It was not hard to find Daylight Savings Time detractors this morning, in person or on the Web. For my part, I was surprised to find my morning bike ride plunged into darkness, and even more surprised that I was getting up almost two hours before dawn (which sounded a lot worse than it was).
I was not alone. A new blog post on Freakonomics argues that the lack of Monday morning sleep has a measurable effect on productivity, as tired workers are more likely to slack off than rested ones. The blog pointed to an average of 40 minutes of sleep lost as our circadian rhythms adjust to the time change, which makes groggy workers more likely to surf the Web and waste time. Pointing to the same study (originally published in the Journal of Applied Psychology), Patrik Jonsson wrote in Christian Science Monitor that there are also negative health effects to worry about, such as impaired immune responses and sleep deprivation. Huffington has even pointed to a possible increase in missed appointments, heart attacks and traffic accidents. Reportedly, the Applied Psychology researchers have called on Congress to rethink the anachronistic practice, as the costs outweigh any potential benefits.
For years people have put up with this imbalance mainly because DST was supposed to save on household energy consumption. But as Freakonomics coauthor Stephen Dubner pointed out in 2008, new evidence puts the old argument on shaky grounds. While people tend to turn off indoor lights during the now-sunlit evening hours, the benefits are offset by increases in heating and cooling during the morning twilight. The net effect, according to an NBER working paper was a slight overall increase in energy use nationwide.
So why do we still observe it? The practice isn’t all bad, says Nick Sawe of Stanford magazine. During the 1970s energy crisis–when DST was finally put into permanent practice–Americans saved “the equivalent of 10,000 barrels of oil a day” over a two-month period. The Department of Transportation also saw a decrease in auto accidents and crime. And some recent studies suggest that the old rationale that DST lowers energy use is right on–but only if DST is extended year-round. During the early 2000s energy crisis, California tried this approach with surprising success, a result the whole country saw when it increased DST by a month in 2007.
There is also a positive impact on renewables, says Sawe. Because DST reduces peak demand for energy–especially in the evening–it puts less stress on renewable sources like solar and wind that may be less consistent due to weather or other factors. And, as National Geographic‘s Brian Handwerk reveals, while DST energy savings is marginal to nonexistent nationwide, it’s much more measurable in areas outside the Deep South, like the Midwest and California coast. This is mainly because people in cooler regions are less likely to use air conditioning.
As controversial as DST is now, it’s hard to imagine how we’d ever get to observe it year-round. Ironically, this means we may never see the system’s greatest benefits. In any case, there is something to be said for an extra hour of sunlight in the evening–summer seems that much closer. Mornings will be tough for a while, but it won’t be dark forever.
Sources: Freakonomics Blog, Christian Science Monitor, Huffington Post, NBER, Stanford, National Geographic.
Image by Therese F (Photographerpandora) licensed under Creative Commons.
