The immediate impacts of climate change and land-use change are severe enough, but increasingly, researchers are warning that large enough changes can then snowball into catastrophic changes. New, supercomputer-powered research from Giovanni Strona (a senior researcher with the European Commission’s Joint Research Centre, or JRC) and Corey Bradshaw (a professor at Flinders University in Australia) shows how devastating that effect may be, with simulations showing double-digit percentage losses in vertebrate species diversity by the end of the century.

“The planet has entered the sixth mass extinction,” the paper opens, explaining how land-use change, overharvesting, pollution, climate change and invasive species have emerged as “dominant processes” in the extinction of species. In their research, the authors focused specifically on coextinction – “the loss of species caused by direct or indirect effects stemming from other extinctions.”

“Previous attempts to predict the future of global diversity in the face of climate change and habitat modification have only considered the direct effects of these drivers on species (typically on single taxonomic groups), without explicitly accounting for ecological interactions,” they explain.

To help address this gap in the research, the authors developed a “complex and ecologically realistic dynamic model” to represent terrestrial vertebrate communities, using that model to project future biodiversity trends through 2100 at a monthly temporal scale and a 1°-square spatial scale (and under a variety of climate and land-use scenarios).

Running a model like that is, of course, no small feat, and the researchers turned to European supercomputing to carry the computational load – specifically, the Puhti system at CSC in Finland. Puhti, launched in 2019, has 682 CPU nodes powered by dual Intel Xeon “Cascade Lake” CPUs, summing to some 1.8 peak petaflops. (CSC now, of course, hosts the massive LUMI system, which was not available at the time of the research.) The researchers told HPCwire that they used about 2,000 CPU-days to run the model on Puhti.

The startling result: a predicted 17.6% average reduction of local vertebrate diversity globally by the end of the century, with lower-end projections landing around 13.0% and the even more disastrous projections landing at a staggering 27.0% loss of diversity. Interestingly – and worryingly – the plurality of this loss was concentrated in the next few decades, with loss estimates for 2050 ranging from 6.0% to 10.8%.

“Our results confirm that coextinctions are fundamental drivers of mass extinctions and suggest that previous large extinction events revealed from the fossil record would likely have been exacerbated beyond their primary environmental drivers via the negative feedbacks arising from ecological dependencies,” the authors conclude. “Unless conservation practitioners rapidly start to incorporate the complexity of ecological interactions and their role in extinction processes in their planning, averting the ongoing biodiversity crisis will become an unachievable target.”

To learn more about this research, read the paper here.