Christian Science Monitor: Each Saturday Delia Cascamayta hops on a bus to the colorful produce market in Cuzco, Peru. There she sells the bananas, yucca, potatoes, and oranges that she grows on a 25-acre patch in the Sacred Valley, named by the ancient Incas for its fertile soil. But as one of several farmers dependent on river water that originates from melting glaciers here in Peru, her feelings about her future are far less bright than the intense hues of her fruit display. "What’s going to …