“The coming decades will not only be hotter but sicker.” In a new study, researchers say global warming will cause thousands of new viruses to spread between species by 2070 and create pandemics. Africa and Asia are particularly affected, but as the planet warms up, the areas at risk are multiplying, particularly in Europe.
This is an alarming study that has just been published in the prestigious journal Nature. Researchers from Georgetown University have carried out a comprehensive assessment of how climate change is impacting virus transmission between animal species. And the conclusion is clear: climate change will become in the years to come the greatest risk factor for the emergence of diseases, ahead of deforestation, the trade in wild species or industrial agriculture. Scientists estimate that by 2070, at least 15,000 interspecies transmissions should occur if the planet warms by +2°C. However, this trajectory is already optimistic since, according to a new study, we have a one in two chance of not exceeding 2°C of warming by 2100 if the commitments made by governments around the world are kept.
To reach these conclusions, the researchers analyzed the potential displacement of mammals according to climate change. The latter will indeed migrate in search of livable habitat and food in areas where they would not have gone so far. While migrating, these mammals carry diseases and come across other host animals which can themselves transmit these diseases to humans, what specialists call zoonoses. “As the world changes, so will the face of disease.“, explains Gregory Albery, disease ecologist at Georgetown University and co-author of the study. “This work provides compelling evidence that the coming decades will not only be warmer but sicker.”
Hotspots all over the world
Scientists have identified “hotspots”, particularly high-risk areas that could lead to the emergence of zoonoses. The Sahel region in North Africa, the Ethiopian highlands, eastern China and the Philippines are hotspots pointed out by researchers. But some regions of Europe are also affected. The more the Earth warms up, the more the “hotspots” multiply. A process already underway with warming today limited to +1.2°C.
“We don’t monitor hotspots and that makes pandemic risk everyone’s problem. Climate change is creating countless hotspots for zoonotic risk right in our backyards. We need to build health systems that are ready for it“, advances Gregory Albery in The Guardian. For the authors of the study, the solution is to couple the surveillance of wildlife diseases with real-time studies of environmental changes.
The bat in the viewfinder
“When a Brazilian free-tailed bat travels to Appalachia, we should try hard to find out what viruses accompany it”says Colin Carlson, assistant research professor at the Center for Global Health Science and Security at Georgetown University Medical Center. “Trying to spot these “host jumps” in real time is the only way to prevent this process from leading to more spillovers (the passage of a virus from a wild animal to the human population, NDR) and to more of pandemics.” The example of bats is not trivial since the latter, due to “of their central role in viral emergence”for their ability to fly great distances, are particularly feared.
After two years of research, the Institut Pasteur also claims to have found coronaviruses close to Covid-19, a virus which triggered a pandemic and killed more than 6 million people worldwide, in the Laos bat. Last year, IPBES, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, the equivalent of the IPCC for biodiversity, calculated that of the 1.7 million undiscovered viruses currently present in mammals and birds, 827,000 might have the ability to infect humans.