Environment is not infinite, it has its limited resources, so it’s good for each of us to take care of it and avoid its destruction.
If we are negligent to our houses then dirt comes in, mess everywhere, dusty and nasty and unpleasant to live.
Is this what we want with our nature, or planet?
You will go to another planet? Really? To Mars?
There is no other planet like ours in the whole known universe, and if there is one, there is no way we can move all there.
First, because there is no technology for that.
Second, because we will be like parasites, draining the host and leaving for another.
So, let’s appreciate what we have and take care of it as much as we can.