Veil of ignorance version: if you could designate some X% of earth’s land area for equal distribution among all humans at birth, but have to take a random lot yourself when born, which X% would you designate?
If you designate only a small guaranteed nice fraction, everyone gets a tiny patch but guaranteed nice. If you designate all of earth land area, you might get a large, nice patch for yourself… or a lousy patch of Sahara or Siberia.