When else should we take action? There is really only now

But not here. (they take our rain!)

We should take action now, with urgency. My point is, manipulating people is not the way to motivate them to take action.

losing more atmosphere to convection? i don't think that's how that works

Put important things in flood-safe boxes, at least. Or just move them to a place that isn't at risk of flood.

Idk what level of flooding we're talking, but maybe you could put in some mitigation measures around your house? Stuff like making sure the ground is angled to send water away from the house and into the street, just digging out retention ponds, removing impermeable surfaces..
If we're talking BIG floods then yeah ultimately the house will have fish moving in, but it could still buy you time before the water starts claiming the house.

I vaguely remember some slips away over time, and is generally ~replaced by space bullshit that burns off in the atmosphere. We are on a rock swishing around in mostly-vacuum.

i looked it up properly and according to https://faculty.washington.edu/dcatling/Catling2009_SciAm.pdf we basically only lose hydrogen and helium, and we do so very very slowly (3kg/s for hydrogen, 50g/s for helium).

Well,pretty close for a guess based on nothing. I guess we can be confident we'll have an atmosphere to cook in.