What did the researcher find?

Two social science concepts are of direct relevance. The first is "normal accidents". Zoonotic spillover is a relatively rare event, and although humans are continually exposed to many potentially infectious pathogens that are derived from other species, most of these microorganisms cannot infect or cause disease in humans. Pathogen spillover events can be linked with human-animal interactions with both natural hosts (such as bats) and intermediate hosts (such as domesticated animals). Although the risk posed by a single encounter or even several hundred encounters is quite low, the chance of spillover grows as the number of encounters grows. If encounters are frequent enough, spillover becomes “normal” – in the Anthropocene these encounters are growing rapidly – and in some cases exponentially.

Several human activities have already caused and elevate the risk of future zoonotic spillover, including climate change, hunting, human migration, landscape changes, livestock trade, and environmental contamination — and these threats have been accelerated with the process of globalization. "Treadmills" can emerge and pose a unique set of environmental threats to biodiversity and land system stability across a range of contexts. A “treadmill of production” is derived from and propels economic competition; a “treadmill of destruction” is fueled by geopolitical and military rivalries. Treadmills of production and destruction accelerate environmental degradation and heighten the risk of zoonotic spillover. The dangers posed by treadmills are istinctive because powerful organizations exploit nature and extract resources in competition with rivals that threaten their organizational vitality – and potentially their survival. These powerful organizations are caught on a treadmill of environmental degradation – and the pace of degradation quickens.