and care to ensure the reforestation efforts meant building millions of local feedback loops, where local people and nature thrive together. It meant millions of local communities, indigenous populations, farmers, and foresters working with nature to recreate whole, healthy, stable ecosystems as biodiverse as the ones we’ve lost.

In Nature’s Echo, Crowther explains the powerful force of feedback loops in nature and how, at the moment, our planet is experiencing a series of positive feedback loops as we hurtle towards environmental collapse. These feedback loops are too powerful to fight against. However, his research consistently shows that, instead of fighting feedback loops, we can harness their potential to create spectacular, worthwhile change. We can use feedback loops to help the Earth heal itself.