Climate change is leading to a large number of animals fleeing their ecosystems. But by mixing in this way, species transmit more viruses, which contributes to the emergence of new diseases that could potentially infect humans, research predicts.
“We’re working on evidence that in the coming decades, the world will not only be warmer but also sicker,” warns Gregory Albery, a biologist at Georgetown University in Washington and another author of a study published in the journal Nature on Thursday.
The study, which cruised several climate models, information on the destruction of natural habitats and the spread of viruses between species, paints a grim scenario for the future of the planet over the next five decades.
According to the authors, an irreversible future, even if global warming is limited to two degrees, the authors say.
Studies lasting more than five years have revealed a link between ecosystem change and the spread of disease.
A total of 3,139 mammalian species were considered in the study, and there is a wide range of human-susceptible viruses in this animal class.
More and more wild animals are fleeing their habitats, which are deteriorating due to rising temperatures, declining tropical forests, urbanization and the advancement of farming areas, and trade in wild species.
Animals “migrate” to new areas that are more conducive to their presence, but are at risk of encountering species unfamiliar to them.
In this way, ecosystems are redistributed geographically and more than 300,000 “first encounters” can occur between species.
When these mammals first mix, they form new communities, fertile soil for new, predominantly viral infections.
bats as vectors
Research sheds light on the future “network” of viruses that will jump from species to species and multiply as the planet warms. The study predicts the spread of at least 15,000 viruses between species.
Bats play a key role in this scenario, as they contain a large number of viruses but do not develop the disease. However, they can infect humans through another animal, a process called zoonosis, through several epidemics, such as SARS, Covid-19, or Ebola.
Bats also have a high chance of spreading the virus and can infect many species they encounter for the first time.
The picture is more worrying when it is known that a virus capable of jumping at least 10,000 people is currently circulating “quietly” among wild mammals, the study highlights.
The study also shows where these processes are taking place: tropical Africa, Southeast Asia and the regions with the densest human populations in 2070.
The impact will also affect the Sahel region, the Ethiopian highlands and the Rift Valley, India, eastern China, Indonesia and the Philippines, as well as some populations in Central Europe.
But climate change is happening so fast that “it is creating countless dangerous zoonoses on our doorstep,” warns Colin Carlson, another author of the study and a researcher at the University of Georgetown.
The scientist compares the process to shaking a “snowball.” He says the trend is too late to reverse, but it must be “recognized that climate change will be the main vector of disease onset and finally prepare our health systems”.