Scenarios: assessing alternative futures

Projecting possible outcomes for biodiversity under future scenarios of climate and land-use change

The challenge

There are a number of key drivers of ongoing change in biodiversity around the world, including climate change and land-use change. Biodiversity persistence under these drivers will be influenced by decisions societies make across local, to regional and global scales. Evaluating the potential effectiveness of alternative policy and management interventions aimed at addressing these impacts and promoting biodiversity persistence requires considering changes at sufficiently high resolution and across spatial scales for a broad representation of the Earth’s species.

Our response

BILBI can be harnessed to assess alternative future scenarios of land-use, climate change, and other drivers, enabling evaluation of the consequences of those alternative futures for biodiversity persistence. This includes directly incorporating the direct effects of continuing climate change on patterns in biodiversity as well as the effects of ongoing changes in human landuse on the capacity of landscapes to support biodiversity. BILBI can be used to explore the likely outcomes for biodiversity under future scenarios for regions, nations or the whole world.

Case-study: IPBES Global Scenario Assessment

The Expert Group on Scenarios and Models of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) recently carried out an intercomparison of biodiversity and ecosystem services models, using harmonized scenarios of land-use and climate change. As part of this international collaborative scenario assessment, BILBI was used to undertake a high-resolution (1 km), multi-extent (local to global) analysis of the expected changes in plant biodiversity persistence through space and time. This analysis found that ongoing landuse intensification combined with historic changes, are expected to lead to substantial species extinctions in the long term (~18,000 plant species globally), but that the expected level of species extinction increases dramatically (approximately four times greater) when that landuse change is coupled with ongoing climate change (Di Marco et al. 2019). This scenario assessment indicates that while reducing human impacts on natural systems is important, continued focus on mitigating anthropogenic climate change is potentially more important to support the persistence of biodiversity into the future.

Figure 1.  Spatial depiction of changes in expected biodiversity persistence (green = high; red = lower) from 1900 to 2050 under a shared socio-economic pathway (SSP) scenario.