WASHINGTON—More than 3 trillion trees now grow on Earth, seven times more than scientists previously thought. But it’s also trillions fewer than there used to be, a new study concludes.
A United Nations-affiliated youth group had a goal of planting 1 billion trees and Yale forestry researcher Thomas Crowther was asked if planting that many trees would do anything to help combat human-made climate change. Trees capture and store heat-trapping carbon dioxide.
Crowther said first he had to figure out how many trees are on Earth and that number was far more than anyone expected: 3.04 trillion trees, according to a study published Sept. 2 in the journal Nature.
The previous estimate was 400 billion trees and that rough count was based on satellite images peering down from space. Crowther and colleagues used 429,775 ground-based measurements along with satellite measurements and computer models to get a more accurate figure.
