noun: harbinger; plural noun: harbingers
1.a person or thing that announces or signals the approach of another.
"witch hazels are the harbingers of spring"
synonyms: herald, sign, indication, signal, portent, omen, augury, forewarning, presage;
Baby seals are suffering from radiation.
70% of the seals in California have died this way now. It is a harbinger of what mankind has to look forward to.
No, this isn't alarmist. If anything the world is yawning when it should be on full alert.
Mankind had better wake up quickly as human mortality rates are climbing as well.
"How long shall the land mourn, and the herbs of the whole field wither? For the wickedness of them that dwell therein, the beasts are consumed, and the birds."
Note that it is 'wickedness' not just some little inconvenience or annoyance. It reflects on the spiritual state of humanity.