When farmland is abandoned and allowed to return to nature, forests and grasslands naturally regrow and absorb carbon dioxide from the atmosphere—helping fight climate change. However, a new study led by scientists at Columbia University, reveals an important wrinkle in this story: these regenerating ecosystems also release other greenhouse gases that reduce some of their climate benefits. The good news? Even accounting for these other gases, letting land regenerate naturally still provides important climate benefits compared with keeping it in agriculture. 

• Regenerating forests typically absorb small amounts of methane but release enough nitrous oxide to create a net warming effect from these two gases combined
• Carbon dioxide absorbed by growing trees far outweighs this warming effect in most ecosystems—even after 100 years
• Natural ecosystems produce much lower greenhouse gas emissions than agricultural land, showing the clear climate benefit of forest regeneration