By Susan Milius
The idea seemed so catchy, simple and can-do. There’s room to plant enough trees, albeit many, many, many trees, to counter a big chunk of the planet-warming carbon spewed by human activities.
A more realistic look at that feel-good estimate, however, might shrink it down to a useful idea, but no panacea. The proposed fabulous benefits of planting trees triggered a skeptical backlash within the climate science community.
“Dangerously misleading,” warned a critique from Pierre Friedlingstein, a mathematical modeler at the University of Exeter in England and four colleagues. They’re not the only ones to protest that the original estimate — that massive global tree-planting right now might eventually trap a total of some 205 metric gigatons of carbon — overestimates what’s really possible.
The debate started with a study in the July 5 Science. In it, Jean-François Bastin and Tom Crowther of ETH Zurich and their colleagues estimated that Earth has as much as 0.9 billion hectares of land suitable for planting new trees to soak up some of humankind’s excess carbon dioxide and thus slow climate change (SN: 7/17/19). That area is about the size of the United States.