On a recent late night at the office, I got a warning from the cleaning woman: “You know the lights all shut off at 10 o’clock, right?” Fortunately, I had never stayed at National Geographic late enough to learn that fact. But I had noticed before that at 8:00 p.m., my computer sends a message saying it is going into sleep mode unless I click a button to keep it on.

Those automatic shut-offs are one of many small measures that have added up to big energy savings for the National Geographic Society. In fact, the Society’s facilities department announced earlier this year that NG achieved a record for energy conservation last year, hitting its lowest-ever level of energy use at