It’s an old refrain in the face of the great problems of the world and, of course, the standard answer is to do what you can. Every little helps. Something that takes a strong will and dedication to purpose. And getting organised to make political changes is not always that easy either, and the changes take decades because there is nothing more conservative or desiring of the status quo than economics.
There is a mind game you can play. If all the world vanished and all that was left was you, how much of the culture, history and thoughts of the human race would exist? You have a brain that is more complex than the patterns of the galaxies in the cosmos and one would assume you could have most of it squirreled away in your brain.
At least the highlights. And if you have those and live by them, the world would already be better than it is.