It is encouraging that another attempt is being made to change the British time zone so as to increase our use of daylight. It will save energy and reduce road accidents at virtually no cost.
When this was last considered in 2007 I wrote to Sir David King the Scientific Adviser to the Lbour Government as follows:
Dear David
It was good to talk to you - albeit briefly.
You asked for more information on the use of Double Summer Time, particularly as a virtually cost-free method of saving energy. It was used for this purpose in the Second World War (when we were effectively what is now European time) and a trial of just keeping single summer time throughout the year was performed in the UK in 1968 - 1971. The extent of energy saving seems not to be exactly known (at least to me) but the figure of 1% of electricity use is bandied about. That is not an entirely trivial amount. Just think how many wind turbines would be needed to do that - and how much they would cost (in energy as well as money) to build.
It is beyond question that at most times of year except in the two months round the winter solstice, hours of daylight in the early morning are exploited by fewer people than hours of daylight in the evening because we rise and go to sleep according to clock time and not according to sunlight hours. Therefore putting the clocks forward must - and does - reduce energy use. Some people dislike the idea of changing the clocks at all but we are, in any event, committed to this by European directive. So it is only the "time zone" that is in question.
There is also substantial evidence that road accidents are reduced by the change in spite of the fact that some newspapers campaigned shamelessly in 1968-71 by showing pictures of children involved in morning road accidents. Those not involved in the evenings cannot of course be pictured. ROSPA is convinced that the net effect is accident reduction.
I append for you a link to a debate in the House of Lords this spring where Lord Tanlaw proposed to reintroduce "Double summer time". To its shame our (your!) government failed to support the bill and to provide the time for it to be enacted. The Scots are apparently hostile to the idea but now there is devolution they could keep their own time zone and there could then be a proper, controlled trial measuring both energy use and accidents.
I also append some extracts from a web-site giving some US data and an article which gives both sides of the arguments from the student British Medical Journal which is referenced.
I hope you can persuade Ministers that this is really will save some energy and cost nothing - and that you will persuade them to get the Tanlaw bill through parliament this session!
Best wishes
Yours ever
Peter
This year's debate in the House of Lords
http://www.theyworkforyou.com/lords/?id=2006-03-24b.459.0
____________________________________________________________________________________________________________________________________
However, Daylight Saving Time does save energy. Studies done by the U.S. Department of Transportation show that Daylight Saving Time trims the entire country's electricity usage by a small but significant amount, about one percent each day, because less electricity is used for lighting and appliances. Similarly, in New Zealand, power companies have found that power usage decreases 3.5 percent when daylight saving starts. In the first week, peak evening consumption commonly drops around five percent.
Energy use and the demand for electricity for lighting homes is directly related to the times when people go to bed at night and rise in the morning. In the average home, 25 percent of electricity is used for lighting and small appliances, such as TVs, VCRs, and stereos. A good percentage of energy consumed by lighting and appliances occurs in the evening when families are home. By moving the clock ahead one hour, the amount of electricity consumed each day decreases.
In the summer, people who rise before the sun rises use more energy in the morning than if DST was not in effect. However, although 70 percent of Americans rise before 7:00 a.m., this waste of energy from having less sunlight in the morning is more than offset by the savings of energy that results from more sunlight in the evening.
In the winter, the afternoon Daylight Saving Time advantage is offset for many people and businesses by the morning's need for more lighting. In spring and fall, the advantage is generally less than one hour. So, Daylight Saving Time saves energy for lighting in all seasons of the year, but it saves least during the four darkest months of winter (November, December, January, and February), when the afternoon advantage is offset by the need for lighting because of late sunrise.
In addition, less electricity is used because people are home fewer hours during the "longer" days of spring and summer. Most people plan outdoor activities in the extra daylight hours. When people are not at home, they don't turn on the appliances and lights.
There is a public health benefit to Daylight Saving Time, as it decreases traffic accidents. Several studies in the U.S. and Great Britain have found that the DST daylight shift reduces net traffic accidents and fatalities by close to one percent. An increase in accidents in the dark mornings is more than offset by the evening decrease in accidents.
