Subtitles section Play video
-
Every year some countries move their clocks forward in the spring only to move them back
-
in the autumn. To the vast majority of the world who doesn’t
-
participate in this odd clock fiddling – it seems a baffling thing to do. So what’s
-
the reason behind it? The original idea, proposed by George Hudson,
-
was to give people more sunlight in the summer. Of course, it’s important to note that changing
-
a clock doesn’t actually make more sunlight – that’s not how physics works.
-
But, by moving the clocks forward an hour, compared to all other human activity, the
-
sun will seem to both rise and set later. The time when the clocks are moved forward
-
is called Daylight Saving Time and the rest of the year is called Standard Time.
-
This switch effectively gives people more time to enjoy the sunshine and nice summer
-
weather after work. Hudson, in particular, wanted more sunlight so he could spend more
-
time adding to his insect collection. When winter is coming the clocks move back,
-
presumably because people won’t want to go outside anymore.
-
But, winter doesn’t have this affect on everyone.
-
If you live in a tropical place like Hawaii, you don’t really have to worry about seasons
-
because they pretty much don’t happen. Every day, all year is sunny and beautiful
-
so christmas is just as good of a day to hit the beach as any other. As so, Hawaii is one
-
of two states in the Union that ignore daylight saving time.
-
But, the further you travel from the equator in either direction the more the seasons assert
-
themselves and you get colder and darker winters, making summer time much more valuable to the
-
locals. So it’s no surprise that the further a country is from the equator the more likely
-
it uses daylight saving time. Hudson proposed his idea in Wellington in
-
1895 – but it wasn’t well received and it took until 1916 for Germany to be the first
-
country to put it into practice. Though, the uber-industrious Germans were
-
less concerned with catching butterflies on a fine summer evening than they were with
-
saving coal to feed the war machine. The Germans thought daylight saving time would
-
conserve energy. The reasoning goes that it encourages people to stay out later in the
-
summer and thus use less artificial lighting. This sounds logical, and it may have worked
-
back in the more regimented society of a hundred years ago, but does it still work in the modern
-
world? That turns out to be a surprisingly difficult
-
question to answer. For example, take mankind’s greatest invention:
-
AIR CONDITIONING. The magic box of cool that makes otherwise uninhabitable sections of
-
the world quite tolerable places to live. But, pumping heat out of your house isn’t
-
cheap and turning on one air conditioner is the same as running dozens of tungsten light
-
bulbs. If people get more sunshine, but don’t use
-
it to go outside then Daylight Saving Time might actually cost electricity, not save
-
it. This is particularly true in a place like
-
Phoenix: where the average summer high is 107 degrees and the record is 122.
-
If you suggest to an Arizonian to change their clocks in the summer to get more sunshine,
-
they laugh in your face. More sun and higher electricity bills are not what they want which
-
is why Arizona is the second state that never changes their clocks.
-
Another problem when trying to study daylight saving time is rapid changes in technology
-
and electrical use. And as technology gets better and better and
-
better more electricity is dedicated to things that aren’t light bulbs.
-
And the lure of a hot, sweaty, mosquito-filled day outside is less appealing than technological
-
entertainments and climate-controlled comfort inside.
-
Also the horrifically energy in-efficient tungsten light bulbs that have remained unchanged
-
for a century are giving way to CFLs and LEDs – greatly reducing the amount of energy
-
required to light a room. So, even assuming that DST is effective,
-
it’s probably less effective with every passing year.
-
The bottom line is while some studies say DST costs more electricity and others say
-
it saves electricity, the one thing they agree on is the effect size: not 20% or 10% but
-
1% or less, which, in the United States, works out to be about $4 per household.
-
$4 saved or spent on electricity over an entire year is not really a huge deal either way.
-
So the question now becomes is the hassle of switching the clocks twice a year worth it?
-
The most obvious trouble comes from sleep depravation –
-
an already common problem in the western world that DST makes measurably
-
worse. With time-tracking software we can actually
-
see that people are less productive the week after the clock changes. This comes with huge
-
associated costs. To make things worse, most countries take
-
away that hour of sleep on a Monday morning. Sleep depravation can lead to heart attacks
-
and suicides and the Daylight Saving Time Monday has a higher than normal spike in both.
-
Other troubles come from scheduling meetings across time zones.
-
Let’s say that your trying to plan a three-way conference between New York, London and Sydney
-
– not an easy thing to do under the best of circumstances but made extra difficult
-
when they don’t agree on when daylight saving time should start and end.
-
In the spring, Sydney is 11 hours ahead of London and New York is five hours behind.
-
But then New York is the first to enter Daylight Saving Time and moves its clock forward an
-
hour. Two weeks later London does the same. In one more week, Sydney, being on the opposite
-
side of the world, leaves daylight saving time and moves its clock back an hour.
-
So in the space of three weeks New York is five hours behind London, then four hours
-
and then five hours again. And Sydney is either 11, 10 or 9 hours from London and 16,
-
15 or 14 hours from New York. And this whole crazy thing happens again in
-
reverse six months later. Back in the dark ages, this might not have
-
mattered so much but in the modern, interconnected world planning international meetings happens
-
1,000s and 1,000s of times daily – shifting and inconsistent time zones isn’t doing
-
netizens any favors. And, countries aren’t
-
even consistent about daylight saving time within their own borders.
-
Brazil has daylight saving time, but only if you live in the south. Canada has it too,
-
but not Saskatchewan. Most of Oz does DST, but not Western Australia, The Northern Territory
-
or Queensland. And, of course, the United States does have
-
DST, unless you live in Puerto Rico, the Virgin Islands, American Samoa, Guam, the Northern
-
Marianas Islands or, as mentioned before Hawaii and Arizona.
-
But Arizona isn’t even consistent within itself.
-
While Arizona ignores DST, the Navaho Nation inside of Arizona follows it.
-
Inside of the Navaho Nation is the Hopi Reservation which, like Arizona, ignores daylight saving
-
time. Going deeper, inside of the Hopi Reservation
-
is another part of the Navaho Nation which does follow daylight saving time.
-
And finally there is also part of the Hopi Reservation elsewhere in the Navaho Nation
-
which doesn’t. So driving across this hundred-mile stretch
-
would technically necessitate seven clock changes which is insane.
-
While this is an unusual local oddity here is a map showing the different daylight saving
-
and time zone rules in all their complicated glory – it’s a huge mess and constantly
-
needs updating as countries change their laws. Which is why it shouldn’t be surprising
-
that even our digital gadgets can’t keep the time straight occasionally.
-
So to review: daylight saving time gives more sunlight in the summer after work, which,
-
depending on where you live might be an advantage – or not.
-
And it may (or may not) save electricity but one thing is for sure, it’s guaranteed to
-
make something that should be simple, keeping track of time, quite complicated –
-
which is why when it comes time to change the clocks is always a debate about whether or not we should.