Another non-committal response might be "we all contribute in our own little ways". Which I think is true, too. I believe everything impacts everything else in some way. You've heard of the butterfly effect - it flaps its wings and there's a storm instead of calm skies on the other side of the planet a day later. Even small actions can ripple outward and have major effects down the line. So I think we're all changing the world, every minute of every day, in a completely literal sense. Everything matters.