Yep, closing in on 400 ppm.
The greenhouse analogy is messed up in a lot of different ways. The first of which, is that the planet’s atmosphere is not contained in a small glass box.
Greenhouses also tend not to have thunderstorms with thunderheads, hurricanes, or weather fronts of any kind. They further tend not to have a point of elevation within them above which water vapor does not rise.
As for the climate models there are a lot of things they don’t account for. The primary one is the behavior and varying presence of clouds. Since they don’t know whether the net effect of clouds is positive or negative, nor the pattern to the clouds appearance, they just decided to skip that issue in the models and give water vapor a positive feedback.
Sorry. I see you got there.