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A virologist says there are
in the permafrost that are more than 50,000 years old. These could be harmful to
. The
said unknown, "
viruses up to a million years old" could be terrifying because we have never seen them
. He added that deadly
diseases like smallpox could be released
. Factor X could be an even bigger problem. However, many scientists say the
of methane is a bigger
from melting permafrost. Methane is a greenhouse gas that is 80 times more
than CO2.
