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Doc. 8564

6 October 1999

Observance of the system of European time zones


Committee on the Environment, Regional Planning and Local Authorities

Rapporteur : Mr Jean Briane, France, Group of the European People's Party


In several European countries, the legal time does not always correspond to the time of the zone they belong to. The difference can exceed two hours in some regions.

This difference and the displacement of daily rhythms with respect to solar time could be the cause of certain phenomena that affect the environment, health and the human physiological and psychological condition.

The Assembly is of the opinion that observance of the system of time zones could help to reduce the damage to the environment and health, and recommends that the Committee of Ministers take an initiative in this direction.

I.       Draft recommendation

1. The legal time set by each country according to its geographical location is one of the essential reference points around which all society’s activities are organised.

2. The Assembly recalls that in accordance with the Washington Treaty (1884) which introduced the system of co-ordinated universal time (UTC), the territory of Europe (excluding the Russian Federation) is in 3 time zones. For its part, the Russian Federation covers several time zones.

3. It notes however that as a result of different measures decided at national level, the legal time in European countries is not always that of their respective time zones.

4. First, in order to achieve energy savings and make the best use of daylight, several countries introduced a legal time one hour ahead of their time zone. Certain countries, including the United Kingdom, Ireland, Portugal, Estonia, Latvia, Lithuania, Belarus, Ukraine and Moldova, subsequently gave up this measure; others such as Belgium, France, Luxembourg, the Netherlands and Spain, still apply it today.

5. Second, again to save energy and make the best use of natural light, around the early 80s the majority of European countries adopted what is known as summer time, which consists of putting the clock forward one hour for the summer period.

6. In this connection, the Assembly is pleased that, as it advocated in its Recommendation 801 (1977), the change to summer time and back to winter time takes place in harmonised fashion in all of the European countries that apply it.

7. However, it notes that in those countries that apply summer time while also maintaining the legal time permanently one hour ahead of the time zone, namely Belgium, France, Luxembourg, the Netherlands and Spain, the difference between the legal time and solar time can exceed two hours in summer, creating the situation of "double summer time".

8. According to some recent scientific research and observations, this substantial difference and the resulting displacement of daily rhythms with respect to solar time are, in these countries, at the origin of certain phenomena that affect the environment, health and the human physiological and psychological condition.

9. They contribute for example to a greater concentration in the air of photochemical oxidants (including ozone and peroxyacetyl nitrate), which has serious consequences not only for the health of people vulnerable to toxic substances, but also for the natural and cultural heritage.

10. The observations conducted in these countries show that the considerable difference in the rhythm of life with respect to the solar cycle which results from double summer time provokes in many individuals, especially children and elderly people, difficulty in sleeping and hence inadequate nocturnal rest, which in turn has effects on their general condition, physical balance and intellectual performance.

11. In these countries that have double summer time, other negative effects can be seen in different fields of occupational and social activity, while the advantages that it brings, including the energy savings, are uncertain or even open to question.

12. As a result, the present time system is unpopular with a substantial part of the population of these countries, and indeed of certain others, all the more so because its introduction has never been legitimised by any democratic procedure.

13. The Assembly is therefore of the opinion that bringing the legal time of these countries, namely Belgium, France, Luxembourg, the Netherlands and Spain, into line with the standard time of the time zone to which they belong geographically, even with the retention of the arrangements relating to summer time, would have positive effects on the level of atmospheric pollution and the health and well-being of the population.

14. The Assembly considers that the coherence and harmonisation of the legal time systems of the European countries plays an important role in the development of trade and the promotion of Europe’s economic and social cohesion.

15. It also recognises that the alignment of the countries concerned, namely Belgium, France, Luxembourg, the Netherlands and Spain, with the time kept by their neighbours of the East facilitates contacts and communications between them, while regretting that this creates for the populations of the former countries situations of inequality in terms of pollution and of comfort of life.

16. It recalls however that countries of continental dimension, such as the United States, Canada, Australia and the Russian Federation, are divided into several time zones without this perturbing the cohesion of their respective territories nor the functioning of their economies and institutions or the everyday life of the population or their relations with the rest of the world.

