Conservation

While i just took a shower, i just remembered a conversation i had some time ago with peoples where it went along the lines like...

You know how energy is conserved?
You eat food, then you use the energy from the food you have just ate to do other things which inturn transforms the food energy you just had to something else, 'releasing' the energy outside you body, back to the earth, where the food you ate originally came from. Or you die, which your corpse lies as nutrients back into the soil where the plants absorb from then they do their shit then you eat them again.

For example, you see a fat person. Where does the fat of that person come from? Maybe the fat in the meals that the person eats? Then lets say the meal is pork or something, then the fat comes from the ... well fat of the porkpig. Which comes from the meals that it eats, and ultimately, the whole pig comes from its mother, which gets its energy to give birth to another piglet from the food that she eats.

All is cool, energy is a cycle and never ending, just continuously transforming from one form to another. Energy is conserved.

Let's say there is actually a value to the energy that exist on Earth, for the sake of argument, a value of 10000. This value of 10000 are the total energy on Earth, always at 10000, whether there is less nature or more population, it is a constant ratio of energy which is there for Earth to function. That means if a large portion of humans migrate to another planet or something, the humans take a portion of that energy with them, away from Earth. So then the constant of 10000 will decrease and Earth could not function as well as how it was supposed to.

Of course this is ignoring factors such as solar waves or gravity within the universe.

In the end, the Earth is just a part of the huge universe. If humans did indeed move to another planet, we are simply moving the energy from Earth to another planet, energy, as a whole, is still conserved within the universe. If Earth dies, that part of the energy will just be released back into the 'nature'.

If you didn't understand any of that, this macrocosm could be translated into a simple microcosm.

You are locked in a house, and you are unable to leave. Then this guy comes and ninja your fridge. You die.