Houses built before 1939 use about 50% more energy per square foot than those built after 2000, mainly due to the tiny cracks and gaps that expand over time and let in more outside air.

Because great numbers of people go there, the islanders have built elaborate resorts, developed harbors and airfields, improved the beaches and have expanded sea and air routes.

The cause appears to be in part greater turbulence in the urban atmosphere as hot air rises from the built-up surface.