Reforestation boosts biodiversity, while other land-based climate mitigation strategies fall short

Reforestation is a win-win for climate and wildlife, but large-scale afforestation and bioenergy cropping may do more harm than good, according to a new study of land-based climate mitigation strategies (LBMS) for over 14,000 species. The findings emphasize the need to ensure well-intentioned climate action does not exacerbate biodiversity loss. While reducing greenhouse gas emissions is critical, increasing atmospheric carbon removal is equally essential to effectively combat climate change. LBMS considered among the most scalable and nature-based carbon removal solutions include reforestation (restoring forests in historically forested areas), afforestation (introducing forests in previously unforested areas), and bioenergy cropping for carbon capture and storage. However, these approaches also have the potential to alter vast areas of land and habitat, raising concerns about their potential impacts on global biodiversity. Jeffrey Smith and colleagues modeled the habitat and climate needs of over 14,234 globally distributed vertebrate species to evaluate these effects. They found that reforestation offers a clear net benefit to global biodiversity by simultaneously mitigating climate change and expanding habitats for numerous species. Conversely, afforestation and bioenergy cropping often harm biodiversity, as their habitat conversion impacts typically outweigh any gains from climate stabilization. Thus, the local habitat disruptions caused by these land-based climate mitigation strategies generally have a more pronounced effect on biodiversity than their global climate benefits. According to the authors, the findings challenge the assumption that LBMS inherently benefit biodiversity by curbing climate change and underscore the importance of integrating local ecological insights into LBMS planning to predict biodiversity outcomes accurately and prevent making the biodiversity crisis worse, while also addressing climate change.

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