“We provide evidence that the world will not only get hotter, but sicker, in the coming decades,” said Gregory Albury, a biologist at Georgetown University in Washington, who co-authored the published study. Nature.
Irreversible even with +2 degrees scenario
By cross-checking climate models, data on habitat destruction and how virus transition from one species to another, this work paints an even bleaker trajectory for the future of the planet by 2070. And irreversibility, even if warming is limited to +2°C, worries the authors.
Their research—more than five years of work—uncovered the mechanism by which the coup ecosystems and disease transmission invested for the first time. In total, 3139 species of mammals were counted – this class of animals is the carrier of a wide variety of viruses that can be transmitted to humans. More and more wild species are being pushed out of their natural habitatwhich is destroyed by temperature increaserainforest regression, urban and cropland development, and the wildlife trade.
Then they “emigrate” to new territories more favorable for their presence. Where they are most likely to stumble upon hitherto unknown wildlife, whether natives or refugees. With such a geographical redistribution of ecosystems, more than 300,000 “first encounters” of species can occur, i.e. double the potential. Mixed for the first time, these mammals will form new communities, fertile ground for new crosses of infections, especially viral ones.
Bats as carriers
The study paints a future “web” of viruses jumping from species to species and growing as the planet warms. It predicts at least 15,000 transmission of the virus between species.
With the central role played by the bats : these mammals are actually a reservoir of many viruses that they contain without becoming sick themselves, but which can infect humans through the host animal – “zoonoses” in the origin of several epidemics such as Sars, COVID-19 Where ebola. Winged, small, fast, they have great potential to spread around the planet and thus infect more “naive” species that are encountered for the first time.
10,000 viruses may already be spreading
It is a more than alarming picture that we know that at least 10,000 viruses capable of transmitting to humans are currently circulating “silently” among wild mammals, the study highlights. How many will wake up and cross the human barrier? Will new families of viruses emerge? The study does not say this, but predicts areas of the planet where the mixing of fauna will be concentrated: tropical Africa, Southeast Asia, in places where the human population will also be denser in 2070. Specifically the Sahel, the Ethiopian Highlands and the Rift Valley, India, East China, Indonesia and the Philippines. Certain populations in Central Europe will also be concerned.
But the threat is more global and changing of the climate so fast that it “creates countless dangerous zoonoses right on our doorstep,” warns Colin Carlson, also a co-author and researcher at Georgetown University. Who compares this process with the rocking of a “snow globe”. According to him, it is too late to change the trend, but it is necessary to “recognize that global warming will become the main vector of the emergence of diseases, and prepare our health systems for it.”