Humans have lived well on earth, so why immigrate?

79% of the earth's surface is ocean, and only 2 1% is land. Most of these 265,438+0% are mountains, rivers, deserts, swamps and extremely hot and cold places. The area suitable for human habitation and survival is 15% of the whole earth area. There are already 7 billion people on the earth, and it is still growing.

Moreover, the earth's ecology is still deteriorating, and energy is also a big problem, so we have to bother to emigrate to other planets.