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Climate and man
Applied Energy 23 (1986) 189 204
Climate and Man
Neville S. Billington* 4 Clarewood Drive, Camberley, Surrey GUI5 3TE (Great Britain)
SUMMARY The change from a nomadic existence in warm temperate regions to settled communities with a form of government is thought to be due to the need of a n expanding population to colonise marginal areas, and hence to the use of fire for heating, to irrigation and to defence needs. The fall of some ancient civilisations appears to be due to climatic change and to mismanagement of the land. The effect of climate on health and well-being is examined next. Huntingdon and Markham attempted to establish climatic optima; and more recent studies appear to demonstrate that changes in seasonal mortality follow improved indoor temperature control, and perhaps techniques of food preservation. The progress of civilisation and material prosperity seems to depend on fuel supplies. Recent studies have shown that in general a high GNP is associated with high per-capita energy use. A large increase in energy use seems to be necessary in the poorest countries. Finally, the consequences of the increasing use of fossil fuels (atmospheric CO 2 levels, acid rain) are briefly examined.
RISE A N D F A L L O F A N C I E N T C I V I L I S A T I O N S Early in the present century, H u n t i n g d o n 8 sought to find a connection between climate and civilisation. Later, M a r k h a m 9 suggested that civilisation began and developed on the southern shores of the 189 Applied Energy 0306-2619/86/$03.50 ~ Elsevier Applied Science Publishers Ltd, England, 1986. Printed in Great Britain
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Fig. 1.
The Middle East, showing the annual 70°F isotherm and ancient centres of civilisation (after Markham 9).
Mediterranean, the Middle East and the Indus valley, close to the track of the 70 °F annual isotherm,t and thus in areas of the world which enjoyed a 'good' climate, free from the extremes of heat or cold. This was in about 7000 BC (Fig. 1). Markham makes an allowance for sunshine and, by so doing, finds the Mexican climates to be little worse than the Levantine ones. But some other factor must also be at work. Why should 'civilisation' start, and why did many of the ancient civilisations perish? McGhee thought that prolonged drought may have led to the decay of the Mycenean civilisation, and was responsible for the 'dark ages' between 1200 and 750BC, though there was little direct evidence (see Wigley et al. 13). Claiborne 6 attempted to explain both the rise and fall. At the end of the Pleistocene Era (c. 10000BC), man was a hunter and gatherer, and necessarily a nomad, forced to follow the migrations of animals and seasonal changes of vegetation. During the next few millenia, he learned to manipulate animals and plants to a degree which permitted a semisettled life over wide areas, and, in a few places, permanent settlements. t Markham assumed that Bedford's comfort zone would apply also to people living outdoors, and hence that temperatures in the region of 70°F would be necessary in the absence of any heating.
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Burney 5 and Bender 3 describe this process in some detail. The Near East was probably the birthplace of agriculture and pastoralism. Neolithic man in the Near East seems to have achieved a very high degree of control over his environment, to the limit of his economic needs. There was a hesistant, but on the whole a growing, mastery of the natural environment. The Upper Paleolithic groups broadened their diet, and this seems'~to have led to improved !health land lto population growth. (Markham notes, ' H u m a n beings will congregate where natural resources and climate are most favourable. Here they will flourish and multiply until at last the area cannot hold the teeming numbers. Then the adventurous will seek out fresh territories, but, in order to occupy them, must often develop more courage or more cunning than the occupants they wish to displace.') The pressure of population created, as much as resulted from, the conditions favourable to the emergence of permanent villages (before 8000 Bc). There came a time when a proportion of the population abandoned nomadic life and began to build permanent settlements in the open air, normally close to fresh water. Pressure of population, too, from good hunting areas to more marginal ones, is suggested as the stimulus ultimately leading to food production. Wild wheat grew in the upper Tigris valley and in south-east Turkey in more than sufficient quantity to have supported villages: there was thus no stimulus to improve the strains. Such stimulus arose only in marginal areas of perhaps fluctuating rainfall. This change from savagery to barbarism took place in the Middle East, Central America and probably also in China and Peru. 6 The next step to civilisation, marked by fair-sized cities, with specialists such as weavers, potters, merchants, administrators and priests (some of whom were scribes and kept written records) seems to have required special geographic and climatic conditions and occurred in Mesopotamia and Central America. (The other two old civilisations of Egypt and the Indus valley were stimulated from Mesopotamia, though they soon developed distinctive qualities.) Local factors probably account for the appearance of Jericho (c. 8000 BC) and Catal H~yi.ik (Anatolia) (c. 6500 BC), each serving a wide hinterland. Defence became a necessity wherever fertile land and a reliable water supply were available within a restricted area-hence the towers and walls of Jericho. The transition to barbarism arose from the invention of agriculture, for which the climates of the Middle East and the Central American uplands were favourable. Here, quite large climatic differences occur within short
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distances, due to elevations of a few thousand feet. The Mediterranean nomads ofc. 9000 Bc would not need to travel far to follow migrations: it would be relatively easy to carry equipment with them, and there was some incentive to develop more complex tools. Shepherding began (in the Shamidar valley); seeds were planted on the travels for subsequent reaping, laying the foundations of agriculture and animal husbandry and of semi-permanent settlements (c. 7000 Bc) (Claiborne;6 Bender 3). Soon after the beginning of settled life, irrigation was begun, with farreaching social and economic consequences. It required communal organisation, as in Mesopotamia, or by a few families, as in Jericho (Burney 5). About 5500 BC, true civilisation began in the Mesopotamian lowlands, which were well irrigated, opening up large areas of otherwise arid land which was far more productive than the hill country. (Desert soils are among the richest, for there is no leaching, particularly in flood basins.) Villages in hill country had to be abandoned after 200 or 300 years due to soil exhaustion, whereas the valley lands remained fertile for millenia (Claiborne6). There were substantial food surpluses and there was time for leisure. In the 5th millenium BC, there is evidence of trade in ornaments and other artefacts (Bender 3). These islands of wealth were protected against raiding nomads by fortifications. The upkeep of these, and of the irrigation works, called for some sort of organisation--the birth of government. A complex social structure arose--labourers and craftsmen, bureaucrats, intelligentsia, rich and poor. It is time to look at the reasons for decline. Civilisation requires large populations, and hence good and dependable food and water supplies. Early civilisations declined owing to quite small climatic changes, to poor land management and to loss of fertility (Claiborne6). The Tigris Euphrates valley was subject to periodic flooding, though this was less predictable than that of the Nile. It occurred in the spring--an awkward time for crop growing--and this forced river control by dykes, and so on. This circumstance made Mesopotamian civilisation more durable (it lasted 4000 years). Nevertheless, its decline and fall seems to have been inherent in the flood control and river management. Because of the extreme flatness of the valley, the flood waters remained on the land until they soaked away, and this led to salination and loss of fertility, as was noted in Sumerian records of 2400 BC. Silting raised the land level above that of the irrigation canals. The government, too, unsettled by Turkish and Mongol invaders (c. AD 1000), could not cope with the task of building a new irrigation system.
