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.
Climate change derives from Stefhan-Boltzmann’s law together with the spectral dependence of the emissivity of various gasses. Stefhan-Boltzmann’s law has fundamental theoretical and experimental support.
This is the basis upon which climate models rest. This basis is unquestioned.