If we’re capable of interstellar travel and the terraforming of other planets, why don’t we just fix the planet we’re already on? If we can terraform Mars, surely we can terraform Earth.
Anyone else excited for JWST, the successor to Hubble?
Its supposed to launch in March 2021, but unfortunately it's very likely going to get delayed once again, this time because of the coronavirus. When this video was made, the launch date was 2018.
The planet has finite resources, except for solar energy (and the occasional meteorite adding a few kilos of material). Limiting our resource use has limits, specifically, the limits of human population itself.
If we aren't willing to limit the human population, then our focus should be extraterrestrial colonization. There is no "fixing" the earth--you can't get around the fundamental resource scarcity. We're already running up against shortages of rare materials.
Interestingly, Star Trek's post-scarcity space utopia was based around (1) nearly infinite energy sources and (2) technology that converts energy into useful matter: food replicators, transporters, holodeck constructs, etc. If you think those two breakthroughs are feasible, then sure, you can stay on Earth and repair things. Otherwise, get out into the stars and find other resources to consume, both energy and materials.
(And if you think the energy problem is trivial, read Asimov's The Last Question. Or read the manga adaptation here or here. Given a long enough timeframe, entropy dictates humans choose between extinction or evacuation.)
Why not both?
Improving the earth could be achieved through colonizing nearby planet in our solar system, and it's not entirely unrealistic either when you consider the abundance of resources that could be harnessed through doing so.
Colonizing the solar system shouldn't be our priority though since we don't want to lose everything there is on earth such as liquid water and life.