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Reforestation may not be sufficient for fighting climate change
Could the Earth carry a quarter more forest? Researchers at the University of Bonn and World Agroforestry consider this estimate far too high.

Nairobi, Kenya, 18 October 2019 — In early July, a study in Science made global headlines: Earth could carry 4.4 billion hectares of canopy cover, which is 900 million more than today. Through reforestation, 205 gigatons of carbon could be removed from the atmosphere and climate change effectively slowed down. Scientists at the University of Bonn and World Agroforestry consider these figures strongly inflated: they argue that these numbers are based on highly simplified or questionable assumptions. Their response letter was released on 18th October, also in Science.

The original study is based on a simulation by scientists from ETH Zurich, who had investigated how much forest the Earth could theoretically support in areas not currently inhabited or managed by humans. For this, they had looked at nature reserves around the globe, that is, regions that are largely free from human influence.