What do you think is the most nightmarish scenario facing humanity? Zombies? :)
Source: MPH Online
The only one to really "fear" is the Super Volcano. We have the rest under control. Until the super volcano erupts, then all the others in play.
BTW, they left out a Super Tsunami.
You forgot the gamma ray burster pointed at Earth, WR104. Not to mention asteroid and comet collisions, magnetic pole reversal, universe phase shifting, 1859 style CME event et al…