17. In Europe itself, and in particular in the European Union, the existence of time zones does not constitute an obstacle to co-operation between the countries belonging to different zones.

18. The Assembly therefore considers that the respect by all European countries of the standard time of their time zone would not create insurmountable difficulties for European integration.

19. The Assembly therefore recommends that the Committee of Ministers:

i.       invite the governments of member states where double summer time exists, namely Belgium, France, Luxembourg, the Netherlands and Spain, to consider the re-establishment in winter of a legal time corresponding to their respective time zone, in the respect of democratic procedures and in consultation with the organisations representing the different branches of activity and civil society and taking account of all the relevant aspects, in particular those concerning:

      a. the increased pollution of the air by photochemical oxidants and its consequences for health,

      b. the disruption of the biological rhythms of a large part of the population and the resulting physiological and psychological problems,

      c. the effect on the working conditions and family and social life of workers dependent on natural cycles;

ii.       to invite the governments of all member states to organise objective and comprehensive studies on all the advantages and disadvantages resulting from the application of summer time in order to decide together, in the respect of sovereignty and of democratic principles, on the expediency of retaining this measure.

II.       Explanatory memorandum by the Rapporteur


1.       Introduction

      - General background

- Washington Treaty

      - Historical development of standard time in Europe

      - Double summer time

      - Context of the report

      - Sources

2.       Consequences of double summer time

      - Air pollution

      - Public health and wellbeing

      - Other consequences

      - Public opinion

      - Decision-making procedure

      - Competence for decision-making

3.       Conclusions and proposals

Appendix :

European Time Zones

1.       Introduction

1. For ages, human beings have organised their activities and lives around the annual, seasonal and daily rhythms of nature, which are governed by solar cycles. The changing seasons over the year and the alternation of day and night are objective and self-evident facts which human beings took some time to understand, but which they have never pretended to ignore nor, still less, thought able to alter.

2. No one has yet considered of shifting the seasons, as the absurdity of such an undertaking is too obvious. However, experimenting with time seems to be less impossible, and the twentieth century has offered some examples in this area, the most recent being the system of “summer time” which we now have in Europe.

3. This system, which involves putting the clocks one or two hours forward during the “summer” period, is popular in some countries and unpopular in others. As, however, is always the case when we attempt to manipulate the laws of nature, it has an impact on certain natural mechanisms that ultimately determine the state of the environment and human wellbeing.

General background

4. Nature’s daily rhythm is based almost without exception on the solar cycle – the natural world awakes after sunrise, is active during daylight, quietens down again after sunset and sleeps during darkness. Quite naturally, the functioning of the human body and the rhythm of our activities are also more or less precisely determined by the sun as the primary source of time.

5. In addition, it is the solar cycle that is used to set the clocks that determine artificial time, midday being the time when the sun is at its highest point above the horizon.

6. Obviously, solar midday does not occur at the same time in places at different longitudes. However, human society cannot function smoothly unless the same time is observed throughout a given territory, which is why “standard time” was introduced.

Washington Treaty

7. In addition, in order to harmonise the standard times observed in the various regions of the world, a system of “universal time co-ordinated (UTC)” was adopted at the Washington Conference in 1884. The globe was divided into 24 time zones of 15o longitude corresponding to the 24 hours of the day, the starting point being set at the 0o meridian (Greenwich Mean Time or GMT). Depending on their situation and size, all countries therefore found themselves in one or other or several of these time zones.

8. Although some adjustments have been made, this system of subdivision still applies in continental-sized countries such as the United States, Canada, Russia and Australia.

9. The territory of Europe (excluding the Russian Federation) is in 3 time zones – Western European Time or GMT (United Kingdom, Ireland, the Netherlands, Belgium, Luxembourg, France, Andorra, Spain, Portugal); Central European Time or GMT + 1 ( most Central European countries ); and Eastern European Time or GMT + 2 (Finland, Estonia, Latvia, Lithuania, Belarus, Ukraine, Moldova, Romania, Bulgaria, Greece, Turkey, Cyprus).

