Why Can't All Countries in the World Work Together, Knowing That None of Us Will Live Permanently on This Planet?

Like a frog in a well who sees only a small circle of sky and thinks it's the whole world, countries view everything through their borders, as if these man-made lines are all that matters.

Me, in the snowy Yukon wilderness | Captured with tripod

Why can't all countries work together when we all know our time on Earth is limited? When we think about it, everything we own, achieve, and build will only last for a short time — just like us. Even if we live for 100 years, that's tiny compared to Earth's 4.5 billion years of existence. So why do…