Ten degree change sufficient for total annihilation of life on Earth

Simulation study shows that co-extinctions can amplify effects of extreme environmental change by up to ten times

Data resources used via GBIF : 7,219,298 species occurrences
Ursus maritimus
Polar bear (Ursus maritimus) observed by tas47. Photo via iNaturalist (CC BY-NC 4.0)

Numerous studies have shown how climate change and human activities can have detrimental effects on biodiversity, eventually leading to extinctions. When one species disappears, it affects all its ecological dependencies and further co-extinctions can occur, possibly causing extinction cascades and eventually, total collapse of an ecosystem.

In an elaborate simulation study, researchers created 2,000 "virtual Earths", populated them with virtual terrestrial species each with their own environmental tolerances calibrated using GBIF-mediated occurrences, arranged into structured food webs. The authors then exposed the virtual planets to continuous, progressive changes in temperature (heating and cooling), and while allowing for some dispersal and adaptation, ran the simulations until temperature had changed by 50° celcius.

Considering environmental tolerances only, the authors show that a global warming of 10° would lead to the extinction of more than 60 per cent of species. For 10° cooling, fewer than 20 per cent of species would remain. However, in both scenarios, if including effects of co-extinctions, a 10° change would be sufficient for total annihilation of all life.

Link to original article

Strona G and Bradshaw CJA (2018) Co-extinctions annihilate planetary life during extreme environmental change. Scientific Reports. Springer Nature 8(1). Available at: https://doi.org/10.1038/s41598-018-35068-1.