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The Indus valley civilisation arose before 2000Bc and disappeared around 1600 Bc. The climate there is drier than it once was; many of the settlements are remote from modern streams. Overgrazing and forest clearance would destroy a favourable climate and create a dust-bowl, and, eventually, a desert. The civilisation perished as a result of its own success. 'All over the world, expanding populations, along with human thoughtlessness and greed, are engaged in destroying our environment. And once an environment is badly d a m a g e d - - b y man-made desert, by erosion, by pollution--it becomes too much like Humpty-Dumpty on the wall.' (Claiborne 6). The decline of Mycenae (c. 1200 BC) has been attributed by some to climatic change. Claiborne suggests that the Myceneans were an aggressive and predatory people, and to have made and traded in weapons. The final blows were a civil war and uprisings of the peasant militia.
T H E SPREAD OF CIVILISATION Fire was assuredly man's first means of manipulating 'climate', permitting him to colonise cooler areas. It was used by Neanderthal man from c. 35000Bc. Until c. 18000BC, temperatures were still dropping; in 10 000 Bc, glaciers still covered much of north-west Europe. But, by about 7000 BC, ice had disappeared from Britain and most of Scandinavia and by 6400 ac climates were much as they are now. Changes since then have been rather small (a few degrees, a few inches of rain) and of rather short duration (a few centuries). The end of the Ice Age saw changes in the flora and fauna. Game animals were reduced in number: tundra was replaced by forest. Wigley et al.13 suggest ways in which climatic changes may influence the development of cultures, Thus, desiccation, following the northward retreat of the pluvial zone, meant a reduction of the resources available to hunting communities, and hence to the domestication of animals and plants in settled areas. Alternatively, a more humid (and therefore favourable) environment would encourage settlement: the consequent growth of populations led to attempts to increase the food supply by agriculture. Neither hypothesis is proven, nor entirely satisfactory. Another instance is that slight cooling may cause abandonment of marginal areas at high level, and this could become permanent, with the abandonment of the settlements.
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Fire was used by early man for cooking and for making pottery. Kitchen hearths have been discovered at Catal HiJyiik and at Tell Hassuna (Mesopotamia) (c. 5500 Bc), while, in Turkmenia, open-plan houses of the same period with a hearth and raised platform on opposite sides of the room remind one of the kang, used by the Chinese for warming. Metal working by the Sumerians must also have required the use of fire. Agriculture reached Europe via Asia Minor and Greece c. 6000 ac. It took until c. 5000 Bc to reach the Danube valley. Cut-and-burn clearing of the forests enabled the Danubian peoples to undertake agriculture, with, as elsewhere, an increase in population which could expand into an 'almost empty' Europe. Agriculture was brought to Britain c. 3000 Bc. (A rain forest clearing will yield only one or two crops, after which it must be left fallow for 15-20 years, due to leaching of nutrients by heavy tropical rains. On the other hand, a temperate forest clearning will yield for at least twice as long, and will recover in one-third of the time.) Around 1000 Bc, the climate of Europe became cooler and wetter. In Greece, this made it rather better for cropping and, in 700 Bc, Greek civilisation re-emerged, with the devising of a means of combatting cold, superior to the open hearth or brazier. It is thought that the Greeks invented a kind of hypocaust at this time. The leadership of civilisation left the region of the 70°F isotherm and passed to Greece. Intensive agriculture severely damaged the land--a process described by Plato c. 400 Be--leading to soil erosion, river run-off and failing water supplies. But now, instead of declining, Greek farmers turned to olives and vines, which were suited to drier lands. Rome overtook Greece, partly on account of sheer numbers, and partly because the hypocaust was developed much further, making colonisation of cooler lands possible. It declined in the 4th and 5th centuries AD, owing to the combined effects of loss of soil fertility, disunity in the Italian peninsula and invasion by barbarians. The loss of Roman technology pushed Europe back into the Dark Ages (AD500-1300), and power returned to the warmer countries around the 70 ° F isotherm (Markham9). Islamic civilisation was established after the birth of Mahomet (AD 569), the religion serving as a unifying force. In AO 750-800, Baghdad was the world centre of learning. The Moors extended their influence into Iberia (AD 711), and remained dominant until the 1lth century. 'Spain and France developed the richer but barbaric, Celtic cultures, but north Europeans remained impoverished. And even Western Europe
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probably lacked the resources, as it certainly lacked the desire, to advance into full civilisation. It is an ironic fact that the region which was eventually to thrust its own civilisation down the throats of so many "inferior" races was itself initially civilised by the Romans. Northern Europe remained barbarian until the beginning of the Middle Ages.' (Claiborne 6). It was the Spanish who took European civilisation to the Americas, at the expense of the destruction of the indigenous cultures.
CLIMATE AND HEALTH Ancient philosophers have often postulated a connection between climate or weather and health and activity. Thus, Hippocrates (466-377 Bc) said that the inhabitants of cities with an eastern exposure were healthier and superior in intellect and temper to those of the north. Galen thought there was a bodily and mental difference between peoples of the cold north, the torrid south and the temperate region between. A school of pneumatists flourished in Rome (c. 50 BC-AO 400), which studied the quality of air in some detail. They taught that, because night air was 'cold and thick', it caused rheumatism and fever. The air of towns was warm and thick, leading to obesity and sluggishness. The ill-health associated with marshy ground was known. Galen appreciated the physiological changes produced by exposure to, for example, sunshine. He emphasised that moist heat had different effects from dry heat, and he discussed acclimatisation to new environmental conditions and training to perform new kinds of work (Sargent12). The colonisation of India (inter alia) led to studies of the health of expatriates in tropical climates during the 18th century (Sargent ~2). Thus, J. P. Frank, a German physician (c. 1779), wrote: 'Every publicly employed physician should supply the medical description of his region as accurately as possible, and compare every change in weather, every phenomenon concerning the healthiness of a place, with his site so that the science of the influence of human dwellings and the climate of each country becomes better known.' J. Johnson and J. R. Martin worked in India in the early 19th century and jointly published Influence of Tropical Climates. Some Europeans going to the tropics succumbed to disease or had to return for reasons of health.
