You can’t. All you can do is realize every trip you take and every bite of beef is yet another drop in the bucket. Every vote for a denialist is probably worth 100s of burgers too, sad to say.

You must choose if your hedonism outweighs the good of our biosphere now and in future. The billions of unborn humans. The trillions of innocent life forms that might go extinct. That blue bird or cardinal in the yard with no AC. The coral reefs decimated. The poor humans suffering tremendously. We have a choice to slightly reduce these things.

Most people choose hedonism.

There are some actions people can take that create massively outsized consequences. The CEOs of oil companies take many of these.