Changing Climate and Human Response: the Impact of Recent Events on

Climatology

F. KENNETH HARE,* Toronto, Canada

Abstract: Over the last decade climate has become an increasingly significant factor in world affairs because of its effect on food supplies, energy consumption and environmental quality. At the same time the scientific community has had to re-appraise the nature and scope of climatology, increasing political relevance, leading to a growth in interdisciplinary activity involving both naturat and social scientists. The 1980s promise to continue this broadening of scope as the two-way interaction of human societies and the atmospheric system are further explored and evaluated. This paper examines these trends, paying particular reference to the main climate-based environmental concerns currently being debated: the effect of halocarbons on the ozone shield, climate and food production, desertification, the CO; ‘greenhouse’ effect, acid rain and the significance of teleconnections.

introduction

In the 1970s climate became a widely discussed factor in world affairs, chiefly because of its effect on food, energy and environmenta quality. In the same decade the scientific community had to reappraise the nature and value of climatology as a discipline. From being an obscure byway, the study of climate became a popular highway. Moreover, it was seen, by the end of the decade, as an interdisci- plinary activity, requiring the work of many scien- tists outside the atmospheric sciences. The 1980s promise to continue the broadening of scope.

Nowhere was this change more apparent than in the national weather services and their internationa1 co-ordinating body, the World Meteological Organization (WMO). In the 1960s the latter’s Global Atmospheric Research Programme (GARP) had taken shape within the physical and mathemat- ical paradigm traditional to meteorology (a word now seen by many as too narrow in connotation). The 1970s witnessed a rapid shift towards a climatic

*Provost, Trinity College, Toronto, Ontario MSS lH8, Canada.

focus. In 1975 WMO published a landmark docu- ment (WMO, 1975) on the physical basis of climate. It proclaimed the centrality of the climatic theme, and gave the latter the breadth that it required. The climatic system was seen as an entire whole, involving interactions between atmosphere, ocean, biota, soils, rocks, ice and human society. WMO’s conversion culminated in the World Climate Con- ference of 1979, in Geneva, which concentrated attention on the finks between society and variable climate.

Out of this conference came a World Climate Programme, with four component programmes dealing with research, data, applications and socio- economic impact. The research programme is focused on the general circulation of the atmos- phere and on the role of the major biogeochemical cycles, particularly that of carbon. The ultimate aim is to comprehend and predict climatic variation. This is a far cry from the attitude, widespread among meteorologists in earlier decades, that climate was an invariant, and that all variability was distributed about stable means. The applications and impact programmes involve social scientists, ecologists, foresters, soil scientists, fisheries biolo- gists and many others - including geographers,

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38-t Geoforum\~olume 15 Number Y19S-i

who have been astonished to find the rest of the world catching up with their own view of climate!

(See, for example, HARE, 196s.)

prominence (e.g. SCHNEIDER and MESIROW, 1976).

This welcome broadening has not yet had the political and academic impact one would look for (FEDOROV. 1979; WHITE, 1979; KELLOGG and SCHWARE. 1981; HARE, 1951). Social scien- tists, in particular, have only recently begun to articulate methodologies to meet the need (WIL- LIAMS, 1975: AUSUBEL and BISWAS, 1980; CHEN et al., 1983), not without some barracking from atmospheric scientists. In the Soviet Union, where Budyko has led for three decades a move- ment in the same direction (e.g. BUDYKO, 1958, 1982), climatic impact and its mitigation are seen as technical problems requiring only technical solu- tions. Even in the West it has been the atmospheric scientists, rather than their social science neigh- bours, who have given this subject its present

In the following pages I shall attempt an overview of environmental and resource problems that have aided the rise of the new climatology (see Table 1). I

shall suggest [as I have elsewhere (HARE, 1981, 1982)] that climatic anomalies or extremes. together with the impact of technology on the atmosphere, have created opportunities for research that have been funded because of their high political visibility.

These successive situations (summarized in Table 1) have forced atmospheric scientists to broaden their perspective (some willingly, some reluctantly).