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Those who remained 'gradually degenerate'--they were unable to adjust to the climate. A Scot, J. Lind (1768), made the distinction between physiological effects of heat and those of illness, and found a constitutional change resulting from acclimatisation. A report by the Carnegie Corporation (1932) believed that the decline of the whites in South Africa was accompanied in every instance by a lack of heating arrangements, lack of protection against sun and lack of cooling arrangements such as solid buildings (Markham9). * Huntingdon 8 in his book Civilisation and Climate, attempted to explain the rise of western economies. He says: 'Certain direct correlations are made between climate and human efficiency as measured by factory work and the marks of students. The conclusion is reached that there are certain optimum conditions of temperature, humidity and storminess. The geographical distribution of civilisation, or of human progress, is practically identical with the geographical distribution of what is here called "climatic energy".' There appears to be a connecting link; namely, health. A 'good' climate is conducive to good health (low mortality) and hence to human energy. Huntingdon's assessment of 'civilisation' was derived from opinions
Fig. 2. Areas of the world showing highest levels of civilisation (after Huntingdon S). * The emergenceof'poor whites'in the West Indiesand in the southern USA was similarly attributed to the effects of climate.
Climate and man
Fig. 3.
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The world showing the areas of optimum and near-optimum climate (after Huntingdon 8).
gathered from some 50 persons--geographers, historians, travellers-who were supposed to assess 'ideals, inventiveness, stability of government, education and leadership'. Huntingdon ignored the indoor temperature or humidity--but this was in the early years of this century when environmental control was poor and cooling non-existent. He goes on:
'In addition to the many efforts being made to foster progress in the south (of the USA), we should add a most vigorous attempt to discover ways of overcoming the handicap of climate.' Markham followed a similar line, though his work was based on statistics, rather than opinion. It is worth noting, and probably significant in relation to industrialisation and the development of the economy (if not ofcivilisation itself), that there is little difference in the temperatures found to be comfortable by white and coloured peoples. Tolerance to higher temperatures is increased when less clothing is worn. In modern times, the German Weather Service (Medical Meteorological Centre) has attempted to classify weather into biologically favourable and unfavourable groups (WMO14). The favourable weather is described as cool to mild, and dry. Unfavourable weather is warm,
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either humid or very dry, or cold. The favourable types of weather are 'exclusively linked with high-pressure areas or anticyclones'. In them, working efficiency is increased (about 20 per cent above average) and accidents reduced (by 6-15 per cent). One cannot immediately equate the 'favourable' group with Mediterranean climates, but they do not fall within the 'unfavourable' group since they are neither very humid nor very dry. The temperature climates of the western world approximate more to the 'favourable' group, and also to Huntingdon's optimum climate. Sakomoto-Moniyama (1977) 6 has demonstrated that, during the past 100 years, the seasonal pattern of deaths among peoples of the northern hemisphere has changed. Before 1900, the mortality peaks occurred in winter and summer. A winter peak only occurred between 1900 and 1950; but, since 1960, no peak is found. The reason was believed to be improved temperature control--first by heating, and latterly by air conditioning (Sargent12). A further factor has been, no doubt, the spread of food preservation and storage by means of refrigeration.
CLIMATE AND WEALTH Markham's thesis implies that when fuel is readily available for manufacture (metal-working, pottery, etc.), civilisation advances. If a high proportion of the available fuel is needed for cooking, heating water and for keeping warm, the growth of civilisation is retarded (or, equally, its spread to cooler climates is delayed). From this point of view, a prerequisite for advancing civilisation is an adequate supply of not-tooexpensive energy, for industrial purposes. (In the modern world, cost, rather than physical availability, may be a determining factor for some Third World countries.) The early civilisations arose in those areas where little fuel was needed for heating: there was an abundance of wood and dung to meet the needs for cooking and for the making of artefacts. Braudel 4 notes that Islamic civilisations did not progress as rapidly as the 'Western' ones because there was a shortage of wood fuel. Power, too, was an important factor. The water wheel was probably invented in Mesopotamia, and perhaps in China, in c. 100 Bc. But it was in Europe, with its many and constant major rivers, where it was developed as a source of power. By 1066, England had 5000 water-mills, and that in a small and undeveloped country (Claiborne6).
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In the Western world today, about half the total energy used is for industry--the rest is for environmental control (heating, cooling, lighting) and for cooking and hot water supply. A cool climate requires the expenditure of fuel to make it tolerable--an unavoidable overhead. Unless fuel is abundant and cheap, the energy needs of industry cannot be met, and the advance of civilisation (here synonymous with industrial growth) must be delayed. The case is different for much of the so-called Third World, situated in warm areas where little fuel is required for heating. For these, even granted the same level of industrialisation, the energy use per capita (and per unit of GNP) would be less than in the Western world. However, an expenditure of energy for cooling is necessary to alleviate the effects of excessive temperatures. It is perhaps philosophically unsound to equate 'civilisation' with material prosperity. Nevertheless, even early history shows that material prosperity is necessary if the arts of civilisation are to be developed--the prosperity provides the means to achieve an ordered, healthy and safe existence, and the leisure and opportunity for literature, music and painting. It has been pointed out that the per capita use of energy is higher in the developed world--and particularly in the USA than in less developed countries. The supposed consequence is that the energy use in these latter countries must be increased if they are to develop (i.e., to become more industrialised). Fritz (see Parker 1°) notes that: 'a firm relationship between energy (use) and development is supported by a rough comparison between the historical statistics of both industrialised and developing countries. However, detailed analysis reveals that the development is not a direct function of a certain energy input.' Nevertheless, a high G N P per capita helps to create financial resources which contribute to health, education and further (technical) developments. The achievement of a certain G N P is, in general, related to energy consumption, though political and social aims have significant effects. Grahtwohl v has used World Bank statistics to illustrate the dependence of G N P on primary energy use. (Here only 'commercial' energy has been considered: traditional fuels such as wood and dung have been excluded, because no data on these are available.) The resulting plot is shown in Fig. 4. We seek to make a rough correction to the World Bank data to allow for the energy used for environmental control, by
Neville S. Billington
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Fig. 4. Relationship between primary energy consumption per capita and gross national product per capita for different countries 1978. The data are taken from World Development Report 1980, World Bank, Washington, DC, 1980 (after Grahtwohl~).
