I work hard. I worry about retirement, about having kids. I can't AFFORD to spend "extra" to go green. I will do what is cheapest. If, in the long run, a 30 mpg car helps my pocketbook over a 50 mpg car, I'll get it. I make no apologies.
You worry about having kids. That's normal. Are you worrying about the cost of having kids or the costs that they might incur?
Because "in the long run" it's going to be awfully expensive when your children, say, get cancer, have to pay their Sorry-we-fucked-over-Java reparations, have to relocate away from the newly classified flood zones, have to ship in potable water, have to pay extra for bread because the wheat zone decided to move a few parallels north.
Those are REALLY expensive things that your kids might have to pay for. And collectively, if any of this climate change scaremongering is true, they're going to pay for it one way or another. It might even be you paying for it, if you live long enough or get unlucky. It's like an education. It might be expensive, but ignorance is usually more expensive.
If you were just looking out for yourself, and you didn't expect to live very long, your argument would be valid. But if you plan of having kids... well... it's time you started looking at the long term costs and realize that your pocketbook depends on larger issues just as much as it depends on how much you put in and take out. As sappy as it is, we're all in this together.