Saving daylight

In my considered opinion, setting the times for the start and end of Daylight Savings Time (DST) should be a federal government responsibility. Australia should join with most of the rest of the developed world and observe at least six months of DST, and preferably 7-8 months; and Australia's time zones should be brought up to the 21st century, instead of languishing in the 19th century. Let me explain.

The only other countries that comprise a federation of states or provinces and that span multiple time zones are the United States and Canada. In the US, setting the dates for the beginning and ending of DST is a federal government responsibility, as it should be, because it impacts significantly on interstate and international trade, as well as other issues beyond state responsibilities.

Provinces in Canada have opted (with the exception of Saskatchewan) to follow the US in observing the beginning and ending of DST, effectively making it a federal decision, although the provinces retain the right to make their own decisions, if they choose.

Leaving the responsibility with the states is an invitation to chaos, and certainly gives rise to the anomaly in Australia, where Tasmania starts DST a month earlier than any other state.

The states and territories should have the right to decide whether or not to adopt DST, but should then be required to change clocks on the federally determined dates. The US federal law that sets daylight time does not require any area to observe daylight saving time, but does require that any area choosing to observe DST must follow the starting and ending times set by federal law.

Second, Australia, while priding itself on being an outdoors oriented nation, observes DST for a shorter time than any other nation that observes DST. Apart from Tasmania, we observe DST for just five months. Most nations in the northern hemisphere that observe DST do so for at least six months, and most do so for seven or eight months.

Logic would suggest that, if it is the length of daylight hours that is at issue, then we should start and end DST at times that are equal relative to the Equinoxes on March 22 and September 22, when there are exactly 12 hours of daylight. Admittedly, few countries do so. However, we currently do not change to DST until about six weeks after the Spring Equinox, when the day is already much longer than 12 hours, but we end DST about a week after the Autumn Equinox, when the day is already a little less than 12 hours.

As a result, we had the situation this year where, on the day before we changed the clocks, sunrise occurred at 4.59am in Sydney. Logic would suggest that, instead of changing the clocks at the end of October, we should change them in mid-September, when the length of daylight hours is the same as at the end of March. Better yet would be to begin DST at the end of August, and end it at the end of April, giving eight months of DST and four months on standard time.

Experience in other countries suggests that starting DST earlier and ending it later would have beneficial effects on air quality, energy use, and road safety, to name but a few of the advantages.

A 1975 study by the US Department of Transportation showed that extending DST from starting in April to starting in March would save about 1 per cent of the nation's electricity use. Furthermore, when the US extended DST in 1974 and 1975 as a result of the 1973 energy crisis, the US DOT found that observing DST in March and April saved 10,000 barrels of oil a day and prevented about 2,000 traffic injuries and 50 traffic fatalities in the period, representing a traffic cost savings at that time of US$28 million.

There are also expected benefits of crime reduction, although these have not been estimated quantitatively. For that matter, many people who, like the author of this piece, find it frustrating to have the dawn occurring well before 6am in the Spring, would no longer have that frustration.

There are also potential benefits to international business. During periods of DST, Australia has a smaller difference in time with the United States and Canada. As a result, when Australia observes more days and weeks of DST, there is more opportunity for business contact during the working day. Because of the larger time difference with Europe and the UK, changes to DST will basically not affect trading with those areas of the world.

Third, Australia should reconsider its time zones. Current time zones are based on solar time - the idea that noon is when the sun is overhead. In the 19th century, before artificial lighting was widely available, this made reasonable sense. People rose with the dawn and went to bed after dusk, with most work being done in the hours of daylight.

However, long ago, Europe recognised that this was no longer sensible, and that noon does not mark the middle of the day in 20th or 21st century life. Indeed, most people probably get up at about 6am and go to bed at about 10.30 or 11pm, so that the middle of the day is actually nearer to 2pm.

Instead of clinging to the anachronistic idea of the sun being overhead at midday, it would make more sense to advance time by an hour or so across Australia, as a part of standard time.

Australia also has a half-hour time change, which is also quite awkward in this day and age of frequent interstate travel, especially since most of South Australia and the Northern Territory is an hour different by the sun from the east coast of the country. Each one hour of solar time represents a 15 degree change in longitude. There is a 13 degree difference between Adelaide and Sydney, so Adelaide should be one hour different from Sydney.

My proposal on time zones is that the time should be advanced one hour for the eastern time zone, one half hour for the central time zone and one hour for the western time zone. This would put an end to the half hour time difference, and would also move the middle of the daylight period to about 1pm for much of populated Australia.

What would be the implications of this?

Currently in Sydney, the sun rises at about 7.01am from June 22 until July 8 (the latest sunrise). Under my proposal, this would now be at about 8.01am, with it becoming light at about 7.30am. At that time, the sun would set at about 5.55pm, instead of the current 4.55pm.

In mid summer, the sun currently rises at 4.37am from December 1 until December 10. This would become 5.37am on standard time, or 6.37am on DST. The latest sunset is about 7.10pm from January 1 until January 14, and would be at 8.10pm standard time or 9.10pm DST.

These times are all eminently reasonable for the beginning and ending of daylight on days in the winter and summer.

Now consider the effects of starting DST earlier and ending it later.

Currently, apart from Tasmania, we start DST at the end of October, when sunrise in Sydney is around 5am and sunset is around 6.20pm. We end DST at the end of March when sunrise is around 6.55am (DST) and sunset is around 6.50pm (DST).

To match the sunrise and sunset times that we have at the end of DST with the beginning would require changing to DST on or about September 15. These would then change to 6.55am and 6.40pm almost an identical match to the end of March.

This would provide just over six months of daylight saving time. In 2007, for one time, the end of DST is to be delayed until the first weekend in April. At that time, sunrise will be about 7.10am and sunset at 6.45pm in Sydney, changing to 6.10 and 5.45 respectively after the clocks change. The same sunrise and sunset would occur at the very beginning of September. This would suggest that a better situation might be to change the clocks at the beginning of September and the beginning of April. This would be easy to remember and very logical in terms of the length of daylight.

The combined effects of the time zone change and DST changes are shown for Sydney, Adelaide, Brisbane and Perth in Table 1.

This would have some useful effects. First, the time difference between Sydney and New York would be nine hours in mid-June, but would be eight hours from the beginning of September, and seven hours from the beginning of November (when the US returns to standard time from 2007). It would remain at seven hours until the US begins DST in March (from 2007), when it would change to eight hours and to nine hours when Australia ends DST at the beginning of April.

In summary, it is my opinion that the federal government in Australia should be responsible for setting the dates for beginning and ending DST; that those dates should be moved back to September or end of August for the beginning and to the beginning or end of April for ending DST; that the individual states and territories should have the right to decide if they will observe DST or not; and that the time zones in Australia should be changed to advance the eastern time zone by one hour, the central time zone by a half hour, and the western time zone by one hour.