Isn't it basically the bible, except God is married to Mother Nature and neglects her over the humans? More and more humans come about, which keep trashing her house (the Earth) more and more, to the point where she can't keep up with the repairs. Finally, she has enough and loses her shit and just torches the whole house to the ground. God comes, takes her heart out of her chest to remember her by, and finds a new Mother Nature to build a new house to live in, repeating the cycle. The heart looks like the stone in his study earlier in the film that eventually gets broken, which indicates that Jennifer Lawrence isn't the first Mother Nature God's been with, and the result was the same as Jennifer Lawrence's character.