"1. There's nothing I can do about it."
True. It would take everyone on Earth changing their way of life to tip the scales
"2. I'll be dead long before it has any tangible effect on my existence."
How old are you? We've got maybe ten years at most before the next great extinction event starts cascading.
Rainforests are no longer the carbon sinks they used to be, and with millions of acres cut down every year on top of the millions of acres lost to forest fires, we are decades past the point of no return. If we converted everything to "clean energy" tomorrow, it would take millennia to suck all the CO² we've already put into the atmosphere over the last hundred years.