Climate change will result in thousands of new viruses spreading among animal species by 2070 and that's likely to increase the risk of emerging infectious diseases jumping from animals to humans, according to a new study.
This is especially true for Africa and Asia, continents that have been hotspots for deadly disease spread from humans to animals or vice versa over the last several decades, including the flu, HIV, Ebola and COVID-19.
Researchers, who published their findings on Thursday in the journal Nature, used a model to examine how over 3,000 mammal species might migrate and share viruses over the next 50 years if the world warms by 2C.
They found that cross-species virus spread will happen over 4,000 times among mammals alone. Birds and marine animals weren't included in the study.
The risk of future pandemics because of climate change
Researchers said not all viruses will spread to humans or become pandemics the scale of the COVID-19, but the number of cross-species viruses increases the risk of spread to humans.
As viruses start to jump between host species at unprecedented rates, the authors say that the impacts on conservation and human health could be stunning.
“This mechanism adds yet another layer to how climate change will threaten human and animal health,” said the study’s co-lead author Gregory Albery, a postdoctoral fellow in the Department of Biology at Georgetown University.
“It’s unclear exactly how these new viruses might affect the species involved, but it’s likely that many of them will translate to new conservation risks and fuel the emergence of novel outbreaks in humans.”
He added: “It is not preventable, even in the best case climate change scenarios.”
Albery also warned that because climate-driven infectious disease emergence is likely already happening, the world should be doing more to learn about and prepare for it.
Previous research has looked at how deforestation, extinction and the wildlife trade lead to animal-human disease spread, but there's less research about how climate change could influence this type of disease transmission, the researchers said at a media briefing on Wednesday.
The need to limit global warming as much as possible
Study co-author Colin Carlson, who was also an author on the latest report from the Intergovernmental Panel on Climate Change, said we must cut greenhouse gas and phase out fossil fuels to reduce the risk of infectious disease spread.
Jaron Browne, organising director of the climate justice group Grassroots Global Justice Alliance, said the study highlights climate injustices experienced by people living in African and Asian nations.
“African and Asian nations face the greatest threat of increased virus exposure, once again illustrating how those on the frontlines of the crisis have very often done the least to create climate change," Browne said.