This description provides information about the total number of World Heritage Natural Landscapes as of 2019. As of this year, there are no World Heritage Natural Landscapes, as none have been designated by the United Nations Educational, Scientific and Cultural Organization (UNESCO).
From Wikipedia
World Heritage Sites are landmarks and areas with legal protection under an international treaty administered by UNESCO for having cultural, historical, or scientific significance. The sites are judged to contain "cultural and natural heritage around the world considered to be of outstanding value to humanity".