Urgent wake-up call: climate change linked to COVID-19

Climate change may have directly contributed to the emergence of SARS-COV-2, the virus that causes COVID-19, according to a new study from the University of Cambridge. The alarming research has revealed that climate-driven forest growth in Southern China now supports dozens of additional bat species, along with 100 more types of coronaviruses.

“The fact that climate change can accelerate the transmission of wildlife pathogens to humans should be an urgent wake-up call to reduce global emissions,” said Professor Camilo Mora of UH Manoa, who initiated the project.

The findings represent the first evidence of a mechanism that links climate change to the pandemic. The experts report that large-scale changes in the vegetation across southern China have created the perfect environment for bats to thrive in. 

Rising levels of atmospheric CO2 and higher temperatures have transformed tropical shrubland into deciduous forest, which is the most suitable habitat for bats. 

In any given area, the number of coronaviruses present is closely linked to the number of bat species nearby. The experts discovered that an additional 40 bat species have moved into the southern Chinese Yunnan province in the past century, harboring around 100 more types of bat-borne coronaviruses. Genetic data suggests that SARS-CoV-2 originated in this global hotspot.

“Climate change over the last century has made the habitat in the southern Chinese Yunnan province suitable for more bat species,” said study first author Dr. Robert Beyer. “Understanding how the global distribution of bat species has shifted as a result of climate change may be an important step in reconstructing the origin of the COVID-19 outbreak.”

For their investigation, the researchers created a map of the world’s vegetation as it was a century ago. Next, they analyzed the global distribution of bat species in the early 1900s. By comparing this to current distributions, the experts could derive how the number of bat species  changed across the globe over the last century due to climate change.

“As 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 most likely allowed for new interactions between animals and viruses, causing more harmful viruses to be transmitted or evolve,” said Dr. Beyer.

Each bat species harbors an average of 2.7 coronaviruses, while the world’s bat population carries around 3,000 different coronaviruses. A climate-driven increase in bat species in any region also increases the chances that a coronavirus could be introduced to humans in that area. 

While most coronaviruses carried by bats cannot jump into humans, there are now three such deadly viruses that have, including Middle East Respiratory Syndrome (MERS) CoV, and Severe Acute Respiratory Syndrome (SARS) CoV-1 and CoV-2.

The researchers found that climate change has also increased the number of bat species living in Central Africa, and in parts of Central and South America.

The study is published in the journal Science of the Total Environment.

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By Chrissy Sexton, Earth.com Staff Writer