Climate change may increase the risk of new infectious diseases

Climate change will lead to the spread of thousands of new viruses among animal species by 2070 – and this will likely 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 the spread of deadly diseases from humans to animals or vice versa in recent decades, including influenza, HIV, Ebola and the new coronavirus.

The researchers, who published their findings Thursday in the journal Natureused a model to examine how more than 3,000 species of mammals could migrate and share viruses over the next 50 years if the world warms by 2 C (3.6 F), which recent research shows is possible.

They found that cross-species spread of the virus will occur more than 4,000 times in mammals alone. Bats account for the majority of new viral shares. Birds and marine animals were not included in the study.

Implications for humans

The researchers said not all viruses will spread to humans or become pandemics on the scale of the new coronavirus, but the number of cross-species viruses increases the risk of spread to humans.

The study highlights two global crises – climate change and the spread of infectious diseases – as the world grapples with what to do about both.

By 2070, human population centers in equatorial Africa, southern China, India and Southeast Asia will overlap with projected hotspots of cross-species viral transmission in wildlife. (Colin Carlson/Georgetown University)

Previous research has looked at how deforestation, extinction, and the wildlife trade lead to the spread of animal and human disease, but there is less research on how climate change might influence this type of disease transmission. diseases, the researchers said at a press conference on Wednesday.

“We don’t talk a lot about climate in the context of zoonoses” – diseases that can spread from animals to humans, said study co-author Colin Carlson, an assistant professor of biology at Georgetown University. . “Our study…brings together the two most pressing global crises we have.”

Estimate is ‘extremely conservative’, says independent expert

Climate change and infectious disease experts have agreed that a warming planet will likely lead to an increased risk of new viruses emerging.

Daniel R. Brooks, biologist at the University of Nebraska State Museum and co-author of the book The Stockholm Paradigm: Climate Change and Emerging Diseasessaid the study recognizes the threat posed by climate change in terms of the growing risk of infectious diseases.

“This particular contribution is an extremely conservative estimate of the potential spread” of emerging infectious diseases caused by climate change, Brooks said.

Aaron Bernstein, pediatrician and acting director of the Center for Climate, Health and the Global Environment at Harvard TH Chan School of Public Health, said the study confirms long-held suspicions about the impact of warming on the emergence infectious diseases.

“Of particular note, the study indicates that these encounters may already be occurring with greater frequency and in locations close to where many people live,” Bernstein said.

Study co-author Gregory Albery, a disease ecologist at Georgetown University, said that as the emergence of climate-related infectious diseases is likely already happening, the world should do more. to learn more and prepare for it.

“It’s not avoidable, even under the best climate change scenarios,” Albery said.

Carlson, who was also the author of the latest Intergovernmental Panel on Climate Change report, said we need to reduce greenhouse gases and phase out fossil fuels to reduce the risk of spreading disease infectious.

Jaron Browne, organizing director of climate justice group Grassroots Global Justice Alliance, said the study highlights the climate injustices experienced by people living in African and Asian countries.

“African and Asian nations face the greatest threat of increased exposure to the virus, illustrating once again how those on the frontlines of the crisis have very often done the least to create climate change,” said Browne.