Probable hotspots include the Sahel, the Ethiopian Mountains, the Rift Valley, India, East China, Indonesia and the Philippines.
Climate change will lead animals to cooler areas, where their first encounters with other species will significantly increase the risk of new viruses infecting humans, researchers warned on Thursday.
There are currently at least 10,000 viruses that “circulate silently” among wild mammals, which have the ability to pass into humans, mostly in the depths of tropical forests.
As rising temperatures force these mammals to abandon their native habitats, they will encounter other species for the first time, creating at least 15,000 new cases of viruses hovering between animals by 2070, according to a study published in the journal Nature.
“We have demonstrated a new and potentially devastating disease mechanism that could threaten the health of animal populations in the future, which is likely to have consequences for our health,” said study co-author Gregory Alberry, a disease ecologist in Georgetown. University.
“This work provides us with more conclusive evidence that the coming decades will not only be hotter, but also sicker,” Albury said.
The five-year study looked at 3,139 mammalian species, modeling how their movements would change in a number of global warming scenarios, and then analyzing how viral transmission would be affected.
The researchers found that new contacts between different mammals would effectively double, with the first encounters occurring around the world, but especially concentrated in tropical Africa and Southeast Asia.
The threat of bats
Global warming will also lead to these first contacts in more densely populated areas, where people are “likely to be vulnerable and some viruses will be able to spread globally from each of these settlements,” according to the study.
Probable hotspots include the Sahel, the Ethiopian Mountains and the Rift Valley, India, eastern China, Indonesia, the Philippines and some European cities, the study found.
The study ended just weeks before the coronavirus pandemic began, but highlighted the unique threat posed by bats, which are believed to have first appeared COVID-19. As the only mammal that can fly, bats can travel far longer distances than their land-related brethren, spreading disease as they move.
Bats are thought to be on the move, and research has found that they represent a large part of potential first encounters with other mammals, particularly in Southeast Asia.
Even if the world makes massive and rapid reductions in greenhouse gas emissions – a scenario that still seems quite far away – this may not help with this problem.
Modeling has shown that the mildest climate change scenarios can lead to more transmission between species from the worst-case scenarios, as slower warming gives animals more time to travel.
“Inevitable”
Researchers have also tried to figure out when the first encounters between species may begin, expecting it to be later this century.
But “surprisingly” their forecasts found that most of the first contacts will be between 2011 and 2040, and from there they are constantly increasing.
“It happens. “This is unavoidable even in the best-case scenario for climate change, and we need to put in place measures to build health infrastructure to protect animal and human populations,” Albury said.
Researchers point out that while focusing on mammals, other animals may contain zoonotic viruses – the name of viruses that jump from animals to humans.
They called for further research into the threat posed by birds, amphibians and even marine mammals, as the melting of sea ice allows them to mix more.
Co-author Colin Carlson, a global change biologist also in Georgetown, said climate change “creates countless hotspots of future zoonotic risk – or today’s zoonotic risk – right in our backyard.”
“We need to recognize that climate change will be the biggest driver of disease,” Carlson said, “and we need to build health systems that are ready for that.”
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