Historical development of standard time in Europe

10. During the first world war, several countries decided to take greater advantage of daylight, and thus save on the cost of lighting, by moving their clocks forward an hour in summer and returning to their local meridian time in winter. This arrangement continued in some countries until the outbreak of the second world war, during which the occupied countries had Berlin time imposed on them and thus ended up two hours ahead of their natural time in summer.

11. After the second world war, certain west European countries (in the GMT zone) gave up the six-monthly changing of the clocks but adopted Central European Time (GMT + 1) as their standard time.

12. Following the oil crisis of the Seventies, the idea of using summer time to save energy was reintroduced in France1 and gradually spread to all European countries.

13. To avoid confusion surrounding the changing of the clocks to summer time and back to winter time, the member states of the EEC in 1980 asked the European Commission to harmonise the dates of the time changes throughout the Community2. Other European countries have adopted the same dates as the Community.

Double summer time

14. The combination of adopting Central European Time while also observing summer time means that five European countries (Belgium, France, Luxembourg, the Netherlands and Spain) are out of step with solar time the whole year round and are over two hours ahead of it in summer (in the westernmost regions). The United Kingdom and Ireland were also in this situation from 1968 to 1971, when they aligned themselves with Central European time, but they abandoned this, as did Portugal in 1996.

15. This situation, which is known as double summer time, produces a number of phenomena that are directly or indirectly harmful to the environment and public health and have implications in other areas, and is unpopular with a fairly large section of the population.

Context of the report

16. It can be assumed that these negative effects also apply, albeit to a lesser extent, in those countries where the simple summer time is adopted. However, as not enough data is available on the matter and the populations of the countries concerned seem to be satisfied with the existing system of summer time, I do not intend proposing that it should be abolished.

17. The report will thus analyse the factors that have negative effects on the environment and human wellbeing and which result from the application of summer time by the five countries whose standard time is not that of their geographical time zone.


18. The various consequences of the application of summer time have been considered in numerous scientific studies3, reports and publications, which this report draws on in substantial measure.

19. I am particularly grateful to the representatives of the various associations4 and to the experts5 who supplied me with the findings of their research and took part in the hearings held in connection with the preparation of this report.

20. I have also consulted the report submitted by the European Commission to the European Parliament and the Council of the European Union with a view to the adoption of the 8th “Summer Time” directive. This report, drafted on the basis of a – hotly contested – study by private consultants, is intended to highlight the advantages of the summer time system, which places great emphasis on econometric calculations to confirm these advantages, notably as regards the economic activities generated by the prolonged light evenings (mainly leisure activities and catering), and tends to dismiss the disadvantages for the environment and health as insignificant.

2.       Consequences of double summer time

21. The combination of non-solar standard time (+ 1 hour) and summer time (+ 1 hour) means that all daytime and night-time activities are two hours ahead of natural time. This results in colder and darker mornings and longer and warmer evenings. At solar midday, the standard time is 2 pm.

Air pollution

Double summer time increases the concentrations of toxic pollutants in the atmosphere.

22. The pollutants present in the atmosphere can be divided into two categories: primary pollutants emitted by sources of pollution (sulphur dioxide, nitrogen oxides, volatile organic compounds, etc) and secondary pollutants formed as a result of the physical and chemical transformation of primary pollutants (sulphuric and nitric acid and their derivatives, photochemical oxidants).

23. Photochemical pollution is a factor that is raising new air pollution concerns. This type of pollution is mainly the result of the action of solar radiation (UV) and high temperatures on nitrogen oxides and hydrocarbons, pollutants which are emitted by human activities (as the combustion products of fossil fuels, in particular those used by motor vehicles) and certain natural sources.

24. It leads to the formation of “photochemical oxidants”. These pollutants include ozone (O3), peroxyacetyl nitrate (PAN), free radicals, formaldehyde (HCHO), nitric acid (HNO3), aerosols, etc.

