If you're strongly moved, you could commit your life to doing something about it. But it's also important to keep in mind that none of this likely matters long term, on the scale of millenia. Future historians will likely consider these times as far more tragic than the fall of Rome. But that's how it goes.
In my case, not exactly nihilism, but est/Landmark. Basically, there is no innate meaning or purpose, only whatever you say that there is. As a biologist, of course, I'd add that there's selection for reproductive fitness. But that's readily ignorable, if you're paying attention.
Maybe from a selfish and individualistic point of view (which is one of the reason things are going in the wrong direction), but if you have empathy and care about others people and life forms it is a very different matter.
I feel strange saying this, but really, it's not going to be that bad. Sure, human civilization may collapse. Billions will die. And we're pretty much locked into an historic extinction event.
But the human race won't get wiped out. And the global ecosystem will recover. It's not like Earth will flip into Venus mode. In a million years or two, this will all be just a blip.