postulating a 40 per cent reduction of energy use in temperate climates (50 per cent in Russia and Poland) to leave 60 per cent as that part contributing to the GNP. For the warm climates, no such reduction is made. The corrected graph is shown in Fig. 5. For the World Bank data, a straight line may be drawn through the cloud of points, whence: G N P = 1000E ( G N P is in US$ per head per annum; E in tons of coal equivalent per head per annum). The corrected graph yields the correlation: G N P = 1500E 1'18 We notice that, when corrected, the G N P per unit of primary energy is larger and, moreover, the G N P increases faster than the growth of energy consumption. At high per capita energy use, any improvement in
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GN P requires a smaller increase in energy use than it does at low energy demand levels. Paucharil 1 believes that the correlation between per capita energy use and economic well-being is strong enough to show that large increases in energy supply are essential for the growth of the poorest nations. Only when a certain level of consumption of'commerciar energy (and hence of GNP) has been reached do technological changes and other means appear feasible for reducing the dependence of economic growth on energy use (i.e., decreasing dE/d(GNP)) so that the economy is able to afford investment. By the same token, investment in energy saving may well be possible only in the richer (more 'advanced') countries, and this further reduces the dependence of G N P on energy supply. Data for Japan illustrate the extent to which this may be possible--in 1970, the energy use per unit of G N P was taken as 100; by 1980, it had fallen to 77. Brookhaven National Laboratory (Anon. ~) has estimated that an annual per capita energy consumption of I tce is necessary to meet basic human needs, while a usage of only 0.5 tce is a bare subsistence level. In the less-developed countries (excluding OPEC and oil-exporting
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nations), the average is only 0.3 tce/a. (This figure probably excluded fuel wood, so that the actual energy use may approach the subsistence level.) Of the poorest countries, forty, with a population of 160 million, are in Africa; the energy consumption is around 0.15tce/a. All have fuel shortages and are highly dependent on oil imports. Another three (Philippines, Thailand and Morocco) have a larger population, and a significantly greater per capita energy use (0.3 tce/a). The argument ought perhaps to be qualified. First, there may be wasteful uses of energy in profligate states (and the success of energysaving campaigns demonstrates this). Secondly, it takes no account of the diversity of economies--agricultural, industrial, mineral extraction-which may exist, and which inevitably demand differing amounts of energy. In a trading world, it is not necessary for every nation to be selfsupporting in every phase and activity. Paucharil i reports studies which show wide differences in the efficiency of energy use in different developing countries--equal changes of energy do not correspond to equal changes in GNP. Economic and technological progress may (and probably does) permit a country to move from one E - G N P curve to another, with a gradual reduction of dE/d(GNP).
WHAT OF THE FUTURE? Destruction of the environment may follow not only from malpractice in land management, but also from pollution of the atmosphere. Concern has been expressed about the possible destruction of the ozone layer through the use of fluor-hydrocarbons as refrigerants or as propellants for a wide variety of spray products, though this now appears not to be a significant factor. Attention has also been directed at the damage caused by acid rain. Acidic emissions resulting from the combustion of fuels, from vehicle exhausts or acidic products arising from the decay of vegetable matter have all been blamed and controversy rages around this subject. It is no doubt possible, at a cost, to reduce sulphurous emissions from power stations and other large users, though it is less easy to see what can be done about small users, though these, too, contribute to the noxious emissions. An alternative being canvassed is to neutralise the acidity of, for example, lakes by the addition of lime; though this is not a solution to the destruction of forests (occurring in Germany).
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The nitrous oxides (&ter alia) produced by internal combustion engines, amongst others, have been responsible for the Californian smogs, which are due to complex photo-chemical reactions combined with local climatic conditions. Wider application of emission controls on vehicles, and of lead in petrol, should reduce this problem to acceptable proportions. Potentially the most damaging, perhaps even catastrophic, is the effect of enhanced CO 2 levels in the atmosphere. It is suggested that increased CO 2 concentrations will enhance the 'greenhouse' effect, by reducing the rate of loss of heat from earth to space, and so lead to a gradual rise in temperatures everywhere. A sufficient rise, of the order of 5 °C, would lead to substantial melting of polar ice-caps, and a rise in sea level and consequent flooding of many large cities. (A rise of at least half this within a century or so is thought possible by several authors.) There would be changes in climate. There is little disagreement as to the general validity of this prognosis; but there is disagreement as to the probable extent of the rise in CO 2 levels. The r61e of the oceans in mopping up additional CO2 is not fully understood and the future trend of fuel usage is unknown. There is little doubt that atmospheric CO 2 has risen throughout this century, and it seems set to continue to do so as long as fossil fuel consumption increases further. Conservation measures aimed at reducing energy use will certainly postpone the crisis. Proponents of nuclear power on the one hand, and of solar, wind and tidal power on the other, have used this debate to further their ends. The extent to which such substitutions are possible or desirable is problematic. Many writers on energy problems are, however, convinced that fossil-fuel consumption ought to be controlled, its increase restrained and, if possible, reversed. Man might conceivably cope with the marginal effects of a climate change by developing new strains of crops and by the extension of environmental control. He is not quite so dependent on nature as the peoples of the early civilisations; but neither is he totally independent of it. Just as some early civilisations perished because of man's own mismanagement, we should take note of current warnings and avoid a similar fate. REFERENCES 1. Anon. Energy needs in developing countrie& Brookhaven National Laboratory, Upton, NY, 1978.
204 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Neville S. Billington W. H. G. Armytage, A social history of engineering, Faber, 1961. B. Bender, Farming in pre-history, Baker, London, 1975. F. Braudel, Capitalism and material life, 1400-1800, Collins, 1974. C. Burney, From village to empire, Phaidon, 1977. R. Claiborne, Climate, man and history, Angus and Robertson, London, 1973. M. Grahtwohl, Worm energy supply, resources, Oldenbourg, 1982. Ellsworth Huntingdon, Civilisation and climate, Yale UP, 1913 (reprinted 1922). S. F. Markham, Climate and the energy of nations, OUP, 1947. J. D. Parker (Ed.), Energy conservation measures, Proe. Int. Symposium, Kuwait, 1983, Pergamon, 1984. R. Pauchari, Financing the energy needs of developing countries, Annual Reviews of Energy, 1982. F. Sargent (II), Hippocratic heritage, Pergamon, 1982. T. M. Wigley et al. (Eds), Climate and history, Cambridge UP, 1981. WMO, A survey of human biometeorology (F. Sargent, II and S. W. Tromp), Worm Met. Organisation TN65, 1964).
