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Writer's pictureLawrence Loh

On daylight saving disquiet in 2024: is a single world clock an idea whose time has come?

Updated: May 13


clocks on a wall show the time in different regions

Quick: tell me how you feel about daylight saving.


If you’re like most North Americans a week later, you’ve adapted, and so has everyone else; life has moved forward. 


The expressed frustrations around changing our clocks has faded into the background.


(Until the first weekend of November, at least.)


Much like vaccines, however, daylight saving appears increasingly a victim of its own success, after almost a century since its adoption.


Perhaps the Bush Administration’s 2005 decision to push out the start and end dates soured the practice for some. 


But as different jurisdictions that currently practice daylight saving increasingly explore sticking with one time year-round (and Yukon having made the switch), it's worth noting that most of the opposition to the time change exhibits the same biases that ail policymaking today.


For one: there’s a tendency to skip the full picture.


Most of the disquiet around daylight saving, not surprisingly, tends to emerge—briefly—twice a year: at spring forward, and to a lesser extent, at fall back. 


This has consequently shaped the research on the topic, where papers published on health impacts almost always focus on the ‘acute’ impacts; defined typically as within the first week, or at most weeks, after the time change—including all the papers cited in this website from one of my alma maters.


Still other papers appear to be based on expert opinion and hypothesis rather than hard data, including this paper in the Canadian Journal of Public Health which claims ‘social jetlag’ continues 'over 8 months'—which is at odds with conventional understanding that jetlag, for most people, resolves within one day for a one hour offset.


A narrow focus on the change itself also does not consider the broader health benefits that come from the switch over the entirety of the year: longer evenings that facilitate social connection and outdoor recreation; cooler mornings for fitness where 4am sunrises do not result in hotter, stickier 7am runs, and, of course, when returning to standard time, protecting children from a pitch-black walk to school during the darkest time of the year.


Evidence-based decision making would suggest that the practice of daylight saving should be assessed systematically and consider the full year in sum, accounting for all effects, positive and negative, rather than a narrowly circumscribed window around the change itself.


That brings us to the second issue, which is that daylight saving is a compromise—which is tricky in this day and age.


Opponents of the change who wish to choose a year-round time often fall into two camps: constant standard time, or some constant increment of daylight-saving year-round (usually the hour shift, but the suggestion to “go up half an hour and leave it there” is also common.)


Daylight-saving, though, is actually an effective, science-based compromise based on our observations of seasonal changes in sunlight arising from Earth’s orbit and tilt. It allows us to optimize sunlight during the longer days, where possible, while ensuring safety amid shorter days that aren’t amenable to the advanced hour.


Leaving clocks on either standard time or daylight-saving time year-round disadvantages different times of the year, and this story has been seen elsewhere.

Permanent daylight saving has been tried and abandoned in the United States in the 70s, returning to the present practice; the late sunrises in winter were cited as a particular reason for its abandonment—and no surprise, given that the sun would rise at 9.49am on December 21 if Edmonton, Alberta were on permanent daylight time, and presently rises at 11.10am in Whitehorse on the same day.


Permanent daylight saving was also tried for three years in Russia from 2011-2014 before being abandoned—for much the same reason—in favour of permanent standard time. 


However, Russia’s decision to not reinstitute daylight saving put it on par with countries like Japan and China; at the summer solstice on June 21, sunrise in Moscow is 3.44am; Tokyo 4.23am, and Beijing 4.48am, all in essence demonstrating that, without the hour offset, the “additional sunlight” of summer in these places comes at a time where folks are usually sleeping or otherwise indisposed.


Which brings us to the third phenomena observed in the public discourse around daylight saving: misattribution and misunderstanding. 


Many people express a dislike for standard time arguing that it causes darker, shorter days, and lower mood, without realizing that days in winter are simply shorter, regardless of whether one is on standard or daylight-saving time. In fact, a policy to move to permanent daylight saving might well exacerbate this by displacing sunrise later without expected (i.e. not summer-like) gains on sunset.


Similarly, proponents of daylight saving sometimes erroneously attribute the advanced hour as the cause of longer summer days, without realizing that the amount of summer sunlight remains the same—we’re just optimizing its use.


Taken together, though, we see the parallels of daylight-saving time with the challenges facing vaccine promotion and other effective interventions today. A century-long, effective practice being chipped away by a focus on the short-term costs, perceived inconvenience, and circumscribed data rather than the longer-term gains and a fulsome picture; misattribution of other phenomena onto the established practice, and a world that increasingly finds compromise and science-based decision making difficult.


In my mind, though, the most convincing litmus test is that, at the height of summer, the time change no longer registers: people are too busy enjoying their later evenings at the baseball diamond, on rooftop patios and trails, at festivals and concerts, enjoying time and spectacular sunsets with their family and friends.


But if people are truly tired of this effective practice of optimizing sunlight by changing our clocks twice a year, perhaps one solution to explore—which might truly be effective for the 21st century—would be to move the world to a single universal time and then, shift our daily routines accordingly.


This isn't a new idea, and would also have the ancillary benefit of eliminating time zones altogether; a world where you wouldn’t need to figure out what time it is elsewhere and figure out if they’re on daylight saving time or not. 


In a world on a single time, the question when we land in Los Angeles isn't "What time is it?", but rather, "What time do Angelenos usually go to work / eat dinner / go to sleep?” 


The clock remains the same and unchanging wherever you travel, whenever you takeoff or land, no matter where your meeting attendees are hailing from. 


Not surprisingly, in a world with a single, constant time, we shift our schedules to match time, rather than the other way around—which means we can also choose to shift with the seasons, if we wish.


For example, if we all were to coalesce around Universal Time Coordinated (formerly Greenwich Mean Time in London), one company or individual in Toronto might well choose to work from 14:00 to 22:00 through March 1, but 13:00 to 21:00 through November 1, while others might well decide to just stick to 14:00 to 22:00 (aka “the old Eastern 9-5”) all year long.


Schools could similarly shift their times to meet societal expectations and account for safety in the winter; all the while, the time in Toronto remains exactly the same as in Lagos or Tokyo, with lives in different cities simply unfolding around different parts of the clock.


The world would never have to change the time again, but the power to change schedules with the seasons remain, no matter where we sit; those who enjoy optimizing daylight could do so it if mattered to them—and those who'd rather not, could decide not to. 


Now, wouldn’t that be something?


Of course, finding consensus and driving such a change would be a Herculean task. But in our increasingly individualized world, perhaps it really is time …


This post originally appeared on Lawrence's LinkedIn profile.



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