Global warming means we may now face the killer combination of mega drought and extreme rainfall that proved deadly for 17 million of the population in Aztec Mexico.
A particular pattern of weather sets the stage for a rodent bourn virus to spread with terrifying rapidity.
These deadly organisms mutate and adapt – the Aztec epidemic spread so quickly and killed so many people because it evolved to pass from human to human… And the 21st century world is potentially much more vulnerable to a global pandemic.