Oil Conservation
Following the 1973 oil embargo, the U.S. Congress extended Daylight Saving Time to 8 months, rather than the normal six months. During that time, the U.S. Department of Transportation found that observing Daylight Saving Time in March and April saved the equivalent in energy of 10,000 barrels of oil each day - a total of 600,000 barrels in each of those two years.
Likewise, in 1986, Daylight Saving Time moved from the last Sunday in April to the first Sunday in April. No change was made to the ending date of the last Sunday in October. Adding the entire month of April to Daylight Saving Time is estimated to save the U.S. about 300,000 barrels of oil each year.
from:http://webexhibits.org/daylightsaving/c.html
________________________________________________________________________________________________________________________________________
When this was last considered in 2007 I wrote to Sir David King the Scientific Adviser to the Lbour Government as follows:
Dear David
It was good to talk to you - albeit briefly.
You asked for more information on the use of Double Summer Time, particularly as a virtually cost-free method of saving energy. It was used for this purpose in the Second World War (when we were effectively what is now European time) and a trial of just keeping single summer time throughout the year was performed in the UK in 1968 - 1971. The extent of energy saving seems not to be exactly known (at least to me) but the figure of 1% of electricity use is bandied about. That is not an entirely trivial amount. Just think how many wind turbines would be needed to do that - and how much they would cost (in energy as well as money) to build.
It is beyond question that at most times of year except in the two months round the winter solstice, hours of daylight in the early morning are exploited by fewer people than hours of daylight in the evening because we rise and go to sleep according to clock time and not according to sunlight hours. Therefore putting the clocks forward must - and does - reduce energy use. Some people dislike the idea of changing the clocks at all but we are, in any event, committed to this by European directive. So it is only the "time zone" that is in question.
There is also substantial evidence that road accidents are reduced by the change in spite of the fact that some newspapers campaigned shamelessly in 1968-71 by showing pictures of children involved in morning road accidents. Those not involved in the evenings cannot of course be pictured. ROSPA is convinced that the net effect is accident reduction.
I append for you a link to a debate in the House of Lords this spring where Lord Tanlaw proposed to reintroduce "Double summer time". To its shame our (your!) government failed to support the bill and to provide the time for it to be enacted. The Scots are apparently hostile to the idea but now there is devolution they could keep their own time zone and there could then be a proper, controlled trial measuring both energy use and accidents.
I also append some extracts from a web-site giving some US data and an article which gives both sides of the arguments from the student British Medical Journal which is referenced.
I hope you can persuade Ministers that this is really will save some energy and cost nothing - and that you will persuade them to get the Tanlaw bill through parliament this session!
Best wishes
Yours ever
Peter
This year's debate in the House of Lords
http://www.theyworkforyou.com/lords/?id=2006-03-24b.459.0
____________________________________________________________________________________________________________________________________
However, Daylight Saving Time does save energy. Studies done by the U.S. Department of Transportation show that Daylight Saving Time trims the entire country's electricity usage by a small but significant amount, about one percent each day, because less electricity is used for lighting and appliances. Similarly, in New Zealand, power companies have found that power usage decreases 3.5 percent when daylight saving starts. In the first week, peak evening consumption commonly drops around five percent.
Energy use and the demand for electricity for lighting homes is directly related to the times when people go to bed at night and rise in the morning. In the average home, 25 percent of electricity is used for lighting and small appliances, such as TVs, VCRs, and stereos. A good percentage of energy consumed by lighting and appliances occurs in the evening when families are home. By moving the clock ahead one hour, the amount of electricity consumed each day decreases.
In the summer, people who rise before the sun rises use more energy in the morning than if DST was not in effect. However, although 70 percent of Americans rise before 7:00 a.m., this waste of energy from having less sunlight in the morning is more than offset by the savings of energy that results from more sunlight in the evening.
