God created this whole wonderful world. He made it beautiful, happy and green. There were large green fields with grass and colourful flowers. Then God made birds and animals to live in the meadows and the fields, the woods and the forests. After that God created Man to take care of his beautiful creations. He made Man as the most intelligent and best of all his creations.
We must keep earth as green and as beautiful as I God created it. Do not commit any sin when you go to Earth. Or as a punishment the earth will lose its beauty and will turn into a vast desert."
Man started stealing, lying and committing other sins. So Earth turned into a vast desert. But when Man realized his mistake, then God forgave him. That is why there is still some greenery left on the Earth yet.