

Daylight saving time by country. Blue means "Northern hemisphere summer time" is used, while orange means "Southern hemisphere summer time" is used. Dark gray is countries who have never used DST, while light gray means they once used it but do not any longer. (TimeZonesBoy/Wikipedia)

On Sunday morning, Americans awoke to an extra hour, the result of the country's adherence to daylight saving time. With it came a reignited debate. Wonkblog's Chris Mooney was among those who criticized the practice, writing that "turning our clocks back Sunday makes no sense," and argued that the original logic that made America switch to daylights saving time was flawed.

Whatever you think of America's daylight savings debate, it's a useful reminder that the time we set our clocks to are not set in stone. It's decided upon by politicians — and all around the world, it causes controversy.

For a start, while more than 70 countries use some form of daylight saving time (it is particularly popular in North America and Western Europe), the rest of the world doesn't. And among those countries that do use it, there are some strange, unexplainable differences: In Europe, for example, clocks are changed on the last Sunday of March and on the last Sunday of October, one week earlier than the U.S.

Those countries that regularly change their clocks often debate the logic of doing so. In Britain, for instance, the changing of the clocks has led to some quite significant controversy. One idea put forward by environmental groups has become known as "Single/Double Summer Time," and would require the U.K. to keep its clocks in "summer time" during winter. The clocks would then go forward one extra hour in summer, for what would be known as "double summer time."

The U.K. has come fairly close to changing its policy. In 2010, one politician put forward a bill that would have required the government to investigate whether moving the clock forward for part of or all of the year was actually beneficial to the country. It proved remarkably controversial, and while the bill saw some backing from Prime Minister David Cameron, it did not make it past the House of Commons before the allocated time and thus was abandoned.

Other countries that have used daylight saving in the past have turned their back on it. In 2011, Russia's then-President Dimitry Medvedev pushed through a plan to end the practice in Russia, which the country had observed since the Soviet era, and shift to permanent summer time. Medvedev cited a medical report that said that the number of heart attacks increase by 1.5 times and the rate of suicides grows by 66 percent in the period when clocks were changed.

However, there were problems. Some residents complained that it meant that the sun would be rising at 9 a.m. in certain locations. Angry lawmakers cited health data that suggested that the time change was causing damage to Russians' health. In July, Vladimir Putin, who had returned to the president's office, announced that Russia would do away with permanent summer time. Instead, Russia would go to permanent winter time.

It was a politically notable event. Putin had in effect destroyed one of the few real legacies of his protege Medvedev's time in office. And along with the move to winter time, Putin also announced that he would reintroduce two time zones that had been removed by Medvedev, pushing the country's total number of time zones from nine to 11.



Time zones around the world, as of October 2014. (TimeZonesBoy/Wikipedia)

Time zones may be an even more politically charged subject than daylight saving. While Russia may have the most time zones of any country in the world, a symbol of its grandiosity, other large countries don't bother with them at all. In 1918, for example, the nascent Republic of China established five time zones. However, in 1949, the new Communist government decided to reverse this: The entire country would have one time zone, and clocks would be set to Beijing time.

This causes some pretty obvious problems for cities far from Beijing. "In the summer, for instance, it isn’t uncommon in Ürümqi, Xinjiang's capital, to see people enjoying a beautiful sunset ... at midnight," Matt Schiavenza noted in the Atlantic last year. In practice, many in China's far west adopt an informal "Ürümqi Time."

China is not alone. India, another large country, has a single time zone, creating similar problems. In that country, some are now challenging the time zone hierarchy: Earlier this year, Assam, a northeastern Indian state, announced plans to shift its clocks one hour forward.

As my colleague Ishaan Tharoor has pointed out, this probably has a lot to do with nation building: Benedict Anderson, a leading modern theorist, listed the clock as one of the two most important inventions for modern European state-building (the other was the newspaper). By having one time zone in China and India, you strongly strengthen the idea that these are single nations with a unified people. It's worth noting that after Crimea voted to become part of Russia this year, it changed its time zone to Moscow time.

As problematic as such a practice might seem, the reality is that most of the world's time zones are "wrong" to some degree or another. Take a look at the map below, charted by Google engineer Stefano Maggiolo, which shows how far off some of the world's time zones are from what they should be, according to solar time.



The difference between solar time vs official time (Stefano Maggiolo)

As you can see, it's not just India and China who have some time zone issues: Virtually every nation does. Some of these are understandable — Argentina, which has significant economic ties with Brazil, follows the same time zone as the big cities in Brazil's east rather than the sparsely populated Brazilian regions. But why is the Russian city of Vladivostok, just north of Japan, two hours behind Japan?

So, perhaps America's adherence to daylight saving time doesn't make sense. Perhaps, the country should move to two time zones instead (one widely floated idea). But it's worth remembering that such a decision will no doubt be political and controversial. And evidence suggests that any way we do it, it may be imperfect.