Can't believe what is happening to this world? Apparently not a history major. Just a few wars worth mentioning.
10 Deadliest Wars In Human History
Throw in the top ten natural disasters. (Doesn't include the "great flood", if you believe in that one)
10 Worst Natural Disasters of All Time | Disasterium
Only listed the top ten in each category. Plenty more to chose from if you care to look them up.
So, overall, things aren't quite as bad as those with short memories would have us believe.