PARIS: Climate change will drive animals towards cooler areas where their first encounters with other species will vastly increase the risk of new viruses infecting humans, raising the threat of another pandemic, researchers warned on Thursday.

There are currently at least 10,000 viruses that have the capacity to cross over into humans “circulating silently” among wild mammals, mostly in the depths of tropical forests, according to a study published in the Nature journal.

But as rising temperatures force those mammals to abandon their native habitats, they will meet other species for the first time, creating at least 15,000 new instances of viruses jumping between animals by 2070, the study forecasted.

This process has likely already begun, will continue even if the world acts quickly to reduce carbon emissions and poses a major threat to both animals and humans, the researchers said.

“We have demonstrated a novel and potentially devastating mechanism for disease emergence that could threaten the health of animal populations in the future, which will most likely have ramifications for our health too,” said study co-author Gregory Albery, a disease ecologist at Georgetown University.

“This work provides us with more incontrovertible evidence that the coming decades will not only be hotter, but sicker,” Albery said.

The study, five years in the making, looked at 3,139 species of mammals, modelling how their movements would change under a range of global warming scenarios, then analysing how viral transmission would be affected.

They found that new contacts between different mammals would effectively double, with first encounters occurring everywhere in the world, but particularly concentrated in tropical Africa and Southeast Asia.

Global warming will also cause those first contacts to take place in more highly populated areas, where people “are likely to be vulnerable, and some viruses will be able to spread globally from any of these population centres”.

Likely hotspots include the Sahel, the Ethiopian highlands and the Rift Valley, India, eastern China, Indonesia, the Philippines and some European population centres, the study found.

The research was completed just weeks before the start of the coronavirus pandemic, but emphasised the unique threat posed by bats, in which Covid is believed to have first emerged.

As the only mammal that can fly, bats can travel far greater distances than their land-bound brethren, spreading disease as they go.

Bats are believed to already be on the move, and the study found they accounted for a large majority of potential first encounters with other mammals, mostly in Southeast Asia.

Published in Dawn, April 29th, 2022