In the winter, the afternoon Daylight Saving Time advantage is offset for many people and businesses by the morning's need for more lighting. In spring and fall, the advantage is generally less than one hour. So, Daylight Saving Time saves energy for lighting in all seasons of the year, but it saves least during the four darkest months of winter (November, December, January, and February), when the afternoon advantage is offset by the need for lighting because of late sunrise.
In addition, less electricity is used because people are home fewer hours during the "longer" days of spring and summer. Most people plan outdoor activities in the extra daylight hours. When people are not at home, they don't turn on the appliances and lights.
There is a public health benefit to Daylight Saving Time, as it decreases traffic accidents. Several studies in the U.S. and Great Britain have found that the DST daylight shift reduces net traffic accidents and fatalities by close to one percent. An increase in accidents in the dark mornings is more than offset by the evening decrease in accidents.
Oil Conservation
Following the 1973 oil embargo, the U.S. Congress extended Daylight Saving Time to 8 months, rather than the normal six months. During that time, the U.S. Department of Transportation found that observing Daylight Saving Time in March and April saved the equivalent in energy of 10,000 barrels of oil each day - a total of 600,000 barrels in each of those two years.
Likewise, in 1986, Daylight Saving Time moved from the last Sunday in April to the first Sunday in April. No change was made to the ending date of the last Sunday in October. Adding the entire month of April to Daylight Saving Time is estimated to save the U.S. about 300,000 barrels of oil each year.
from:http://webexhibits.org/daylightsaving/c.html
________________________________________________________________________________________________________________________________________
Clockwatching
Impress your mates at the pub with your startling repertoire of esoteric medical knowledge
What happens this year on 26 March in Europe, is delayed until 2 April in America, but doesn't occur in Japan at all? Well, in those countries taking part, it's time to turn the clocks forward one hour, marking the start of daylight saving time (DST), or summer time as it's also known. Now you might groan about losing valuable minutes for partying, studying, or sleeping (your priorities changing as you progress through the course), but are there any tangible benefits to this annual ritual? And what about the health implications of daylight saving that don't often get a mention?
Origins
Benjamin Franklin came up with the bright idea in 1784, to make better use of daylight and so reduce the amount of money wasted on candles in 18th century Paris.w1 By having the population rise at dawn and go to bed at sunset, as well as rationing candle sales and putting a tax on houses with shutters, he estimated (not entirely seriously) that anywhere between �150m and �400m in today's money could be saved.
The idea didn't resurface until 1907 when a London builder, William Willett, advocated advancing the clocks by 20 minutes on each Sunday in April and reversing the process in September.w2 It found limited support until the first world war, when Britain, Germany, and other countries adopted daylight saving in 1916 to boost wartime production and save coal. The US followed suit for seven months in 1918, but public opposition led to Congress overriding the measure against the wishes of President Woodrow Wilson�it wasn't until the second world war that Franklin Roosevelt introduced it again across America. At the same time in the UK, political enthusiasm for the energy savings associated with DST led to the introduction of double summer time for the duration of the war, whereby the clocks were advanced two hours ahead of Greenwich Mean Time (GMT) in the summer and stayed an hour ahead of GMT for the rest of the year.
Fast-forward to today, and roughly 70 countries have daylight saving time, although when it starts, how long it lasts and how much of each country is affected varies widely.
Benefits
Accident reduction
A reduction in fatal road traffic accidents is often cited as the major public health benefit of daylight saving time. When Great Britain experimented with maintaining DST all year round between 1968 and 1971, it's thought about 2,500 fewer people were killed or seriously injured during the first two winters of the trial�the equivalent of an 11.7% reduction in casualties for the whole country. Although morning casualties increased, the number was far outweighed by the drop in casualties in the longer evenings.w3 Smaller studies in the UK have confirmed this trend, with improvements in safety primarily for pedestrians, cyclists, and school children.w4 w5 More recently, the Royal Society for the Prevention of Accidents has estimated that 450 deaths and serious injuries occur during the five months of the year when DST is not in operation in the UK.w6 In the US, the Insurance Institute for Highway Safety estimated that 901 fatal crashes could have been prevented over the years 1987-91 if DST had been retained year round due to the availability of an extra hour of daylight for the busier evening traffic rush.w7
Unfortunately �unambiguous� and �evidence� rarely go together. The three year British trial of DST coincided with the introduction of random breath testing and new speed limits�powerful incentives for drivers to improve their behaviour regardless of how bright the evening is. Studies have shown an increase in road accidents during the first few days of DST (by as much as 8%)w8 and unexpectedly following the end of DSTw9 which are attributed diversely to loss of an hour's sleep, alcohol, fatigue, and the fact that the early morning period is intrinsically risky.
