How's it gonna end...

Well last time I checked, the sun's intake of specific gases has its size steadily increasing. Apparently in less than 2 billion years the first three planets will be consumed by the Sun, if the Sun doesn't die out by then. Humans will most certainly cease to exist since most organism have mechanism to eliminate foreign bodies and Earth will eventual do just that, of course depending on if it becomes consumed or not. By the way, I'm not actually stating the above as what will happen but rather what I imagine would happen.

If by world ending you mean the planet earth being destroyed, never. If by humanity being destroyed, you mean humankind as a race, never. If you mean the society of today that is ruining the earth, that is different. The one who made the planet et al, intended it to be here, inhabited by human society that will look after the earth and its animal and plant life, forever. The detour of the last few thousand years is just that, a detour. It doesn't change the original intentions, nor will it stop the final fulfillment of that purpose. No one needs to "play god". That part is already taken.