Australian National University has run seven scenarios on the likely worldwide outcomes of the SARS-CoV 2 viral pandemic.
Best case scenario (low severity model): Global GDP loss of $2.4 trillion with an estimated 15 million dead.
Worse case scenario (high severity model): Global GDP loss of $9 trillion with an estimated 68 million dead.
These models used the 1968-69 Hong Kong flu pandemic (which killed around 1 million people) a guide for their estimates.
None of this is definitive (as they authors themselves say). But it does help highlight the magnitude of what we couldâ€” and likely areâ€”facing.