KALOKOL, Kenya — The lake that Philip Tioko relies on for survival is a fine turquoise strip that seems to recede farther into the distance each day. His fishing village once hugged the shore, but now it is 800 feet away, and everything — food, water and employment — is drying up.

Tioko, 46, remembers when fish were abundant in Lake Turkana, the world’s largest desert lake, and there was enough rain for his livestock. “I used to have so many animals. The lake used to be full — life was good,” he said.