Combine sugar and water in a pot and cook over medium heat. Cook until sugar is completely melted/dissolved. Turn off heat and allow mix to cool with rosemary sprigs.
Once cooled remove rosemary sprigs and set syrup aside.
Add ice half way to glass. Pour pear juice, rosemary simple syrup, lemon juice, and sparkling water.
Garnish with fresh pear slices or sprigs of thyme.