What if life had no meaning?

In surrounding velvety blackness, a small blue and green sphere turns slowly, white clouds whirling about it like the robe of a benign wizard.  The tiny, perfect orb is teeming with life.  It is the humans that are most powerful,  but they are not the most numerous nor the most powerful of earthen creatures, only the most intelligent.  Each human, one of six or seven million others, went about there lives, unable to accept, at some fundamental level, that they were not the center of the universe, that their superficial troubles did not matter more than everyone else’s.  They believed that their planet mattered as well, were so worried about this thing they called ‘global warming,’ which they themselves had caused, and if not stopped would eventually destroy the planet.  If the planet known as Earth were destroyed, it would affect very little else.  What happens when a single bacterium dies?  A single bacterium dies.  Nothing more, really, except there is an infinitesimally small amount less life in the world.  Yes, the humans would say, yes, nobody cares when a bacterium dies, but we are an entire planet.  We are important.  We matter.  But the truth is, little humans, your planet is no bigger—in fact it is a great deal smaller—than a single bacterium is in comparison to the rest of the world.  If the Earth imploded, there would be perhaps a bit of noise, perhaps a small poof, but nothing else.  The Earth’s one, pathetic moon would be affected, would fly out of orbit and become an asteroid or something, but little else would change.  So, really, how can the life of these puny little humans have any meaning, when their death—even their very extinction—affects so little, when their planet is infinitesimally small, when they themselves are less than tiny moving specks?  It seems improbable in the extreme, impossible, even ludicrous.