It has been a miserable year for the global economy. But things can always get worse.

History says the Federal Reserve’s high-speed interest-rate hikes may well tip the U.S. into recession in 2023. Few will be surprised if spiraling natural-gas prices do the same for Europe. The double whammy of "COVID zero" and a property slump threatens to bring China’s economy to a near standstill.

And in an extreme downside scenario, all those things happen at once. That could wipe out some $5 trillion in global output, compared with more upbeat forecasts at the start of this year, according to Bloomberg Economics.