Place tea bags in a large heat-proof container. Add boiling water, cover and set aside to steep for 5 minutes. Remove tea bags and discard. Add sugar and stir until it dissolves.
Pour tea mixture into a large saucepan. Add ginger. Heat over medium-high heat. Carefully add pears, cut side down and bring to a simmer. Reduce heat to medium-low. Simmer for 18-20 minutes or until pears are tender. Remove ginger. Set aside to cool.
Transfer pears to a serving bowl using a slotted spoon. Pour syrup over pears. Serve with vanilla ice cream and sprinkle with walnuts.