Don’t Forget To Set Clocks Back An Hour Sunday November 06, 2011

Time for change? GMT could be history

Leading scientists from around the world are meeting from Thursday to consider a proposal that could eventually see Greenwich Mean Time relegated to a footnote in history.

For more than 120 years GMT has been the international standard for timekeeping, but it is now under threat from a new definition of time itself based not on the rotation of the Earth, but on atomic clocks.

Early adoption in law

Daylight Saving Time has been used in the U.S. and in many European countries since World War I. At that time, in an effort to conserve fuel needed to produce electric power, Germany and Austria took time by the forelock, and began saving daylight at 11:00 p.m. on April 30, 1916, by advancing the hands of the clock one hour until the following October. Other countries immediately adopted this 1916 action: Belgium, Denmark, France, Italy, Luxembourg, Netherlands, Norway, Portugal, Sweden, Turkey, and Tasmania. Nova Scotia and Manitoba adopted it as well, with Britain following suit three weeks later, on May 21, 1916. In 1917, Australia and Newfoundland began saving daylight.

The plan was not formally adopted in the U.S. until 1918. ‘An Act to preserve daylight and provide standard time for the United States’ was enacted on March 19, 1918. [See law]It both established standard time zones and set summer DST to begin on March 31, 1918. Daylight Saving Time was observed for seven months in 1918 and 1919. After the War ended, the law proved so unpopular (mostly because people rose earlier and went to bed earlier than people do today) that it was repealed in 1919 with a Congressional override of President Wilson’s veto. Daylight Saving Time became a local option, and was continued in a few states, such as Massachusetts and Rhode Island, and in some cities, such as New York, Philadelphia, and Chicago.

During World War II, President Franklin Roosevelt instituted year-round Daylight Saving Time, called “War Time,” from February 9, 1942 to September 30, 1945. [See law] From 1945 to 1966, there was no federal law regarding Daylight Saving Time, so states and localities were free to choose whether or not to observe Daylight Saving Time and could choose when it began and ended. This understandably caused confusion, especially for the broadcasting industry, as well as for railways, airlines, and bus companies. Because of the different local customs and laws, radio and TV stations and the transportation companies had to publish new schedules every time a state or town began or ended Daylight Saving Time.

On January 4, 1974, President Nixon signed into law the Emergency Daylight Saving Time Energy Conservation Act of 1973. Then, beginning on January 6, 1974, implementing the Daylight Saving Time Energy Act, clocks were set ahead. On October 5, 1974, Congress amended the Act, and Standard Time returned on October 27, 1974. Daylight Saving Time resumed on February 23, 1975 and ended on October 26, 1975.

Inconsistent use in the U.S.

In the early 1960s, observance of Daylight Saving Time was quite inconsistent, with a hodgepodge of time observances, and no agreement about when to change clocks. The Interstate Commerce Commission, the nation’s timekeeper, was immobilized, and the matter remained deadlocked. Many business interests were supportive of standardization, 

In January 2012, the International Telecommunication Union will meet in Geneva to vote on whether to adopt the new measure, despite protests from Britain.

The two-day meeting of about 50 experts at a country house northwest of London, under the aegis of the prestigious Royal Society, on Thursday and Friday will look at some of the issues involved.

Predictably the question has hurt national pride — particularly when British believe their old rivals France are leading the push to change away from GMT to the new time standard.

“We understand that in Britain they have a sense of loss for GMT,” said Elisa Felicitas Arias, director of the time department at the France-based International Bureau of Weights and Measures (BIPM), which pushed for the change.

GMT is based on the passage of the sun over the zero meridian line at the Greenwich Observatory in southeast London, and became the world standard for time at a conference in Washington in the United States in 1884.

France had lobbied for “Paris Mean Time” at the same conference.

In 1972 it was replaced in name by Universal Coordinated Time (UTC) but that essentially remained the same as GMT.

UTC is based on about 400 atomic clocks at laboratories around the world but then corrected with “leap seconds” to align itself with the Earth’s rotational speed, which fluctates.

But the tiny variations between Earth speed and atomic speed have become a problem for GPS, the global positioning systems and mobile phone networks on which the modern world relies.

“These networks need to be synchronised to the millisecond,” Arias said.

The meeting in London will look at the implications of abolishing the leap seconds and moving fully to atomic time.

That would see atomic time slowly diverge from GMT, by about one minute every 60 to 90 years, or by an hour every 600 years, and there would need to be “leap minutes” a couple of times a century to bring the two in line.

The proposal would then formally be voted on in Geneva.

The potential loss of GMT has prompted soul searching in the British press, particularly at a time when the country is itself considering switching to British Summer Time, one hour ahead of GMT, on a permanent basis.

The Sunday Times said GMT had “symbolised Britain’s role as a Victorian superpower” but that “just as that role has inexorably diminished, so GMT itself could in effect disappear.”

Science minister David Willetts has opposed the plan, saying it has become more than just a scientific row.

“This is primarily a finely balanced scientific argument but I do detect undercurrents of nationalism,” he said.

“Britain’s position is that we should stick to real time as experienced by humans, which is based on the Earth’s rotation, not atomic clocks.

“Without leap seconds we will lose contact with the reality of Earth’s rotation. Eventually our midnight would happen at noon.”more

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