I shall be speaking from direct personal involve- ment in each problem and not from careful research

into the evolution of interest. I shall treat the prob- lems in approximately the date order in which, I believe, they influenced the research habits of

Table I. Major problems contributing to change in climatological research, with approximate dates

Perceived problem Actual or predicted climatic characteristics Sample sources

Ozone layer depletion, 1971-

World food crisis, 1973-

Desertification, 1972-

Carbon dioxide build-up (since nineteenth century)

Acid deposition, 1970-

El Nhio effects. 1972-

Volcanic dust loading of strato- sphere, 1980-

none observed. Effect postulated from intru- sion (a) of oxides of nitrogen from aircraft ex- hausts; and (b) of halocarbons, into stratosphere

drought and cold affecting crops in many food-producing areas, especially Soviet Union

intense and progressive desiccation of Sahel and other desert margin areas; associated ecological deterioration

none observed, or only small temperature increase over past century. Large increases foreseen for next century

increasingly acid precipitation and enhanced dry deposition of sulphate and nitrates in northern Europe and north-eastern North America

major climatic anomalies in 1972-1973 and again in 1982-1983, associated with El Nirio events and strong southern oscillations

an old hypothesis revived by explosive erup- tions of Mt. St. Helens, El Chichon and Javanese volcanoes. Assumed cooling

Aftermath of nuclear war, 1982- hypothetical cooling of earth due to all-out nuclear war

JOHNSTON, 1971; CRUTZEN, 1970; NATIONAL ACADEMY DF SCIENCES, 1975. 1979, 1983; BISWAS. 1979; COMESA, 1975

Rockefeller Foundation, 1976; SCHNEIDER and MESIROW, 1976; BISWAS and BISWAS, 1979; BROWN and ECKHOLM, 1974; BRYSON, 1974; BRYSON and MURRAY, 1971

GLANTZ, 1977; UN Conference on Desertification Secretariat, 1977; HARE, 1983a; WMO, 1983

CLARK, 1982; NAS, 1983; KELLOGG and SCHWARE, 1981; MANABE and STOUFFER, 1980

Canada-US, 1983; CALVERT, 1983; RODHE and GRANDELL, 1981

CANE, 1983; GILL and RASMUSSON, 1983; GLANTZ and THOMPSON, 1981; BARBER and CHAVEZ. 1983

RAMPINO and SELF, 1984

TURCO et al., 1983; EHRLICH eral.. 1983

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atmospheric scientists. They will illustrate my conviction that disciplines transform themselves most rapidly under external stimulus and criticism.

Has the flood of research revealed any imminent threat to human welfare? The answer has to be qualified. Acid deposition has created unmistakabIe ecological damage in two parts of the industrialized world. Drought has repeatedly upset the food sys- tem and aggravated the already grievous state of the economies of the less-developed countries. All this has arisen because of mankind’s poor adaptation to climatic variability, which is nothing new. But the carbon dioxide effect, now the most talked-about influence, poses the challenge of major climatic change within the next century. It is not clear that the effect poses a threat, because some of the anticipated changes may be beneficial. But the uncertainty adds importance to the search for understanding of the climatic system and to the comprehension of climatic impact on society.

The Perceived Problems

The ozone layer

The ozone layer is in the lower and middle stratos- phere, where incoming solar ultraviolet radiation creates ozone (0,) out of oxygen (O*). The ozone and oxygen absorb the shorter ultraviolet wavelengths, thereby providing sensitive organisms fike man with essential protection. in nature, the ozone so created is dissociated (a) by recombination of O3 and 0; (b) by attack by hydroxyi (HO) rad- icals, derived from upward diffusing water vapour or methane; (c) by oxides of nitrogen, derived from upward-diffusing nitrous oxide (N,O); and (d) by absorption of other wavelengths of solar radiation. Ozone concentrations are highest in the 20-30 km layer, well below the levefs of maximum formation, are greater in spring than at other seasons and are better developed in high latitudes than in the tropics.