Energy savings
Just as importantly for the planet, using daylight more efficiently could mean modest but significant energy savings and reduced pollution. As a result of the Arab oil embargo in the 1970s, the US Congress experimented with extended DST for two years (18 months over that period instead of the normal 12).
When the US Department of Transport evaluated the effectiveness of the trial, it found that roughly 100000 barrels of oil were saved daily in March and April of 1974 and 1975 by having DST.w10 Extending this finding, energy stricken California estimates that an extension of DST for the winter months could reduce electricity use by 0.5%.w11 These savings are mainly due to reduced domestic consumption thanks to the extra hour of daylight in the evenings.
However, before we rush to adjust our clocks, a senior official in the US Department of Transport recently
sounded a note of caution: �There have been dramatic changes in lifestyle and commerce since we completed our studies that raise serious questions about extrapolating conclusions from our studies into today's world.�w10
She emphasised that their work is over 25 years old, was limited in scope, and has had its methods questioned (for example, failing to consider that reduced electricity use could be offset by increased petrol consumption owing to extra evening travel)w12�so we haven't found an alternative to Kyoto just yet.
General wellbeing
Claims have been made that brighter evenings would increase our exposure to daylight and encourage outdoor activity, fitness and health. Supporters of extended DST also maintain that more time spent in the sunlight would reduce vitamin D deficiencies, especially in children and elderly people, and help people with depressionw13 and seasonal affective disorder (SAD)�a specific type of depression believed to be related to reduced exposure to sunlight.w14 As low vitamin D levels are a problem for 6-18% of the elderly US population,w15 rocketing to 57% of the general inpatient population,w16 and with anywhere up to 500000 suffering from SAD in the UK alone,w17 the public health benefits of DST could be far-reaching but have not been proved.
Exceptions to benefits
Nevertheless, although we might agree that all these �benefits are worth while, our bodies beg to differ when actually faced with the change. Circadian rhythms, our own biological clocks, regulate behavioural and physiological processes and are synchronised by the daily light-dark cycle. Changing over to DST in the spring is thought to upset this cycle in healthy adults who get less than eight hours sleep (most medics) or are more active in the evenings,w18 and disruption is also seen for five days after DST ends.w19 Those few transition days are particularly difficult for anyone with depression20 as well as teenagers and adolescents, whose body clocks are already poorly synchronised to daylight thanks to delayed secretion of melatonin, the body's �sleepiness� hormone.w21 All in all, the only ones enjoying changeover day itself will probably be those irritating individuals who have never missed a night's sleep and finish a day's work before the rest of us are even out of bed, but, to quote Oscar Wilde, �Only dull people are brilliant at breakfast.�
Conclusion
Despite mixed reports, governments look set to continue tinkering with the issue. George Bush, mindful of his country's addiction to oil, has extended DST in the US by a month, starting in 2007. In the UK, frustrated by a decade of government dithering, the Royal Society for the Prevention of Accidents has called for DST to be in place throughout the winter, with double summer time from March to October (two hours ahead of GMT); a throwback to the war years, this would have the effect of abolishing GMT, putting the UK in the same time zone as western Europe.w14 While some will be quick to criticise any possibility of change, a chance that hundreds of road traffic accidents could be prevented means that the plans deserve a fair hearing at the very least; whether they will be implemented is a different matter.
