The world has entered a "pandemic era".
That's according to the top U.S. infectious disease expert Anthony Fauci.
He is one of many scientists who say, that infectious diseases can now spread more easily, and they say environmental issues play a big role.
Researchers at Harvard University say, climate change and deforestation are destroying animals' natural habitats.
That forces animals to migrate into human communities,and potentially come into contact with other animals and people,where they could transmit viruses.
Most infectious diseases in the past decades, including SARS, MERS and COVID-19, can be traced back to these wild animals.
"Climate change affects the temperature and the amount of rainfall ….forcing animals and plants to change their habitats. What was once a forest could become desert,….and vice versa.”
Climate change can lead to the spread of diseases in other ways too.
It intensifies natural disasters like hurricanes and wildfires.
And they damage water supply and sanitation, increasing the risk of infectious diseases.
Scientists are also concerned about air pollution.
Studies show, people who are exposed to pollutants, are more prone to respiratory infections.
This was seen in a recent study, which showed that people who live in places with poor air quality are more likely to die from COVID-19.
Like this, human activities can increase the risk of infectious diseases.
But we can ALSO reduce that risk,by reducing pollution and greenhouse gases.
Lee Kyung-eun, Arirang News.