Every day, we humans dump billions of pounds of waste into the oceans, and not all of us know of this problem. We ruin life underwater because of this, and this will come back to stab us one day, most likely when the aliens have taken over our beloved planet. But do we really care for the Earth in the same way it "cares" for us? Would we really stay on this slowly-warming planet if we found out that there's another planet that could support human life?