25. Moving the clocks forward two hours in summer contributes to a build-up of primary pollutants in the atmosphere and causes the period of heaviest traffic in urban areas (2–5 pm) to coincide with that of the highest temperatures and strongest sunshine. This boosts the formation of photochemical oxidants. Various studies conducted in France, Belgium and the United States have shown average increases of between 6% and 10% in ozone concentrations and of between 7% and 16% in PAN concentrations.

26. It should be stressed that these pollutants, in particular ozone and PAN, are known to the medical world for their toxic effects. The main health problems they cause are migraine, respiratory difficulties and irritation of the eyes. The number of deaths related to ozone has been rising for some years6.

27. At the same time, a new phenomenon of die-back in forest ecosystems has been observed in Europe and the United States over the last fifteen years or so. It has been suggested that this is also the result of ozone, which increases cell permeability and thus causes trees to lose nutritive elements through their leaves more easily.

28. It should also be noted that a further effect of higher concentrations of chemically aggressive pollutants (ozone, acids, etc) is the rapid degradation of works of art and historic monuments that are part of humankind’s cultural heritage.

Public health and wellbeing

The difference of two hours (and more in some regions of western France and Spain) between people’s circadian rhythms and the solar cycle causes sleeping difficulties which, in turn, have an impact on general wellbeing, physical equilibrium and intellectual performance.

29. While the existence of a biological clock in mammals was regarded as self-evident, human beings felt until recently that they had freed themselves from nature’s rhythms.

30. Recent research in chronobiology has, however, shown that the human body also has a biological clock that organises the time aspects of our lives. The time and date when most vegetative and hormonal functions occur are not therefore a matter of chance, but are precisely regulated.

31. Our biological clocks are automatically reset by outside synchronisers – primarily the sun – through a complex mechanism in which a key role is played by the pineal gland or epiphysis, which is sensitive to light. In the absence of daylight, it secretes a hormone, melatonin, which is needed for sleep. Secretion stops when daylight returns.

32. The discrepancy between the time people live by and solar time upsets their biological clocks. The effect is most pronounced among children and elderly people, but can also be seen in adults. In the countries with double summer time, people’s organisms are obliged to operate one hour ahead of solar time even in winter. When the clocks are put forward to summer time, this increases to two hours.

33. With the summer time system, the fact that daylight lasts long into the evening means that the secretion of melatonin is delayed and people find it difficult to get to sleep at the normal time, despite being tired from their day’s activities. And the heat, plus the activities they pursue in the long evenings, do not make this any easier.

34. However, in the morning, they have to get up at the time when the concentration of melatonin is at its highest and their sleep is most regenerative, while the length of time they have slept has been reduced either deliberately (to take advantage of the long evenings) or involuntarily (inability to get to sleep). So their bodies are not ready to function "on all 4 cylinders" when they get up.

35. The upsetting of biological rhythms leads to deterioration in people’s general physical wellbeing, as well as to sleeping and memory difficulties, concentration difficulties, asthenia, nervousness and irritability. In the case of children, it harms their performance at school7. For their part, adults suffer from cumulative fatigue. Greater amounts of tranquillisers and sleeping pills are taken.

36. Some studies also refer to even more serious dysfunctions in the human organism, known as “desynchronosis” (loss of appetite, cardiovascular difficulties, etc).

37. The above phenomena occur when the clocks are put forward to summer time and persist in most children and adults for three to four weeks. However, 30% of the population are unable to adapt to summer time at all and suffer the consequences for as long as they are subject to time patterns imposed by society (school, work, etc). Moreover, some body functions go on being geared to solar time and do not adapt at all.

38. In contrast to the above, people have no problems adapting when the clocks are changed back to winter time.

Other consequences:

Energy savings

39. Although energy saving was the reason behind the introduction of summer time, it is no longer the main argument for maintaining the system. The savings achieved (put at 0.5% of annual electricity consumption) have never been convincingly demonstrated in a quantified manner, and their overall impact would appear to be negligible, if not non-existent. Indeed, some studies show that the system can lead to an increase in energy consumption (greater need for heating in the morning, use of air-conditioning, higher fuel consumption because of increased mobility in the evening).