Climate and Man
Neville S. Billington* 4 Clarewood Drive, Camberley, Surrey GUI5 3TE (Great Britain)
SUMMARY The change from a nomadic existence in warm temperate regions to settled communities with a form of government is thought to be due to the need of a n expanding population to colonise marginal areas, and hence to the use of fire for heating, to irrigation and to defence needs. The fall of some ancient civilisations appears to be due to climatic change and to mismanagement of the land. The effect of climate on health and well-being is examined next. Huntingdon and Markham attempted to establish climatic optima; and more recent studies appear to demonstrate that changes in seasonal mortality follow improved indoor temperature control, and perhaps techniques of food preservation. The progress of civilisation and material prosperity seems to depend on fuel supplies. Recent studies have shown that in general a high GNP is associated with high per-capita energy use. A large increase in energy use seems to be necessary in the poorest countries. Finally, the consequences of the increasing use of fossil fuels (atmospheric CO 2 levels, acid rain) are briefly examined.
RISE A N D F A L L O F A N C I E N T C I V I L I S A T I O N S Early in the present century, H u n t i n g d o n 8 sought to find a connection between climate and civilisation. Later, M a r k h a m 9 suggested that civilisation began and developed on the southern shores of the 189 Applied Energy 0306-2619/86/$03.50 ~ Elsevier Applied Science Publishers Ltd, England, 1986. Printed in Great Britain
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Fig. 1.
The Middle East, showing the annual 70°F isotherm and ancient centres of civilisation (after Markham 9).
Mediterranean, the Middle East and the Indus valley, close to the track of the 70 °F annual isotherm,t and thus in areas of the world which enjoyed a 'good' climate, free from the extremes of heat or cold. This was in about 7000 BC (Fig. 1). Markham makes an allowance for sunshine and, by so doing, finds the Mexican climates to be little worse than the Levantine ones. But some other factor must also be at work. Why should 'civilisation' start, and why did many of the ancient civilisations perish? McGhee thought that prolonged drought may have led to the decay of the Mycenean civilisation, and was responsible for the 'dark ages' between 1200 and 750BC, though there was little direct evidence (see Wigley et al. 13). Claiborne 6 attempted to explain both the rise and fall. At the end of the Pleistocene Era (c. 10000BC), man was a hunter and gatherer, and necessarily a nomad, forced to follow the migrations of animals and seasonal changes of vegetation. During the next few millenia, he learned to manipulate animals and plants to a degree which permitted a semisettled life over wide areas, and, in a few places, permanent settlements. t Markham assumed that Bedford's comfort zone would apply also to people living outdoors, and hence that temperatures in the region of 70°F would be necessary in the absence of any heating.
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Burney 5 and Bender 3 describe this process in some detail. The Near East was probably the birthplace of agriculture and pastoralism. Neolithic man in the Near East seems to have achieved a very high degree of control over his environment, to the limit of his economic needs. There was a hesistant, but on the whole a growing, mastery of the natural environment. The Upper Paleolithic groups broadened their diet, and this seems'~to have led to improved !health land lto population growth. (Markham notes, ' H u m a n beings will congregate where natural resources and climate are most favourable. Here they will flourish and multiply until at last the area cannot hold the teeming numbers. Then the adventurous will seek out fresh territories, but, in order to occupy them, must often develop more courage or more cunning than the occupants they wish to displace.') The pressure of population created, as much as resulted from, the conditions favourable to the emergence of permanent villages (before 8000 Bc). There came a time when a proportion of the population abandoned nomadic life and began to build permanent settlements in the open air, normally close to fresh water. Pressure of population, too, from good hunting areas to more marginal ones, is suggested as the stimulus ultimately leading to food production. Wild wheat grew in the upper Tigris valley and in south-east Turkey in more than sufficient quantity to have supported villages: there was thus no stimulus to improve the strains. Such stimulus arose only in marginal areas of perhaps fluctuating rainfall. This change from savagery to barbarism took place in the Middle East, Central America and probably also in China and Peru. 6 The next step to civilisation, marked by fair-sized cities, with specialists such as weavers, potters, merchants, administrators and priests (some of whom were scribes and kept written records) seems to have required special geographic and climatic conditions and occurred in Mesopotamia and Central America. (The other two old civilisations of Egypt and the Indus valley were stimulated from Mesopotamia, though they soon developed distinctive qualities.) Local factors probably account for the appearance of Jericho (c. 8000 BC) and Catal H~yi.ik (Anatolia) (c. 6500 BC), each serving a wide hinterland. Defence became a necessity wherever fertile land and a reliable water supply were available within a restricted area-hence the towers and walls of Jericho. The transition to barbarism arose from the invention of agriculture, for which the climates of the Middle East and the Central American uplands were favourable. Here, quite large climatic differences occur within short
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distances, due to elevations of a few thousand feet. The Mediterranean nomads ofc. 9000 Bc would not need to travel far to follow migrations: it would be relatively easy to carry equipment with them, and there was some incentive to develop more complex tools. Shepherding began (in the Shamidar valley); seeds were planted on the travels for subsequent reaping, laying the foundations of agriculture and animal husbandry and of semi-permanent settlements (c. 7000 Bc) (Claiborne;6 Bender 3). Soon after the beginning of settled life, irrigation was begun, with farreaching social and economic consequences. It required communal organisation, as in Mesopotamia, or by a few families, as in Jericho (Burney 5). About 5500 BC, true civilisation began in the Mesopotamian lowlands, which were well irrigated, opening up large areas of otherwise arid land which was far more productive than the hill country. (Desert soils are among the richest, for there is no leaching, particularly in flood basins.) Villages in hill country had to be abandoned after 200 or 300 years due to soil exhaustion, whereas the valley lands remained fertile for millenia (Claiborne6). There were substantial food surpluses and there was time for leisure. In the 5th millenium BC, there is evidence of trade in ornaments and other artefacts (Bender 3). These islands of wealth were protected against raiding nomads by fortifications. The upkeep of these, and of the irrigation works, called for some sort of organisation--the birth of government. A complex social structure arose--labourers and craftsmen, bureaucrats, intelligentsia, rich and poor. It is time to look at the reasons for decline. Civilisation requires large populations, and hence good and dependable food and water supplies. Early civilisations declined owing to quite small climatic changes, to poor land management and to loss of fertility (Claiborne6). The Tigris Euphrates valley was subject to periodic flooding, though this was less predictable than that of the Nile. It occurred in the spring--an awkward time for crop growing--and this forced river control by dykes, and so on. This circumstance made Mesopotamian civilisation more durable (it lasted 4000 years). Nevertheless, its decline and fall seems to have been inherent in the flood control and river management. Because of the extreme flatness of the valley, the flood waters remained on the land until they soaked away, and this led to salination and loss of fertility, as was noted in Sumerian records of 2400 BC. Silting raised the land level above that of the irrigation canals. The government, too, unsettled by Turkish and Mongol invaders (c. AD 1000), could not cope with the task of building a new irrigation system.
