The world is far more resilient than the human species. Like The Magic has said life on earth is a constant state of creation and destruction. It is how nature corrects itself: one diaster to prevent another.
So if Mother Nature should cast out the final eviction notice, all we can really do is barricade ourselves into our homes an wait it out. What difference would the complete obliteration of the human race mean to the rest of the universe? You have a place over 28 billion lt-yrs with countless galaxies and probably countless intelligent creatures (so says the Drake Equation
http://www.pbs.org/lifebeyondearth/listening/drake.html): one planet gone can't even be compared as a drop in the bucket. The end for us... oh well, plenty more where we came from.