Is planting trees to combat climate change ‘complete nonsense’?

Bill Gates is emphatic: “I don’t plant trees,” he declared recently, wading into a debate about whether mass tree planting is really much use in fighting climate change.

The billionaire philanthropist was being probed on how he offsets his carbon emissions and insisted he avoids “some of the less proven approaches.”

The claim that planting enough trees could solve the climate crisis is “complete nonsense”, he told a climate discussion organized by the New York Times last week.

“Are we the science people or are we the idiots?”

A group of scientists warned on Tuesday that mass tree planting risks doing more harm than good, particularly in tropical regions. That’s primarily because it can replace complex ecosystems with monoculture plantations.

Major tree planting commitments often involve agroforestry or plantations, where the trees will eventually be felled, releasing carbon. And they are dominated by five tree species chosen largely for their timber and pulp value, or growth speed. Among them is teak, which can overtake native species.

Other critiques include the lack of space globally for the many proposed mass planting projects and the risk of competition between smallholder agriculture and planting.

Misclassification of grassland and wetland as suitable for forest and planting poorly adapted or cared-for seedlings have also been problems highlighted by scientists.