Over the next 50 years, climate change could lead to more than 15,000 new cases of mammals transmitting viruses to other mammals, according to a study published in temper nature1. She is one of the first to predict how global warming will alter wildlife habitats, increase encounters between species capable of swapping pathogens, and determine how often viruses are expected to move between species.
Many researchers say that the COVID-19 pandemic I may have started When a previously unknown coronavirus is transmitted from a wild animal to a human: a process called zoonotic transmission. The study warns that the expected rise in viruses jumping between species could lead to more outbreaks, posing a serious threat to both human and animal health—providing additional reason for governments and health organizations to invest in pathogen surveillance and improve healthcare infrastructure.
The study is “a critical first step in understanding the future risks of climate change and land use in the next pandemic,” says Kate Jones, who designs interactions between ecosystems and human health at University College London.
The research predicts that much of the transmission of the new virus will occur when species first meet as they move to cooler places due to higher temperatures. This is expected to occur most often in species-rich ecosystems at high altitudes, particularly regions of Africa and Asia, and in densely populated regions, including the Sahel region of Africa, India and Indonesia. Assuming that the global temperature rise is no more than two degrees Celsius above pre-industrial temperatures in this century – A future predicted by some climate analyzes The study says the number of first-time encounters between species will double by 2070, creating virus transmission hotspots.
“This work provides us with more indisputable evidence that the coming decades will not only be hotter, but much sicker,” says Gregory Albury, a disease ecologist at Georgetown University in Washington, D.C. and one of the study’s authors.
To make their predictions, Alberi and his colleagues developed and tested models, running simulations over five years. They combined models of virus transmission and species distribution under different climate change scenarios, focusing on mammals because of their relevance to human health.
The team built a species distribution model to predict where the mammals would move to find more habitable habitats as the planet warmed. The virus transmission model predicts the likelihood of virus transmission between species for the first time, by considering where species may meet as their habitats change and how evolutionarily related they are (viruses are more likely to pass between related species).
The modeling appears to be “technically flawless,” says Ignacio Morales Castilla, a global change ecologist at the University of Alcala in Spain, although he notes that forecasting exercises like this sometimes need to include unrealistic assumptions. But he adds that the breadth and scope of the research and its ability to identify which parts of the world may be most at risk “stand out clearly”.
One of the assumptions the researchers had to make was how widespread and expanding the species would be with climate change. But factors such as whether mammals are able to adapt to local conditions or cross physical barriers in the landscape are difficult to predict.
The study found that bats are expected to be involved in transmission of the virus regardless of these factors. Bats are thought to be part of the origins of COVID-19, which are known reservoirs of viruses and make up about 20% of mammals. The team says — in part because bats can fly — they are less likely to encounter barriers to changing their habitat.
The repercussions for humans?
Although Jones welcomes the study, she urges caution when discussing its effects on human health. “Predicting the risks of viral jumps from mammals to humans is even more challenging, as these spillovers occur in a complex human social and economic environment,” she says.
She adds that many factors can reduce risks to human health, including increased investment in healthcare or the inability of the virus to infect humans for some reason.
But the researchers urge there’s no time to waste. The Earth has already warmed more than 1°C above pre-industrial temperatures, and this is driving species migration and disease exchanges. “It’s happening and it can’t be prevented, even in the best-case scenario for climate change,” Albury says.
Alberry and one of its co-authors, Colin Carlson, a global change biologist also at Georgetown University, say that while some increase in disease transmission is inevitable, that’s no excuse for inaction. The researchers called on governments and the international community to improve surveillance and control of wildlife and zoonoses, particularly in future hot spots such as Southeast Asia. They say improving health infrastructure is also essential.
As people begin to prepare for and adapt to global warming, most efforts focus on activities such as halting deforestation or strengthening sea walls. But Carlson says pandemic preparedness and disease surveillance is also climate change adaptation.