In 2019, Carlson and a colleague created a massive simulation that maps the past, present, and future ranges of 3,100 mammal species, and predicts the likelihood of viral spillovers if those ranges overlap. Even under the optimistic climate scenarios, Carlson estimates that the coming decades will see about 300,000 first encounters between species that normally don’t interact, leading to roughly 15,000 spillovers in which viruses enter new hosts.