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The Indus valley civilisation arose before 2000Bc and disappeared around 1600 Bc. The climate there is drier than it once was; many of the settlements are remote from modern streams. Overgrazing and forest clearance would destroy a favourable climate and create a dust-bowl, and, eventually, a desert. The civilisation perished as a result of its own success. 'All over the world, expanding populations, along with human thoughtlessness and greed, are engaged in destroying our environment. And once an environment is badly d a m a g e d - - b y man-made desert, by erosion, by pollution--it becomes too much like Humpty-Dumpty on the wall.' (Claiborne 6). The decline of Mycenae (c. 1200 BC) has been attributed by some to climatic change. Claiborne suggests that the Myceneans were an aggressive and predatory people, and to have made and traded in weapons. The final blows were a civil war and uprisings of the peasant militia.
T H E SPREAD OF CIVILISATION Fire was assuredly man's first means of manipulating 'climate', permitting him to colonise cooler areas. It was used by Neanderthal man from c. 35000Bc. Until c. 18000BC, temperatures were still dropping; in 10 000 Bc, glaciers still covered much of north-west Europe. But, by about 7000 BC, ice had disappeared from Britain and most of Scandinavia and by 6400 ac climates were much as they are now. Changes since then have been rather small (a few degrees, a few inches of rain) and of rather short duration (a few centuries). The end of the Ice Age saw changes in the flora and fauna. Game animals were reduced in number: tundra was replaced by forest. Wigley et al.13 suggest ways in which climatic changes may influence the development of cultures, Thus, desiccation, following the northward retreat of the pluvial zone, meant a reduction of the resources available to hunting communities, and hence to the domestication of animals and plants in settled areas. Alternatively, a more humid (and therefore favourable) environment would encourage settlement: the consequent growth of populations led to attempts to increase the food supply by agriculture. Neither hypothesis is proven, nor entirely satisfactory. Another instance is that slight cooling may cause abandonment of marginal areas at high level, and this could become permanent, with the abandonment of the settlements.
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Fire was used by early man for cooking and for making pottery. Kitchen hearths have been discovered at Catal HiJyiik and at Tell Hassuna (Mesopotamia) (c. 5500 Bc), while, in Turkmenia, open-plan houses of the same period with a hearth and raised platform on opposite sides of the room remind one of the kang, used by the Chinese for warming. Metal working by the Sumerians must also have required the use of fire. Agriculture reached Europe via Asia Minor and Greece c. 6000 ac. It took until c. 5000 Bc to reach the Danube valley. Cut-and-burn clearing of the forests enabled the Danubian peoples to undertake agriculture, with, as elsewhere, an increase in population which could expand into an 'almost empty' Europe. Agriculture was brought to Britain c. 3000 Bc. (A rain forest clearing will yield only one or two crops, after which it must be left fallow for 15-20 years, due to leaching of nutrients by heavy tropical rains. On the other hand, a temperate forest clearning will yield for at least twice as long, and will recover in one-third of the time.) Around 1000 Bc, the climate of Europe became cooler and wetter. In Greece, this made it rather better for cropping and, in 700 Bc, Greek civilisation re-emerged, with the devising of a means of combatting cold, superior to the open hearth or brazier. It is thought that the Greeks invented a kind of hypocaust at this time. The leadership of civilisation left the region of the 70°F isotherm and passed to Greece. Intensive agriculture severely damaged the land--a process described by Plato c. 400 Be--leading to soil erosion, river run-off and failing water supplies. But now, instead of declining, Greek farmers turned to olives and vines, which were suited to drier lands. Rome overtook Greece, partly on account of sheer numbers, and partly because the hypocaust was developed much further, making colonisation of cooler lands possible. It declined in the 4th and 5th centuries AD, owing to the combined effects of loss of soil fertility, disunity in the Italian peninsula and invasion by barbarians. The loss of Roman technology pushed Europe back into the Dark Ages (AD500-1300), and power returned to the warmer countries around the 70 ° F isotherm (Markham9). Islamic civilisation was established after the birth of Mahomet (AD 569), the religion serving as a unifying force. In AO 750-800, Baghdad was the world centre of learning. The Moors extended their influence into Iberia (AD 711), and remained dominant until the 1lth century. 'Spain and France developed the richer but barbaric, Celtic cultures, but north Europeans remained impoverished. And even Western Europe
Climate and man
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probably lacked the resources, as it certainly lacked the desire, to advance into full civilisation. It is an ironic fact that the region which was eventually to thrust its own civilisation down the throats of so many "inferior" races was itself initially civilised by the Romans. Northern Europe remained barbarian until the beginning of the Middle Ages.' (Claiborne 6). It was the Spanish who took European civilisation to the Americas, at the expense of the destruction of the indigenous cultures.
CLIMATE AND HEALTH Ancient philosophers have often postulated a connection between climate or weather and health and activity. Thus, Hippocrates (466-377 Bc) said that the inhabitants of cities with an eastern exposure were healthier and superior in intellect and temper to those of the north. Galen thought there was a bodily and mental difference between peoples of the cold north, the torrid south and the temperate region between. A school of pneumatists flourished in Rome (c. 50 BC-AO 400), which studied the quality of air in some detail. They taught that, because night air was 'cold and thick', it caused rheumatism and fever. The air of towns was warm and thick, leading to obesity and sluggishness. The ill-health associated with marshy ground was known. Galen appreciated the physiological changes produced by exposure to, for example, sunshine. He emphasised that moist heat had different effects from dry heat, and he discussed acclimatisation to new environmental conditions and training to perform new kinds of work (Sargent12). The colonisation of India (inter alia) led to studies of the health of expatriates in tropical climates during the 18th century (Sargent ~2). Thus, J. P. Frank, a German physician (c. 1779), wrote: 'Every publicly employed physician should supply the medical description of his region as accurately as possible, and compare every change in weather, every phenomenon concerning the healthiness of a place, with his site so that the science of the influence of human dwellings and the climate of each country becomes better known.' J. Johnson and J. R. Martin worked in India in the early 19th century and jointly published Influence of Tropical Climates. Some Europeans going to the tropics succumbed to disease or had to return for reasons of health.