Thomas Mac Mahon , intercalating medical student, University College Dublin, IrelandEmail: tmacmahon@gmail.com
studentBMJ 2006;14:133 - 176 April ISSN 0966-6494
from: http://www.studentbmj.com/issues/06/04/education/144.php
- Franklin, B., "An Economical Project: Daylight Saving." A letter to the editor of the Journal de Paris April 26, 1784 http://webexhibits.org/daylightsaving/franklin3.html (accessed February 10, 2006)
- Franklin, B., "An Economical Project: Daylight Saving." A letter to the editor of the Journal de Paris April 26, 1784 http://webexhibits.org/daylightsaving/franklin3.html (accessed February 10, 2006)
- Home Office, "Review of British Standard Time," Cmnd 4512: HMSO, 1970
- Whittaker, J.D., "An investigation into the effects of British Summer Time on road traffic accident casualties in Cheshire," J Accid Emerg Med 13 (1996): 189-92
- Adams, J., White, M., Heywood, P., "Year-round daylight saving and serious or fatal road traffic injuries in children in the north-east of England," J Public Health (Oxf) 27 (2005): 316-7
- Royal Society for the Prevention of Accidents. Lighter Evenings: RoSPA summertime briefing. Birmingham, 2005 http://www.rospa.com/roadsafety/info/summertime_briefing.pdf (accessed February 10, 2006)
- Ferguson, S.A., et al., "Daylight saving time and motor vehicle crashes: the reduction in pedestrian and vehicle occupant fatalities," Am J Public Health 85 (1995): 92-5
- Coren, S., "Accidental death and the shift to daylight savings time," Percept Motor Skills 83 (1996): 921-2
- Varughese, J., Allen, R.P., "Fatal accidents following changes in daylight savings time: the American experience," Sleep Med 2 (2001): 31-6
- U.S. Department of Transportation. The Daylight Saving Time study. A report to Congress. Washington, GPO, 1975. Cited by: L.L. Lawson, Acting Deputy Assistant Secretary for Transportation Policy, appearing before the House Science Committee, Energy Subcommittee, concerning daylight saving time and energy conservation, May 24, 2001 http://www.house.gov/science/energy/may24/lawson.htm (accessed February 10, 2006)
- Kandel, A., Metz, D., "Effects of Daylight Saving Time on California Electricity Use," California Energy Commission, May 2001 http://www.energy.ca.gov/reports/2001-05-23_400-01-013.PDF (accessed February 10, 2006)
- Tellier-Beauregard, F., "PRB 05-18E Daylight saving time and energy conservation," Parliamentary Research and Information Service, Parliament of Canada. July 29, 2005 http://www.parl.gc.ca/information/library/PRBpubs/prb0518-e.htm#2txt (accessed February 10, 2006)
- Olders, H., "Average sunrise time predicts depression prevalence," J Psychosom Res 55 (2003): 99-105
- Royal Society for the Prevention of Accidents. Single/Double Summer Time: Position Paper. Birmingham, 2003 (updated 2005). http://www.rospa.com/roadsafety/info/summertime_paper.pdf (accessed February 10, 2006)
- http://whqlibdoc.who.int/publications/2004/9241546123_chap3.pdf (accessed February 10, 2006)
- Thomas, M.K., et al., "Hypovitaminosis D in medical inpatients," N Engl J Med 338 (1998): 777-83
- Seasonal Affective Disorder Association http://www.sada.org.uk/ (accessed February 10, 2006)
- Lahti, T.A., et al., "Transition into daylight saving time influences the fragmentation of the rest-activity cycle," J Circadian Rhythms 19 (2006): 1 [Epub ahead of print]
- Monk, T.H., Folkard, S., "Adjusting to the changes to and from Daylight Saving Time," Nature 261 (1976): 688-9
- Bunney, W.E., Bunney, B.G., "Molecular clock genes in man and lower animals: possible implications for circadian abnormalities in depression," Neuropsychopharmacology 22 (2000): 335-45
- Carskadon, M.A., et al., "Regulation of adolescent sleep: implications for behaviour," Ann N Y Acad Sci 1021 (2004): 276-91
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