Road safety

40. The overall impact of the summer time system in this area is unclear, as various studies have produced different findings. There would appear to be an increase in the number of road accidents in the morning (morning mist, lack of sleep) and late evening (cumulative fatigue), but a reduction in the late afternoon (improved visibility).

Socio-occupational consequences

41. The summer time system has a negative effect on the working conditions, rest, leisure activities and family lives of farm workers (nature, which sets the rhythm, does not change its clocks, but the families have to live by standard time) and of people who have to start work early in the morning or finish late in the evening.

42. Moreover, people who work in the open air (building sector, etc) start work again after lunch at the very time when the sun is shining most strongly and the temperature is highest.

Leisure activities

43. This sector is often said to benefit most from summer time, as the longer evenings mean that people can engage in outdoor activities (sport, walks, visiting cafés, etc) after work during the week. However, this needs to be put into perspective, as the summer time system works against playing sport in the morning and early afternoon, and also against night-time entertainment events. Moreover, extended activities in the evening add to the general levels of fatigue, as they sometimes replace sleep.

44. It should also be noted that not all the various socio-occupational categories are able to profit from the longer evenings to the same extent. It is mainly urban dwellers working in the tertiary sector who benefit most, while workers in tiring jobs have neither the energy nor the inclination to engage in sport in the evening and also have difficulty in getting to sleep.

45. Although its consequences vary according to several factors (latitude and longitude, time of year, climatic conditions, local traditions, etc), it can be concluded that the overall impact of double summer time is negative both for human beings and for nature.

Public opinion

46. This conclusion is borne out by public opinion in the countries that are two hours ahead of solar time in summer. Opinion surveys have shown that 64% of the French public and 50% of the Belgian public are opposed to the current system. It is in these countries that associations against summer time are very active.

47. The more reserved position of the Spanish people is due to the fact that working hours have been adjusted to reduce the negative effects of summer time.

48. Public opinion in the countries where summer time is only one hour ahead of solar time is somewhat less clear-cut and varies from country to country. People in the Nordic countries greatly appreciate the long summer evenings, which make up for the lack of daylight in winter. In contrast, the Swiss are against the system and have rejected it in a referendum.

Decision-making procedure

49. In most countries, the summer time system was introduced by government regulation. Except in a few cases, the population was not consulted in advance, and indeed does not have any opportunity of democratically expressing its opinion on this system whose pointlessness has become obvious. This undermines the legitimacy of the system, which people see as a technocratic intrusion into private life and an attack on the fundamental parameters of our existence.

Competence for decision-making

50. Through carelessness or because of restricted powers, decision-making on the application of summer time thus escapes the democratic control of parliaments. At the same time, the governments of the member states of the European Union refer to EU directives, which they say they are only applying strictly. Some confusion therefore exists as to the respective powers of the legislative, executive and European authorities in the area of standard time.

51. There can, however, be no doubt that the power to decide on the matter lies with individual states, and the European Union’s only role is to harmonise the dates summer time begins and ends, given that all states have decided to apply it.

52. Moreover, it is the EU transport ministers who are responsible for discussing the “Summer Time” directives and deciding to renew them. Without wishing to deny the importance of these decisions to the transport and communications sector, one might ask whether - given the environmental and health problems caused by the summer time system – that really is the most appropriate forum.

3.       Conclusions and proposals

53. When all the effects of summer time are taken into account, I believe that the best solution would be for all European countries to stop manipulating time zones and revert to the strict application of the Universal Time system both in summer and in winter. This would bring standard time into line with our biological clocks and help reduce pollution.

54. In taking this step, the countries which so wish could adapt working hours in order to derive maximum benefit from daylight.

55. Nevertheless, I realise that not all countries are prepared to take a step of this kind, which cannot be imposed by any outside body and must be the result of careful democratic decision-making.

56. Moreover, the unilateral abandonment of summer time by any one country would damage its trade with its neighbours and would detract from harmonisation and European unity.

57. Yet it would be unfair if the price of harmonisation was to force some nations to live under less favourable conditions than others.

58. I therefore believe that the realistic solution would be for all states to keep to their own geographical time zone in winter and to continue to move the clocks forward one hour in summer.

