My generation had Satanic Panic. Parents feared that satan worshipers were ritually abusing children. The stories fed upon themselves. Psychologists got in the business of "recovered memories", now-discredited. Parents saw evidence where there was none, until there were more than ten thousand police reports of ritual abuse. They weren't substantiated.
The Salem witch trials were not an anomaly. We create an enemy in times of peace. We gravitate to a cause.
You appear to be claiming that climate change is not an existential risk? The term boogeyman includes the judgement that the fears were unfounded. Climate change is a demonstrable real problem, and consequently not a boogeyman.
For something to be a boogeyman, it has to be an imagined danger that captures the fears of a lot of otherwise rational people.