The Pulitzer Center Ocean Reporting Network supported this story CASAMANCE, SENEGAL — On Senegal’s southern coast, where the Casamance River meets the Atlantic, fishermen are pushing back against the sea with whatever they have at hand, including sticks. Rising seas caused by a rapidly warming climate have pushed waves into rice fields here and eaten into communities where fishermen keep their homes. West Africa, especially Senegal, is among the world’s most vulnerable nations to rising waters.