A new framework to predict the impacts of global socio-economic change on biodiversity

© 2021 Simon KapitzaBiodiversity in the anthropocene is under threat, but under current trajectories of socio-economic development it is unlikely that current targets to halt the decline of biodiversity will be met. Climate change, sea/land-use change, pollution, direct exploitation of organisms and the invasion of alien species continue to directly drive global biodiversity change, with significant adverse impacts on species and ecosys- tems. These drivers are themselves driven by global patterns in the consumption and production of economic commodities, trade, governance, human population trends, and technological innovations. To better protect biodiversity, it is necessary to reduce uncertainty around future biodiversity change and to clearly delineate how changes may manifest themselves throughout the 21st century. Accordingly, the integration biodiversity models with models from socio-economic (and other) disciplines is critical for accurate representations of linkage between human and natural systems driving biodiversity change. However, established integrated assessment models are highly complex and typi- cally not designed for biodiversity assessments. Streamlined frameworks that can be used quickly by ecologists remain very rare and new methods are sorely needed to make integrated biodiversity modelling accessible to a wide range of applications. To fill this gap, this thesis innovates a new integrated modelling framework for bio- diversity assessments, coupling macro-economic, land-use and biodiversity modelling power. Our framework capitalizes on recent advances in computable general equilib- rium (CGE) modelling, bringing unprecedented power to parametrize the impacts of various socio-economic impacts and climate change on global commodity consumption and production patterns at very high commodity and temporal resolutions. Land-use changes caused by changes in the consumption and production of agricultural com- modities are spatially downscaled and resulting predicted land-use maps serve as input for biodiversity models. Chapter 2 provides the initial roll-out of our integrated assessment framework to quantify the relative influence of direct biophysical and indirect socio-economic (via commodity demand and land-use change) climate change impacts on bird species in Vietnam and Australia. In this chapter, we spatially downscale projected changes in commodity demand, using an existing categorical land-use model with limited appli- cability. Chapter 3 introduces and validates a new land-use model to interface global com- modity demand projections and biodiversity change. The model enables the fine-scale mapping of future land-use change under alternative scenarios of commodity demand change. It represents land-use as fractional cover within grid cells, thus providing higher information content than discrete categories of land-use, without the need to de- crease the spatial resolution. The model allows us to upscale the modelling framework to the global extent and to better align land-use predictions with the requirements of global-scale biodiversity modelling. Chapter 4 presents a first global implementation of our framework to predict global biodiversity under shared socio-economic scenarios. We use the land-use model devel- oped in Chapter 3 to spatially downscale commodity demand change expected under two socio-economic scenarios also commonly applied in other disciplines, and compare predictions made using our streamlined framework against predictions made using a highly complex integrated assessment model. We contribute an open and streamlined method to model socio-economic impacts on biodiversity, bringing integrated assessments of biodiversity change within reach of ecologists. The work presented here demonstrates that we are now capable of success- ful applications under a wide range of scenarios and highlights where developments are necessary to further improve our framework’s relevance to support global biodiversity policy