A large multi-model study published in Science has revealed that global biodiversity declined between 2% and 11% during the 20th century due to land-use change alone. The projections also show that climate change could become the main driver of biodiversity decline by the mid-21st century.
Largest Modeling Study of Its Kind
An international team of researchers, led by the German Centre for Integrative Biodiversity Research (iDiv) and the Martin Luther University Halle-Wittenberg (MLU), modeled the impacts of land-use change on biodiversity over the 20th century. They compared thirteen models for assessing the impact of land-use change and climate change on four distinct biodiversity metrics and nine ecosystem services.
“By including all world regions in our model, we were able to fill many blind spots and address criticism of other approaches working with fragmented and potentially biased data,” says first author Henrique Pereira, research group head at iDiv and MLU. “Every approach has its ups and downsides. We believe our modeling approach provides the most comprehensive estimate of biodiversity trends worldwide.”
Climate Change Poses Imminent Threat to Biodiversity and Ecosystem Services
The researchers also examined how biodiversity and ecosystem services might evolve in the future, adding climate change as a driver of biodiversity change to their calculations. They found that climate change poses an imminent threat to biodiversity and ecosystem services, potentially overtaking land-use change as the primary driver of biodiversity loss by mid-century.
The team evaluated three commonly used scenarios and found that regardless of the scenario, the combined effects of land-use change and climate change lead to biodiversity loss across all global regions. While the overall downward trend is consistent, there are considerable variations across world regions, models, and scenarios.
The authors emphasize that the purpose of long-term scenarios is not to predict what will happen, but rather to understand alternatives and avoid the least desirable trajectories. Trajectories depend on the policies chosen, and these decisions are made day by day.
“Our analysis shows that a truly integrated approach considering the different sustainability dimensions in a consistent framework is needed to reduce conflicts between policies and safeguard biodiversity in the coming decades,” notes IIASA Biodiversity and Natural Resources Program Director Petr Havlík, one of the study coauthors.
The findings clearly show that current policies are insufficient to meet international biodiversity goals, emphasizing the need for renewed efforts to make progress against one of the world’s largest problems – human-caused biodiversity change.
Pereira, H.M., Martins, I.S., Rosa, I.M.D., Kim, H., Leadley, P., Popp, A., van Vuuren, D.P., Hurtt, G., et al. (2024). Global trends and scenarios for terrestrial biodiversity and ecosystem services from 1900-2050. Science DOI: 10.1126/science.adn3441