On this new global map, huge swaths of land are dotted in green pixels. These are the areas that could potentially be recovered with forests that have disappeared, according to a new study—and in total, could help capture as much as two-thirds of the carbon that humans have pumped into the atmosphere since the industrial revolution.

Planting trees is far from the only thing that needs to happen to fight climate change. But the study makes clear exactly how much it can help. “Our research shows that it should really be considered to be a top solution that must be prioritized,” says Tom Crowther, a professor of global ecosystem ecology at ETH Zurich and one of the authors of the paper.

A UN climate report last year suggested that the world needs another billion hectares of carbon-sucking forests to have a chance of hitting the critical goal of staying under 1.5 degrees Celsius of global temperature rise. But other researchers had only rough estimates of how much space exists to plant new trees. The new study looked at thousands of photos of forests in protected areas to build a predictive model of how trees naturally grow in various climates, and then used Google Earth Engine to map out the rest of the world. Then they took out areas that are already used for farming or cities to see what was left.

Read the full article about planting trees to fight climate change by Adele Peters at Fast Company.