COS 96-3 - Nature based climate solutions may – or may not – safeguard biodiversity

Abstract: Nature-based solutions [NBS] to climate change have emerged in both the scientific community and broader public as a potential way to address two of humanity’s biggest challenges, climate change and biodiversity loss. Such solutions are heralded for their ability to make a significant dent in the global carbon budget, providing 1/3^rd of the necessary reduction in emissions by the year 2030 to meet the goals of the Paris Climate Accord. They have been widely adopted by both conservation groups as well as for-profit companies and it is often assumed that many NBS will be beneficial to biodiversity locally or that, at least, the benefits of climate stabilization achieved by their use will offset any locally detrimental effects on biodiversity. However, recent research has questioned the efficacy of attaching biodiversity conservation to the goals of climate-focused NBS. It is therefore clear that we need a unified understanding of how NBS will affect biodiversity – both directly by changing the landscape of habitats that species can occupy and indirectly by moderating the climate system.



In this presentation we quantify the direct and indirect effects of the three NBS, reforestation, aforestation and bioenergy, on global vertebrate diversity. By quantifying these impacts for 25,000 species we put forward to the first estimates of how various NBS will affect biodiversity globally. We find strong evidence that addressing climate change will be beneficial to the majority of species globally (62.9% of amphibians, 74.6% of birds, 55.9% of mammals, and 56.9% of reptiles). When considering the effects of local land-use change we find that reforestation efforts are generally positive (66.5% - 70.1% of species) while the effects of afforestation are mixed, and the effects of bioenergy are generally negative (61.0% - 71.9% of species). Win-win scenarios, where species are most likely to be benefitted by both climate stabilization impacts are most common under reforestation. We further found that the greatest impacts were likely to be realized in tropical regions. From a land-use change perspective this is driven by the latitudinal gradient in species richness – where habitat gains or losses in the tropics act on a far greater number of species. From a climate perspective this is driven by the greater carbon uptake potential of tropical plants relative to their temperature or boreal counterparts. Overall, our results provide a number of concise, and data-supported, best practices that practitioners can use to guide the deployment of NBS.