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Those who remained 'gradually degenerate'--they were unable to adjust to the climate. A Scot, J. Lind (1768), made the distinction between physiological effects of heat and those of illness, and found a constitutional change resulting from acclimatisation. A report by the Carnegie Corporation (1932) believed that the decline of the whites in South Africa was accompanied in every instance by a lack of heating arrangements, lack of protection against sun and lack of cooling arrangements such as solid buildings (Markham9). * Huntingdon 8 in his book Civilisation and Climate, attempted to explain the rise of western economies. He says: 'Certain direct correlations are made between climate and human efficiency as measured by factory work and the marks of students. The conclusion is reached that there are certain optimum conditions of temperature, humidity and storminess. The geographical distribution of civilisation, or of human progress, is practically identical with the geographical distribution of what is here called "climatic energy".' There appears to be a connecting link; namely, health. A 'good' climate is conducive to good health (low mortality) and hence to human energy. Huntingdon's assessment of 'civilisation' was derived from opinions
Fig. 2. Areas of the world showing highest levels of civilisation (after Huntingdon S). * The emergenceof'poor whites'in the West Indiesand in the southern USA was similarly attributed to the effects of climate.
Climate and man
Fig. 3.
197
The world showing the areas of optimum and near-optimum climate (after Huntingdon 8).
gathered from some 50 persons--geographers, historians, travellers-who were supposed to assess 'ideals, inventiveness, stability of government, education and leadership'. Huntingdon ignored the indoor temperature or humidity--but this was in the early years of this century when environmental control was poor and cooling non-existent. He goes on:
'In addition to the many efforts being made to foster progress in the south (of the USA), we should add a most vigorous attempt to discover ways of overcoming the handicap of climate.' Markham followed a similar line, though his work was based on statistics, rather than opinion. It is worth noting, and probably significant in relation to industrialisation and the development of the economy (if not ofcivilisation itself), that there is little difference in the temperatures found to be comfortable by white and coloured peoples. Tolerance to higher temperatures is increased when less clothing is worn. In modern times, the German Weather Service (Medical Meteorological Centre) has attempted to classify weather into biologically favourable and unfavourable groups (WMO14). The favourable weather is described as cool to mild, and dry. Unfavourable weather is warm,
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either humid or very dry, or cold. The favourable types of weather are 'exclusively linked with high-pressure areas or anticyclones'. In them, working efficiency is increased (about 20 per cent above average) and accidents reduced (by 6-15 per cent). One cannot immediately equate the 'favourable' group with Mediterranean climates, but they do not fall within the 'unfavourable' group since they are neither very humid nor very dry. The temperature climates of the western world approximate more to the 'favourable' group, and also to Huntingdon's optimum climate. Sakomoto-Moniyama (1977) 6 has demonstrated that, during the past 100 years, the seasonal pattern of deaths among peoples of the northern hemisphere has changed. Before 1900, the mortality peaks occurred in winter and summer. A winter peak only occurred between 1900 and 1950; but, since 1960, no peak is found. The reason was believed to be improved temperature control--first by heating, and latterly by air conditioning (Sargent12). A further factor has been, no doubt, the spread of food preservation and storage by means of refrigeration.
CLIMATE AND WEALTH Markham's thesis implies that when fuel is readily available for manufacture (metal-working, pottery, etc.), civilisation advances. If a high proportion of the available fuel is needed for cooking, heating water and for keeping warm, the growth of civilisation is retarded (or, equally, its spread to cooler climates is delayed). From this point of view, a prerequisite for advancing civilisation is an adequate supply of not-tooexpensive energy, for industrial purposes. (In the modern world, cost, rather than physical availability, may be a determining factor for some Third World countries.) The early civilisations arose in those areas where little fuel was needed for heating: there was an abundance of wood and dung to meet the needs for cooking and for the making of artefacts. Braudel 4 notes that Islamic civilisations did not progress as rapidly as the 'Western' ones because there was a shortage of wood fuel. Power, too, was an important factor. The water wheel was probably invented in Mesopotamia, and perhaps in China, in c. 100 Bc. But it was in Europe, with its many and constant major rivers, where it was developed as a source of power. By 1066, England had 5000 water-mills, and that in a small and undeveloped country (Claiborne6).
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In the Western world today, about half the total energy used is for industry--the rest is for environmental control (heating, cooling, lighting) and for cooking and hot water supply. A cool climate requires the expenditure of fuel to make it tolerable--an unavoidable overhead. Unless fuel is abundant and cheap, the energy needs of industry cannot be met, and the advance of civilisation (here synonymous with industrial growth) must be delayed. The case is different for much of the so-called Third World, situated in warm areas where little fuel is required for heating. For these, even granted the same level of industrialisation, the energy use per capita (and per unit of GNP) would be less than in the Western world. However, an expenditure of energy for cooling is necessary to alleviate the effects of excessive temperatures. It is perhaps philosophically unsound to equate 'civilisation' with material prosperity. Nevertheless, even early history shows that material prosperity is necessary if the arts of civilisation are to be developed--the prosperity provides the means to achieve an ordered, healthy and safe existence, and the leisure and opportunity for literature, music and painting. It has been pointed out that the per capita use of energy is higher in the developed world--and particularly in the USA than in less developed countries. The supposed consequence is that the energy use in these latter countries must be increased if they are to develop (i.e., to become more industrialised). Fritz (see Parker 1°) notes that: 'a firm relationship between energy (use) and development is supported by a rough comparison between the historical statistics of both industrialised and developing countries. However, detailed analysis reveals that the development is not a direct function of a certain energy input.' Nevertheless, a high G N P per capita helps to create financial resources which contribute to health, education and further (technical) developments. The achievement of a certain G N P is, in general, related to energy consumption, though political and social aims have significant effects. Grahtwohl v has used World Bank statistics to illustrate the dependence of G N P on primary energy use. (Here only 'commercial' energy has been considered: traditional fuels such as wood and dung have been excluded, because no data on these are available.) The resulting plot is shown in Fig. 4. We seek to make a rough correction to the World Bank data to allow for the energy used for environmental control, by
Neville S. Billington
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Fig. 4. Relationship between primary energy consumption per capita and gross national product per capita for different countries 1978. The data are taken from World Development Report 1980, World Bank, Washington, DC, 1980 (after Grahtwohl~).
