The beaches are shrinking in Hawaii. It is not clearly linked to global warming though some website reports leap to make a connection.
Global warming or no, the current beach erosion is closely linked to other human activity. Upscale homes are built next to the beach. Research shows their expensive sea walls change the wave action and actually speed up beach erosion. So the wealthier beachfront developments will be losing their sand faster than other areas. Won't that affect real estate values? Perhaps there could be a greetech solution: virtual beaches so the homes could be built further from the real ocean to begin with? Solar-powered sand dredges to re-build the beach as fast as it waves away?