The Economics of Daylight Savings Time

Written by Cathy Sui (W’29), Edited by Jessica Hua (W’26)

Twice a year, approximately one-third of the world’s countries adjust their clocks forward or backward for an hour. These countries often lie in regions far from the equator and hope to gain extra sunlight in their days through shifting their clocks. Originally, these regions hoped to enhance energy savings by reducing the use of artificial lighting in the evening. As the world rapidly globalizes and advances in technology, are these goals still being achieved?

The concept of Daylight Saving Time (DST) was first proposed in 1895 by George Hudson, a New Zealand entomologist who wanted to give people more sunlight in the summer. By moving the clock forward an hour, people would enjoy an extra hour of daylight as the sun seems to rise and set an hour later. The period of the year where the clock is moved an hour forward is called Daylight Saving Time, and the rest of the year is called Standard time. People can use this extra hour of daylight to work or pursue hobbies. Particularly for Hudson, he wanted more sunlight to work on his insect collection.

The proposal was initially controversial, though it gained support from several political leaders including Winston Churchill, David Lloyd George, and King Edward VII. Germany first led its allied countries to adopt DST in 1916 to conserve fuels during WWI, and the initiative was quickly followed by the United Kingdom and other European countries. In 1918, DST was officially implemented in the United States under the Standard Time Act. Today, 48 U.S. states and Washington D.C. adopt DST, with the exceptions of Hawaii and parts of Arizona.

When DST was first practiced last century, its influence on energy conservation was apparent. However, whether the practice can achieve the same level of efficiency is a difficult question to answer in the modern world of rapidly advancing technology. Modern LED bulbs use significantly less energy than the incandescent bulbs that were common when DST was first implemented, meaning that one hour of extra artificial lighting has a tangential impact at best. Furthermore, the prevalence of electronics, charging sources, and air-conditioning all encourage longer periods of indoor activity. In many areas, an extra-hour of sunlight demands for more cooling in summer evenings and heating in winter mornings.This is why recent studies on DST often cite annual energy-use reduction of only between 0.3% to 1%. Many argue that such minimal impact is not worth the hassle of switching clocks twice a year.

Another argument against DST is the trouble of sleep deprivation. In addition to losing one hour of sleep during “spring forwards,” shifting clocks could disrupt the human body’s internal circadian rhythm, causing sleep fragmentation that’s similar to the impact of a mini jet lag. In the long term, sleep loss is linked to cardiovascular risks, accidents due to fatigue, and cognitive and mood impact. In fact, during the first-week after the clock changes, people are found to be less productive and rates of heart attacks and suicides tend to rise.

Moreover, in a highly globalized world, DST can also bring challenges in scheduling meetings across time zones. The problem is due to the fact that many countries start and end DST on different days. Say if you are trying to arrange a meeting for people located in New York, Paris, and Melbourne, their DST schedule varies because they are in different locations of the world, creating up to eight possible time differences between just three cities. Meanwhile, territories within countries can be inconsistent in practicing DST. For example, Canada observes DST but not Saskatchewan. Australia observes DST except for Queensland, the Northern Territory, and Western Australia. In the United States, Arizona is one of the two states that does not practice DST, but the Navajo Nation within the state does. These uncoordinated clock-shifts can add extra complication in scheduling on top of existing time zone differences.

Many once profound practices have faded in our rapidly changing world. Will DST be dropped like a written letter, typewriter, or handcraft skill? No one knows. When society evolves to the point that an invention’s benefits are no longer needed, it may be best to leave such practices to history.