Gradients of heat and salt affect the propagation of sound energy in the ocean. Anticipated changes in oceanic conditions will alter thermohaline conditions globally, thus altering sound propagation. In this context, we examine changes in shallow- water propagation. Because these waters are close to the surface, they will be the earliest to change as the atmospheric state and radiative conditions change. We compare current and possible future propagation patterns near fronts and across fronts on continental shelves. Changes in sound pathways between the deep ocean and coastal regions are also examined, including an example from the Arctic Ocean.