Climate Change Could Spark Future Pandemics, Study Finds

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Global warming could fuel future pandemics by dramatically increasing the risk viruses will jump into humans from other animals, researchers warned Thursday, illuminating another hidden and far-reaching cost of the climate crisis.

Spillover events between species, especially bats, are more likely as temperatures increase, … [+] researchers warned.

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Key Facts

As the world gets warmer, many animals will be forced to find new places to live, taking any parasites and pathogens they carry along for the ride, researchers wrote in Nature.

The researchers examined how climate change could alter the geographic range of some 3,100 mammal species between now and 2070 and how this might affect the transmission of viruses between species.

Even under the most optimistic climate forecasts—less than 2°C warming—the researchers predict climate change will trigger at least 15,000 new instances of viruses crossing between species for the first time by 2070.

The researchers said these “spillover” events will be predominantly driven by bats—which can travel large distances, are likely to carry pathogens capable of infecting humans and are widely believed to be the source of Covid-19—and concentrated in densely populated areas in Asia and Africa.

While it’s not clear precisely how the new viruses will affect species involved, Dr. Gregory Albery, one of the study’s lead authors and a disease ecologist at Georgetown University, said it is “likely” many will “fuel the emergency of novel outbreaks in humans.”

With human activity driving temperatures upwards, this process could already be well underway, the researchers warned, adding that efforts to cut greenhouse gas emissions may not be enough to stave off the increased transmission of viruses between species.

Tangent

Viruses jumping between different species can also have a dramatic impact on wildlife and conservation, the researchers warned. They pointed to nearly 3,700 different animals that could encounter the 13 species known to harbor Ebola virus for the first time due to climate change. Beyond humans, Ebola has torn through primate populations with devastating effect, notably endangered gorillas. The researchers said it would be valuable to study other animals in future work, particularly amphibians—which are already battling a fungal plague that has wiped out at least 90 species—and marine mammals. It will also be important to understand the impact of climate change on birds and the pathogens they carry, the researchers said. Besides mammals, the viral ecosystem of birds is the most well-documented and accounts for the most viruses capable of crossing over into humans.

Big Number

10,000. That’s how many viruses capable of infecting humans there are, the researchers said. The vast majority of these are “silently” circulating in wild mammals. Spillover events are usually rare, though they have become more frequent as issues like habitat destruction, the wildlife trade and industrialized agriculture bring animals into closer contact with humans.

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