postulating a 40 per cent reduction of energy use in temperate climates (50 per cent in Russia and Poland) to leave 60 per cent as that part contributing to the GNP. For the warm climates, no such reduction is made. The corrected graph is shown in Fig. 5. For the World Bank data, a straight line may be drawn through the cloud of points, whence: G N P = 1000E ( G N P is in US$ per head per annum; E in tons of coal equivalent per head per annum). The corrected graph yields the correlation: G N P = 1500E 1'18 We notice that, when corrected, the G N P per unit of primary energy is larger and, moreover, the G N P increases faster than the growth of energy consumption. At high per capita energy use, any improvement in
201
Climate and man
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GN P requires a smaller increase in energy use than it does at low energy demand levels. Paucharil 1 believes that the correlation between per capita energy use and economic well-being is strong enough to show that large increases in energy supply are essential for the growth of the poorest nations. Only when a certain level of consumption of'commerciar energy (and hence of GNP) has been reached do technological changes and other means appear feasible for reducing the dependence of economic growth on energy use (i.e., decreasing dE/d(GNP)) so that the economy is able to afford investment. By the same token, investment in energy saving may well be possible only in the richer (more 'advanced') countries, and this further reduces the dependence of G N P on energy supply. Data for Japan illustrate the extent to which this may be possible--in 1970, the energy use per unit of G N P was taken as 100; by 1980, it had fallen to 77. Brookhaven National Laboratory (Anon. ~) has estimated that an annual per capita energy consumption of I tce is necessary to meet basic human needs, while a usage of only 0.5 tce is a bare subsistence level. In the less-developed countries (excluding OPEC and oil-exporting
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nations), the average is only 0.3 tce/a. (This figure probably excluded fuel wood, so that the actual energy use may approach the subsistence level.) Of the poorest countries, forty, with a population of 160 million, are in Africa; the energy consumption is around 0.15tce/a. All have fuel shortages and are highly dependent on oil imports. Another three (Philippines, Thailand and Morocco) have a larger population, and a significantly greater per capita energy use (0.3 tce/a). The argument ought perhaps to be qualified. First, there may be wasteful uses of energy in profligate states (and the success of energysaving campaigns demonstrates this). Secondly, it takes no account of the diversity of economies--agricultural, industrial, mineral extraction-which may exist, and which inevitably demand differing amounts of energy. In a trading world, it is not necessary for every nation to be selfsupporting in every phase and activity. Paucharil i reports studies which show wide differences in the efficiency of energy use in different developing countries--equal changes of energy do not correspond to equal changes in GNP. Economic and technological progress may (and probably does) permit a country to move from one E - G N P curve to another, with a gradual reduction of dE/d(GNP).
WHAT OF THE FUTURE? Destruction of the environment may follow not only from malpractice in land management, but also from pollution of the atmosphere. Concern has been expressed about the possible destruction of the ozone layer through the use of fluor-hydrocarbons as refrigerants or as propellants for a wide variety of spray products, though this now appears not to be a significant factor. Attention has also been directed at the damage caused by acid rain. Acidic emissions resulting from the combustion of fuels, from vehicle exhausts or acidic products arising from the decay of vegetable matter have all been blamed and controversy rages around this subject. It is no doubt possible, at a cost, to reduce sulphurous emissions from power stations and other large users, though it is less easy to see what can be done about small users, though these, too, contribute to the noxious emissions. An alternative being canvassed is to neutralise the acidity of, for example, lakes by the addition of lime; though this is not a solution to the destruction of forests (occurring in Germany).
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The nitrous oxides (&ter alia) produced by internal combustion engines, amongst others, have been responsible for the Californian smogs, which are due to complex photo-chemical reactions combined with local climatic conditions. Wider application of emission controls on vehicles, and of lead in petrol, should reduce this problem to acceptable proportions. Potentially the most damaging, perhaps even catastrophic, is the effect of enhanced CO 2 levels in the atmosphere. It is suggested that increased CO 2 concentrations will enhance the 'greenhouse' effect, by reducing the rate of loss of heat from earth to space, and so lead to a gradual rise in temperatures everywhere. A sufficient rise, of the order of 5 °C, would lead to substantial melting of polar ice-caps, and a rise in sea level and consequent flooding of many large cities. (A rise of at least half this within a century or so is thought possible by several authors.) There would be changes in climate. There is little disagreement as to the general validity of this prognosis; but there is disagreement as to the probable extent of the rise in CO 2 levels. The r61e of the oceans in mopping up additional CO2 is not fully understood and the future trend of fuel usage is unknown. There is little doubt that atmospheric CO 2 has risen throughout this century, and it seems set to continue to do so as long as fossil fuel consumption increases further. Conservation measures aimed at reducing energy use will certainly postpone the crisis. Proponents of nuclear power on the one hand, and of solar, wind and tidal power on the other, have used this debate to further their ends. The extent to which such substitutions are possible or desirable is problematic. Many writers on energy problems are, however, convinced that fossil-fuel consumption ought to be controlled, its increase restrained and, if possible, reversed. Man might conceivably cope with the marginal effects of a climate change by developing new strains of crops and by the extension of environmental control. He is not quite so dependent on nature as the peoples of the early civilisations; but neither is he totally independent of it. Just as some early civilisations perished because of man's own mismanagement, we should take note of current warnings and avoid a similar fate. REFERENCES 1. Anon. Energy needs in developing countrie& Brookhaven National Laboratory, Upton, NY, 1978.
204 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Neville S. Billington W. H. G. Armytage, A social history of engineering, Faber, 1961. B. Bender, Farming in pre-history, Baker, London, 1975. F. Braudel, Capitalism and material life, 1400-1800, Collins, 1974. C. Burney, From village to empire, Phaidon, 1977. R. Claiborne, Climate, man and history, Angus and Robertson, London, 1973. M. Grahtwohl, Worm energy supply, resources, Oldenbourg, 1982. Ellsworth Huntingdon, Civilisation and climate, Yale UP, 1913 (reprinted 1922). S. F. Markham, Climate and the energy of nations, OUP, 1947. J. D. Parker (Ed.), Energy conservation measures, Proe. Int. Symposium, Kuwait, 1983, Pergamon, 1984. R. Pauchari, Financing the energy needs of developing countries, Annual Reviews of Energy, 1982. F. Sargent (II), Hippocratic heritage, Pergamon, 1982. T. M. Wigley et al. (Eds), Climate and history, Cambridge UP, 1981. WMO, A survey of human biometeorology (F. Sargent, II and S. W. Tromp), Worm Met. Organisation TN65, 1964).