Time is a strange thing. I'm not talking about the concept of time the way Einstein would think about it, but the time on the clocks. What the clocks around the world tell us is only something that we have all agreed upon. There is no natural 1:37 pm, it's a human construct. And, as such, we can magically make it be 12:37 pm if we want to. But we have to agree on it. And this agreed-upon change happens twice a year in parts of America. In much of America today, people are once again trying to remember how to set their wristwatches and stove clocks ahead one hour. Why? Because last night we started daylight saving time for 2007. But how did this time change start? Do we all benefit equally from the change? And what does this have to do with green cars? And why did we "spring forward" three weeks earlier this year and will "fall back" a week later in the year?

All will be answered after the break.

If there is one easy way to think about why we do the daylight saving ritual every year, it's that the move saves energy. Just look at how the California Energy Commission explains daylight saving time: "One of the biggest reasons we change our clocks to Daylight Saving Time (DST) is that it saves energy. Energy use and the demand for electricity for lighting our homes is directly connected to when we go to bed and when we get up. Bedtime for most of us is late evening through the year. When we go to bed, we turn off the lights and TV."

How can one argue with that? Well, Michael Downing, author of Spring Forward: The Annual Madness of Daylight Saving Time can. As he told NPR that the idea that more daylight equals energy savings is a crock.

"I'm certainly not a fan of the idea that it save energy," he said. "It turns out that every time Congress has studied it, it's been told that we haven't saved anything. In fact, the best study we have is from the Nixon era when he went on a desperate attempt of year-round daylight saving as a result of the OPEC oil embargo and he came up with nothing by way of saving except the potential again. Here's the problem with daylight saving as an energy saver: we tend to want our computers and our televisions and our radios when we want them. More important, daylight saving really pushed Americans out of the house at the end of the day. And when Americans go out of the house, they may go to the ballpark, they may go to the mall, but they don't walk there. They get into their cars. Daylight saving increased gasoline consumption, something the petroleum industry has known since 1930. ... This has been [a] tremendously effective spending policy. Retail stores love daylight saving. Because when we have an hour of sunlight after work, Americans tend to go shopping. The first and most persistent lobby for daylight saving in this country was the Chamber of Commerce, because they understood that if their department stores were lit up, people would be tempted by them. In 1986, Congress gave us an extra month of daylight saving time. That's when we went from six to seven months, which is the period we've been living with recently. In that Congressional hearing, [the] golf industry alone, these are industry estimates, told Congress one additional month of daylight saving was worth 200 million dollars in sales of golf clubs and greens fees. The BBQ industry said it was worth 100 million dollars in additional sales of grills and charcoal briquettes. ... For 25 years, the candy industry has wanted to get Halloween covered by daylight saving, figuring that if children have an extra hour of daylight, they'll collect more candy. In fact, they went so far during the 1985 hearings on daylight saving as to put candy pumpkins on the seat of every Senator hoping to get a little favor. They didn't get it then, but they got it this time." (Note this is my own transcription, not NPR's. I think I got everything right, but, you know...)

For an extended timeline of the history of daylight saving time, click here. One interesting corporate announcement that came across my virtual desk this week is from Lowe's, which combines the energy saving idea with the shopping message in 12 easy steps. Lowe's gives prices and product numbers and estimated energy savings for these projects.

The California Energy Commission does say that "studies done in the 1970s by the U.S. Department of Transportation show that we trim the entire country's electricity usage by about one percent EACH DAY with Daylight Saving Time," but that doesn't take total energy use (including transportation fuel) into account. Another study quoted on the page does: "Based on consumption figures for 1974 and 1975, The Department of Transportation says observing Daylight Saving Time in March and April saved the equivalent in energy of 10,000 barrels of oil each day." But, as National Geographic reported in 2005 when the current extension of daylight saving time was being debated in Congress, in 2001, then-acting deputy assistant secretary for transportation policy Linda Lawson said these old studies might not be all that applicable in the new century.

"I want to note that these studies are over 25 years old and were limited in scope," she said. "Congress captured many of the benefits identified in our studies in the legislative changes to daylight saving time enacted in 1986. There have been dramatic changes in lifestyle and commerce since we completed our studies that raise serious questions about extrapolating conclusions from our studies into today's world."

David Prerau authored some of those old studies and recently wrote a pro-daylight saving time book, "Seize the Daylight: The Curious and Contentious Story of Daylight Saving Time." He stands by the claim of a one percent energy reduction when daylight saving time is in effect. Downing says that has never been established, and the idea that America will save 100,000 barrels-of-oil a day with more waking daylight is "impossible, not just implausible."

So, where are we at now? There are now eight months of daylight saving time and only four or "standard" time a year. According to Downing, Congress has set aside $150 million to study the issue. This is not the end of the discussion, that's for sure.

[Source: NPR, Scripps News Service, National Geographic]