A new study published today in journal Science of the Total Environment provides the primary evidence of a mechanism by which global climate change could have played an immediate role within the emergence of SARS-CoV-2, the virus that caused the COVID-19 pandemic.
The study has revealed large-scale changes within the sort of vegetation in the southern Chinese Yunnan , and adjacent regions in Myanmar and Laos, over the last century.
Climatic changes including increases in temperature, sunlight, and atmospheric CO2 — which affect the development of plants and trees — have changed natural habitats from tropical shrubland to tropical savannah and deciduous woodland.
This created an appropriate environment for several bat species that predominantly sleep in forests.
The number of coronaviruses in a neighborhood is closely linked to the amount of various bat species present. The study found that a further 40 bat species have moved into the southern Chinese Yunnan within the past century, harbouring around 100 more kinds of bat-borne coronavirus. This ‘global hotspot’ is that the region where genetic data suggests SARS-CoV-2 may have arisen.
“Climate change over the last century has made the habitat within the southern Chinese Yunnan suitable for more bat species,” said Dr Robert Beyer, a researcher at the University of Cambridge’s Department of Zoology and first author of the study, who has recently taken EU research fellowship at the Potsdam Institute for Climate Impact Research, Germany.
He added: “Understanding how the worldwide distribution of bat species has shifted as a results of global climate change could also be a crucial step in reconstructing the origin of the COVID-19 outbreak.”
To get their results, the researchers created a map of the world’s vegetation because it was a century ago, using records of temperature, precipitation, and cloudiness . Then they used information on the vegetation requirements of the world’s bat species to figure out the worldwide distribution of every species within the early 1900s.
Comparing this to current distributions allowed them to examine how bat ‘species richness’, the amount of various species, has changed across the world over the last century because of global climate change .
“As global climate change altered habitats, species left some areas and moved into others — taking their viruses with them.
This not only altered the regions where viruses are present, but presumably allowed for totally new interactions between animals and viruses, causing more harmful viruses to be transmitted or evolve,” said Beyer.
The world’s bat population carries around 3,000 different kinds of coronavirus, with each bat species harboring a mean of two .7 coronaviruses — most without showing symptoms.
A rise within the number of bat species during a particular region, driven by global climate change , may increase the likelihood that a coronavirus harmful to humans is present, transmitted, or evolves there.
Most coronaviruses carried by bats cannot jump into humans. But several coronaviruses known to infect humans are very likely to possess originated in bats, including three which will cause human fatalities: Middle East Respiratory Syndrome (MERS) CoV, and Severe Acute Respiratory Syndrome (SARS) CoV-1 and CoV-2.
The region identified by the study as a hotspot for a climate-driven increase in bat species richness is additionally home to pangolins, which are suggested to possess acted as intermediate hosts to SARS-CoV-2.
The virus is probably going to possess jumped from bats to those animals, which were then sold at a wildlife market in Wuhan — where the initial human outbreak occurred.
The researchers echo calls from previous studies that urge policy-makers to acknowledge the role of global climate change in outbreaks of viral diseases, and to deal with global climate change as a part of COVID-19 economic recovery programmes.
“The COVID-19 pandemic has caused tremendous social and economic damage. Governments must seize the chance to scale back health risks from infectious diseases by taking decisive action to mitigate global climate change ,” said Professor Andrea Manica within the University of Cambridge’s Department of Zoology, who was involved within the study.
“The proven fact that global climate change can accelerate the transmission of wildlife pathogens to humans should be an urgent warning call to scale back global emissions,” added Professor Camilo Mora at the University of Hawai’i at Manoa, who initiated the project.
The researchers emphasised the necessity to limit the expansion of urban areas, farmland, and hunting grounds into natural habitat to scale back contact between humans and disease-carrying animals.
The study showed that over the last century, global climate change has also driven increases within the number of bat species in regions around Central African Republic , and scattered patches in Central and South America.