Climate change will cause thousands of new viruses to spread between animal species, increasing the risk that new diseases will infect humans, potentially setting off another pandemic, a study published Thursday in Nature finds. At least 10,000 viruses are capable of infecting humans but the vast majority are circulating only among wild animals. Over the next 50 years, with 2°C (3.6°F) of warming above preindustrial levels, researchers found cross-species virus spread — among mammals alone — would occur more than 4,000 times. The increased risk of what scientists call ‘zoonotic spillover’ from wild animals to humans will be caused by warming temperatures forcing animals to migrate to new regions and habitats as well as increased human intrusion into, and destruction of, animal habitat.

Human activity, especially the extraction and combustion of fossil fuels, has already heated global temperatures to an average of 1°C (2.7F) above preindustrial levels and will limit warming to under 2°C — if current emissions reduction pledges are achieved. (Zoonotic Spillover: New York Times $, AP, Gizmodo, Grist, FT $, The Hill, Al Jazeera, ABC, Daily Beast, MSNBC, The Independent, CNBC; Climate Signals background: Vector-borne disease risk increase)