[Serious] Generally speaking, is philosophy a worthwhile subject of study?

[brewer]

Philosphers are, very often, involved in social sciences, yes.  Even the theologian I used as an example premises his notion of what it means to be sacred on hard data and observable relationships which come from contemporary scientific investigation, rather than any a priori x, revelation, or need to reverse engineer a justification for a particular ideology.  

Environmental action is informed by, and was created as a movement by, philosophy.  I suspect that it's going to be impactful IRL, at least as impactful as it has been for theologians like Crosby and their ideas about divinity, and at least in part because of explications like Crosby's.  We didn't just wake up one morning and say "let's save the planet and ourselves".  We were persuaded, and not at all uniformly, so there's work still to be done.

And if I took environmental action prior to any philosophical movement? Was the movement really based originally in philosophy or later defined as philosophy because that's what philosophers do?

Stop trying to make me believe your belief. Maybe you should start a church.