The effects of what we choose to do in our lifetime can usually only be seen later in life. Or even long after we're dead. So while we're maybe not changing the life of everyone on the planet, the instant we make a decision, it will definitely change something in the future..................... Butterfly Effect........
But if you're tlking LONG term. Why bother doing anything. In another few million years or so, the sun will explode
issed: and the whole earth will be wiped out. And even if we get off the planet, (and out of the solar system obviously!) eventually the universe will collapse, or something else would wipe out all life.
And what was the point in it all then???