The researchers explained that rising temperatures may force animals into closer proximity to humans; this is likely to increase the number of viruses spread from animals to humans, which could incite the next pandemic.
“The closest analogy is actually the risks we see in the wildlife trade,” said researcher Colin Carlson, Ph.D. “We worry about markets because bringing unhealthy animals together in unnatural combinations creates opportunities for this stepwise process of emergency – like how SARS jumped from bats to civets, then civets to people. But markets aren’t special anymore; in a changing climate, that kind of process will be the reality in nature just about everywhere.”
Long-term risks to human health
For the study, the researchers analyzed projected geographic range shifts for over 3,100 mammal species based on climate change predictions by the year 2070. The team was most interested in understanding how changes to the global temperature will affect where animals live and how that will affect the spread of viruses.
The study showed that as the global temperature continues to rise, animals are going to be forced to move into areas that are heavily populated by humans. The researchers predict that Asia and Africa are likely to be the hotspots for this trend. The team also anticipates that the number of animal-borne infections is likely to increase by 4,000 times.
“At every step, our simulations have taken us by surprise,” Dr. Carlson said. “We’ve spent years double-checking those results, with different data and different assumptions, but the models always lead us to these conclusions. It’s a really stunning example of how well we can, actually, predict the future if we try.”
The team's work found that bats may be the biggest culprits of this disease spread. Because bats can travel long distances, they are the most likely to contribute to the rapid spread of infections.
The researchers explained that the biggest risks are to human health and environmental conservation. This is likely to increase the likelihood that viruses like Ebola and COVID-19 are more prevalent around the world. Moving forward, the team hopes to be able to conduct more research on both the impact of climate change on animal relocation and the monitoring of animal-borne infections.
“When a Brazilian free-tailed bat makes it all the way to Appalachia, we should be invested in knowing what viruses are tagging along,” said Dr. Carlson. “Trying to spot these host jumps in real-time is the only way we’ll be able to prevent this process from leading to more spillovers and more pandemics.
“We’re closer to predicting and preventing the next pandemic than ever. This is a big step towards prediction – now we have to start working on the harder half of the problem.”