Climate Will Bring More Novel Diseases

May 2, 2022


At least 10,000 virus species have the capacity to infect humans, but at present, the vast majority are circulating silently in wild mammals1,2. However, climate and land use change will produce novel opportunities for viral sharing among previously geographically-isolated species of wildlife3,4. In some cases, this will facilitate zoonotic spillover—a mechanistic link between global environmental change and disease emergence.

New York Times:

Over the next 50 years, climate change will drive thousands of viruses to jump from one species of mammal to another, according to a study published in Nature on Thursday. The shuffling of viruses among animals may increase the risk that one will jump into humans and cause a new pandemic, the researchers said.

Scientists have long warned that a warming planet may increase the burden of diseases. Malaria, for example, is expected to spread as the mosquitoes that carry it expand their range into warming regions. But climate change might also usher in entirely new diseases, by allowing pathogens to move into new host species.

“We know that species are moving, and when they do, they’re going to have these chances to share viruses,” said Colin Carlson, a biologist at Georgetown University and a co-author of the new study.

To understand what that sharing will look like, Dr. Carlson and his colleagues built a computer model of potential spillovers in a warming world. The researchers started by projecting how thousands of mammals might shift their ranges as the climate changes between now and 2070.

As temperatures increase, many species are expected to spread away from the blazing Equator to find more comfortable habitats. Others may move up the sides of hills and mountains to find cooler altitudes. When different species come into contact for the first time, the viruses may be able to infect new hosts.

To understand the odds of a successful new infection, the researchers began by building a database of viruses and their mammalian hosts. Some viruses have been found in more than one species of mammal, which means that they must have jumped the species barrier at some point in the past.

Using a computational technique called machine learning, the researchers developed a model that could predict whether two host species share a virus.

The more that two species overlap geographically, the researchers found, the more likely they were to share a virus. That’s because the hosts were more likely to encounter each other, giving their viruses more opportunities to move between them.

Dr. Carlson and his colleagues also showed that closely related species were more likely to share a virus than were distant relatives. That’s probably because closely related mammals are similar in their biochemistry. A virus adapted to exploit one species is more likely to thrive in a relative. It may also be able to evade an immune system similar to one to which it’s already adapted.

These findings enabled Dr. Carlson and his colleagues to make predictions about what would happen when mammal species come together for the first time in a hotter world.

Among the 3,139 species studied, the researchers anticipated more than 4,000 instances in which viruses would move from one species to another. In some cases, just one virus will make the jump. But the models also predicted that multiple viruses carried by one species would spread to the other.

The researchers were not able to say exactly which viruses would move between which species. What matters, they argued, is the sheer scale of what’s to come.

“When you’re trying to predict the weather, you don’t predict individual raindrops,” said Christopher Trisos, an ecologist at the University of Cape Town and a co-author of the new study. “You predict the clouds themselves.”

Rachel Baker, a disease ecologist at Princeton University who was not involved in the study, said that the research was an important step forward in understanding how climate change will affect the world’s dangerous viruses. Previous studies have focused on single viruses, as opposed to surveying the entire world.

“It’s a great advance,” she said. “We want to know as soon as possible if there’s some link between climate change and pathogen spillover.”

Bats in Southeast Asia will be especially prone to these transmissions, the researchers found. As of now, many bat species in that region are limited to small ranges and don’t come into contact with each other much. But as the planet warms, these bats will fly quickly to suitable climates and encounter new species.

5 Responses to “Climate Will Bring More Novel Diseases”

  1. neilrieck Says:

    Adding onto the bad news: up to 40% of farmers honey bees did not survive the winter in Ontario. The number is 60% for Quebec. Experts are not sure if it was the long-cold winter, pesticides like neonics, mites, or a combination of the three. IMHO, people can yammer all they want about science vs politics but that activity becomes pointless when the the food supply is reduced.

  2. Yes. It is true so we have to battle the climate crisis first without delay 🌍

  3. ubrew12 Says:

    For decades the deniers have claimed that climate action is premature because ‘the Science is Uncertain’. But a casual perusal of that argument reveals that ‘uncertainty’ cuts both ways. The climate change consequence to transmission of viruses as deadly as the Coronavirus wasn’t understood before. Now it is. Does anyone feel safer for having ‘retired that uncertainty’? I certainly don’t.

    Many uncertainties remain. Let us pray they all retire themselves in our favor…

  4. ubrew12 Says:

    And if that sounds a little like ‘may the odds be ever in your favor’, that’s because you’re living in the Hunger Games, thanks to previous climate denial.

  5. rhymeswithgoalie Says:

    While the warming aggravates the viral situation, large monocultures of humans and large monocultures of livestock were already ideal situations for viruses to thrive and evolve.

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