Yes, scientists have found that global warming can reactivate the many unknown and long-dormant pathogens such as viruses and bacteria, found hundreds and millions of years ago.
According to Jean-Michel Claverie, professor of genomics at Aix-Marseille University in France, viruses are like seeds buried and frozen into the soil for thousands of years and will germinate in a warm environment.
Claverie and his team were able to revive a 30,000 years old Siberian virus in their lab. Similarly, many dangerous viruses and bacteria might come to life along with deadly infectious diseases due to climate change.
