Climate change will lead animals to colder areas where their first encounters with other species will significantly increase the risk of new viruses infecting humans, researchers warned on Thursday. Currently, there are at least 10,000 viruses “circulating silently” among wild mammals that have the ability to pass into humans, especially in the depths of tropical forests. As rising temperatures force these mammals to leave their native habitats, they will encounter other species for the first time, creating at least 15,000 new cases of viruses that jump between animals by 2070, according to a study published in the journal Nature. “We have demonstrated a new and potentially catastrophic mechanism for the emergence of diseases that could threaten the health of animal populations in the future, which is likely to have an impact on our health,” said study co-author Gregory Albery, a disease ecologist. in Georgetown. University. “This project provides us with more indisputable evidence that the coming decades will not only be hotter, but also sicker,” Albury said. The five-year study looked at 3,139 species of mammals, modeling how their movements would change under a series of global warming scenarios and then analyzing how the virus would be transmitted. The researchers found that new contacts between different mammals would substantially double, with the first encounters occurring around the world, but particularly concentrated in tropical Africa and Southeast Asia.
The threat of bats
Global warming will also cause these first contacts to take place in more densely populated areas, where people “are likely to be vulnerable and some viruses could spread globally from any of these population centers,” according to the study. Possible hot spots include the Sahel, the Ethiopian Highlands and the Rift Valley, India, eastern China, Indonesia, the Philippines and some European population centers, according to the study. The research was completed a few weeks before the onset of the coronavirus pandemic, but highlighted the only threat posed by bats, in which COVID-19 is believed to have first appeared. As the only mammal that can fly, bats can travel far greater distances than their siblings on land, transmitting diseases as they progress. The bats are believed to be already in motion and the study found that they accounted for the vast majority of possible first encounters with other mammals, mainly in Southeast Asia. Even if people cut greenhouse gas emissions quickly and massively – a scenario that still seems a bit far-fetched – it may not help. The modeling showed that milder climate change scenarios could lead to greater species-specific transmission than the worst-case scenarios, because slower heating gives animals more time to travel.
“It can not be prevented”
The researchers also tried to find out when the first encounters between species could begin to occur, expecting it to be later this century. But “surprisingly” their forecasts found that most of the first contacts would be between 2011 and 2040, steadily increasing from there. “This is happening. It cannot be avoided even in the best of climate change scenarios and we must take steps to build health infrastructure to protect animal and human populations,” Albury said. The researchers said that while they focused on mammals, other animals could harbor zoonotic viruses – the name for viruses that are passed from animals to humans. They called for further research on the threat posed by birds, amphibians and even marine mammals, as the melting of sea ice allows them to mix more. Study co-author Colin Carlson, a global change biologist also at Georgetown, said climate change “creates innumerable hot spots of future zoonotic risk – or current zoonotic risk – right in our backyard.” “We need to recognize that climate change is going to be the biggest driver of disease,” said Carlson, “and we need to build health systems that are ready for that.”