59. Although this would not completely eliminate the negative effects of the summer time system, it would have the advantage of alleviating their seriousness and bringing human beings closer into line with nature.

60. In practice, it would mean that the countries that currently have double summer time (Belgium, France, Luxembourg, the Netherlands and Spain), those which so wished could revert to the GMT zone to join the United Kingdom, Ireland and Portugal.

61. The original division of Europe into time zones would thus be restored – for the benefit both of humankind and of nature.

62. I should like to point out that states of continental proportions - the USA, Canada, Russia and Australia among others - respect the time zone system without this disturbing either the operation of their economies and their institutions or people's day-to-day lives and relations with the rest of the world.

63. Similarly, the existence in Europe, and in particular in the European Union, of three time zones does not affect trade and cooperation between countries, their institutions and private sector enterprises.


* *

Reporting committee : Committee on the Environment, Regional Planning and Local Authorities

Budgetary implications for the Assembly : none

Reference to committee : Doc. 7757 and Reference No. 2166 of 19 March 1997

Draft recommendation adopted by the committee on 23-24 June 1999

Members of the committee : Mr Akçali (Chairman), MM Besostri (Alternate : Risari), Haraldsson, Hoeffel (Vice-Chairmen), MM. Andreoli, Assis Miranda, Berlusconi, Bockel (Alternate : Dhaille), MM Briane, Browne (Alternate : Gregory), Sir Sydney Chapman, MM Ciobanu, Ciupaila, Cox (Alternate : D. Taylor), Mr Diana, Mrs Dromberg, MM Duivesteijn, Frunda, Mrs Granlund, Mrs Hornikova, MM Kalkan, Kittis, Khukhunaishvili, Kieres, Korakas, Kurucsai, Kurykin, Lachat, Mrs Langthaler, MM Linzer, Luczak, Martinez Casan, Melo, Mezeckis, Mrs Mikaelsson, MM Minkov, Molnar (Alternate : Lotz), MM Mota Amaral, Mozetic, Müller, Mrs Oleinik, MM Prokes, Prosser, Rados, Rakhansky (Alternate : Strizhko), MM Recoder, Rise, Ruffy, Schutz, Mrs Sehnalova, Mrs Severinsen, MM Skoularikis, Sobyanin, Staes, Steolea, Tahiri, Mrs Terpstra, MM Theis, Toshev, Truu, Valkeniers (Alternate : Nothomb), MM Vella, Vishnyakov, Zierer.

NB - The names of those members who took part in the meeting are printed in italics.

Secretaries to the committee : Mrs Cagnolati, Mr Chevtchenko, Mrs Karanjac

1 The United Kingdom and Ireland applied summer time from 1916, Italy did so from 1966 and Greece from 1975.

2 The 8th “Summer Time” directive currently in force covers the period from 1998 to 2001.

3 As regards pollution, these include studies by Dr W Hecq (Free University of Brussels), Prof. H Poppe (Catholic University of Leuven) and Dr JC Déchaux (Lille Science and Technology University), as well as research done in the United States by M Cohen. The functioning of our biological clocks and the effects of summer time on health have been studied by V Mahé and JF Chevalier, G Lac, G Clevidy and A Robert, and Prof. B Sandler.

4 Ms E Gabarain of the French association against double summer time, Ms A Hoff, Mr E Baele, Mr W Deboeverie and Mr G Luyckx of the Belgian association against summer time, and Mr J Denis and Mr L Lebergé of the Association for the return to meridian time.

5 Prof. Besançon, Mr Charbit, Mr Christiansen, Mr Gonnot, Mr Meyer and Prof. Sandler.

6 According to data published by the Ile-de-France Health Observatory, 6% of the deaths, 20% of the hospital admissions of elderly people and 25% of the home visits for respiratory diseases in young children are attributable to ozone and peroxyacetyl nitrate.

7 In 1996, Portugal abandoned double summer time and reverted to UTC in winter and UTC + 1 in summer. The main reason given was the problems schoolchildren had in adapting to double summer time.