Why would we need a "New Heaven" (re: Revelation 21:1 passage: "I saw a New Heaven and a New Earth")? Maybe because "Heaven" is that "should be" or "as it was meant to be" realm that exists as ever present possibility alongside earthly realities. We are, perhaps, called to re-imagine our whole way of doing things, which will require a new way to see "should be" that takes into account the sacredness of our status as "creatures" that are interdependent and share the earth and it's bounty.