Every now and then, I note down an interesting link, but don’t quite find a full article of my own to work it into. So here I’m going to list a few things that I’ve found around the web showing how Summer Time / Daylight Saving Time might not only fail to have the benefits some people claim for it, but actually have opposite and profoundly negative effects on people’s lives.
Safety is often mentioned by Daylight Saving Time advocates, but the fact that twice a year everyone has to break their daily rhythm actually causes extra accidents: Daylight-saving Time Leads To Less Sleep, More Injuries On The Job, Study Finds
Our bodies have a natural daily rhythm which closely tracks natural daylight, and is important to our mood and sleep patterns. It turns out, our bodies have trouble catching up when we move the clocks forward: Daylight Saving Time Disrupts Humans’ Natural Circadian Rhythm
Seasonal Affective Disorder (or SAD) is a particularly extreme kind of “winter blues”, which causes people real problems. But it turns out that while DST enthusiasts demand more and more light to be “moved” to the evenings, it’s the morning light that keeps SAD at bay: Springing ahead to a long March
It’s not really rocket science to realise that lack of sleep can lead to all sorts of medical problems, but here’s a run-down of some of the problems that “missing hour” causes: The onset of daylight saving time can be hazardous to your health
Meanwhile, reduced energy usage is a common claim for changing the clocks, often cited as the historical reason for its adoption, and why it’s so popular with environmental campaigners. But the research actually backing this up is largely based on simplified models, or is just plain out of date.
Sydney extended DST for two months for the Olympic Games in 2000, and researchers took the chance to measure the actual effect on a modern nation’s electricity usage. They concluded:
In this paper we question the findings of prior DST studies, which often rely on simulation models and extrapolation rather than empirical evidence. […] Using detailed panel data on half-hourly electricity consumption, prices, and weather conditions, we show that the extension failed to reduce electricity demand.
A similar study took place in Indiana in 2007, when they had an experimental extension, with even more negative conclusions:
Our main finding is that—contrary to the policy’s intent—DST increases residential electricity demand. […] These findings are consistent with simulation results that point to a tradeoff between reducing demand for lighting and increasing demand for heating and cooling. We estimate a cost of increased electricity bills to Indiana households of $9 million per year [and] social costs of increased pollution emissions [of] $1.7 to $5.5 million per year. Finally, we argue that the effect is likely to be even stronger in other regions of the United States.
Now, I admit that these articles are cherry-picked, and not a systematic review of the literature – although I’d welcome anyone who has the knowledge to make or find such a review. But they do show the importance of weighing all the options, and that just maybe we’d be better off putting our clocks more in sync with our sun-dials, and leaving them there all year around.
(Thanks to supporter Robert Nock for the links on energy usage.)