“We have demonstrated a novel and potentially devastating mechanism for disease emergence that could threaten the health of animals in the future and will likely have ramifications for us, too,” Gregory Albery, an expert in disease ecology at Georgetown University and co-author of the study, told The Guardian.
“As the world changes, the face of disease will change too,” Albery said. “This work provides more incontrovertible evidence that the coming decades will not only be hotter, but sicker.”
Their report, published in Nature on Thursday, warns that “climate and land use change will produce novel opportunities for viral sharing among previously geographically-isolated species of wildlife. In some cases, this will facilitate zoonotic spillover - a mechanistic link between global environmental change and disease emergence.”
In their study, the scientists attempted to anticipate how some 3,139 mammal species would react to a warming climate, including migrating to higher terrain where the air is cooler and congregating together in new ways. In fact, this dynamic is already beginning to unfold.
“There is this monumental and mostly unobserved change happening within ecosystems,” Colin Carlson, another co-author, told the Guardian. “We aren’t keeping an eye on them and it makes pandemic risk everyone’s problem. Climate change is creating innumerable hotspots for zoonotic risk right in our backyard. We have to build health systems that are ready for that.”
Another aspect of a warming planet - thawing permafrost - also threatens to unleash ancient pathogens as animals whose carcasses have been preserved in the frozen ground become exposed. Other dynamics driving increased zoonotic transmission, such as deforestation and urbanization, have been studied in the past.
While finding the origin of a disease can be nigh-impossible, many epidemic diseases that have plagued humanity are believed to have originally been spread among other animals first, including Human Immunodeficiency Virus (HIV), bubonic plague, ebola, and SARS-CoV-2, the virus that causes COVID-19. Some also come solely from infection by host animals, like African sleeping sickness, malaria, and dengue fever, which can reach epidemic levels of infection.