Study: Climate Change Could Spark Next Pandemic

As viruses start to jump between host species at unprecedented rates, the researchers say the impacts on human health could be "stunning."

Planet Earth viewed from space with city lights in Europe. World with sunrise. Conceptual image for global business or European communication technology, elements from NASA

Washington, D.C.— Researchers who led a comprehensive study published in Nature determined that animal migration and rising temperatures may cause virus spread to new areas, potentially to humans. The study suggests that the climate crisis had an impact on human health, and the greatest risk factor for another pandemic is climate change. It surpassed factors like deforestation, agriculture, and wildlife trade.

The international team of researchers, led by scientists at Georgetown University, found that climate change-related animal migration was linked to Ebola and coronaviruses. They noted that viruses will be harder to track with the infection of new species in greater locations. This will cause higher rates of human exposure. Additionally, thousands of viruses will be shared among wild animals.

“The closest analogy is actually the risks we see in the wildlife trade,” said lead author Colin Carlson, Ph.D., an assistant research professor at the Center for Global Health Science and Security. “We worry about markets because bringing unhealthy animals together in unnatural combinations creates opportunities for this stepwise process of emergence—like how SARS jumped from bats to civets, then civets to people. But markets aren’t special anymore; in a changing climate, that kind of process will be the reality in nature just about everywhere.”

Animal ecosystem migration to human locations will create virus hotspots. This has already begun, with temperatures 1.2 degrees warmer world-wide. Data reflected rising temperatures’ impact on bats, whose travel capacities allow greater spread. One predicted hotspot included Southeast Asia, for this reason.

“At every step,” said Dr. Carlson, “our simulations have taken us by surprise. We’ve spent years double-checking those results, with different data and different assumptions. The models always lead us to these conclusions. It’s a really stunning example of just how well we can, actually, predict the future if we try.”

The impact of climate change on human health could be significant, as viruses transfer at new rates. “This mechanism adds yet another layer to how climate change will threaten human and animal health,” said co-lead study author, Gregory Albery, Ph.D., a postdoctoral fellow in the Department of Biology. “It’s unclear exactly how these new viruses might affect the species involved. It’s likely that many of them will translate to new conservation risks and fuel the emergence of novel outbreaks in humans.”

A possible solution: further research on species infected and their migration patterns. “When a Brazilian free-tailed bat makes it all the way to Appalachia, we should be invested in knowing what viruses are tagging along,” said Dr. Carlson. “Trying to spot these host jumps in real-time is the only way we’ll be able to prevent this process from leading to more spillovers and more pandemics.”

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Overall, researchers believe this study will help mitigation efforts and lead to greater understanding of pandemic prevention. Dr. Carlson said, “We’re closer to predicting and preventing the next pandemic than ever. This is a big step towards prediction—now we have to start working on the harder half of the problem.”

In conclusion: “The COVID-19 pandemic, and the previous spread of SARS, Ebola, and Zika, show how a virus jumping from animals to humans can have massive effects,” said Sam Scheiner, a program director with the U.S. National Science Foundation, which funded the research. “To predict their jump to humans, we need to know about their spread among other animals. This research shows how animal movements and interactions due to a warming climate might increase the number of viruses jumping between species.”