The ozone layer is thus a thin admixture (of the order of parts per million by volume) of a strong ultraviolet absorber, Oj, with the ordinary gases of the stratosphere. Its chemistry is dominated by a series of reactions with other very scarce gases, some of which are carried upwards from the earth’s surface. The dominant modulator of O3 is nitrous oxide, an essential by-product of dinitrification in the soil. In other words, the protective layer of

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ozone is to some extent controlled by surface eco- system functions - an excellent illustration of the interdependence of the components of the environ- ment. The atmosphere provides the transport mechanisms connecting the two domains.

Awareness of the ozone ‘problem’ started with the demonstration by CRUTZEN (1970) of the import- ance of nitrogen oxides to the ozone equilibrium. A year later JOHNSTON (1971) suggested that the exhausts of supersonic aircraft flying at high alti- tudes would introduce such oxides directly into the ozone layer. There could be large reductions in ozone concentration, and even larger increases in ultraviolet radiation at ground-level. Increased inci- dence of skin cancer in humans, plus possible dam- age to other organisms, might ensue.

There was immediate reaction to Johnston’s sugges- tion. The U.S. Department of Transportation, with the colfaboration of 20 other countries, launched the Climatic Impact Assessment Program (CIAP), which attempted an overview of the entire problem (CIAP, 1974). The U.K. and France, concerned for the future of Concorde, similarly carried out exhaustive studies (COMESA-COVOS, 1974; COMESA, 197.5). An overview by the U.S. National Academy of Sciences (NAS, 1975) con- firmed that the effect was real, and that it might well create hazards to human health. However, the cancellation of plans to fly jet aircraft at 20 km or above, plus the uneconomic performance of Con- corde, pushed the issue into the background - though not out of the research agenda.

In 1974 MOLINA and ROWLAND (1974) raised another issue. Large volumes of chemically inert chlorofl uorocarbons, used as refrigerants and spray- can propellants, were being released into the atmos- phere. When they diffused into the stratosphere they would be dissociated by ultraviolet radiation, thus releasing chlorine (Cl,). The latter would also reduce ozone concentrations, perhaps catastrophi- cally. Their paper recharged the controversy just as it seemed to be fading out.

Since then there has been a continuing effort (NAS, 1982) to enlarge our knowledge of the complex chemistry of the stratosphere, particularly (a) to establish by modelling techniques the potential impact of anthropogenic substances on ozone concentration; (b) to measure directly the concen- trations, not only of ozone and its attackers, but of various key intermediaries whereby the chemical

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reactions proceed: and (c) to validate the claims that enhanced ultraviolet radiation at ground-level would indeed have effects on human health and crops, animals and natural vegetation.

Since ozone is a significant absorber of solar radi- ation, it is a control of world climate. If mankind does affect its concentration there will be some effect on temperatures, especially in the warm upper stratosphere. and on tropopause levels. This, in turn, must affect tropospheric weather patterns.

The jury is still ‘out’ on many of these possible impacts. There is as yet no observational proof of an actual decrease of ozone concentration (ANGELL and KORSHOVER. 1953). The chief importance of the ozone problem was. regardless of the out- come, to strengthen research into atmospheric trace chemistry and to demonstrate that chemistry could not be left out of a full understanding of climate. By raising the possibility that far-travelled pollutants, such as the chlorofluorocarbons, might raise the incidence of human cancers, it gave high political visibility to atmospheric research. And by linking ozone concentrations to the nitrogen balance of the soil it proved the need for interdisciplinary approaches. The CIAP and COVOS-COMESA studies involved quantitative attempts, moreover, to calculate the economic costs and benefits, and the actual impact on human health. As such they were among the earliest comprehensive moves towards a methodology for climatic ment.

The food und energy problems

Although there was widespread

impact assess-

malnutrition,

especially in the least developed countries, the 1970s began with gluts in grain in the world cereal markets. The major exporting nations for wheat (the U.S. and Canada) had in place production restraints. In 1971-1972 it was the received wisdom that the huge carry-over stocks then in storage could cushion any weather-induced fluctuations of supply. World cereal production had increased con- tinuously for two decades.

In 1972-1973 a series of events, climatic and political, showed this complacency to be an illusion. Severe drought or cold induced major crop failures in many producing areas, most notably the Soviet Union. The latter had launched a new lands programme that had pushed wheat cultivation into drought-prone areas. The Soviet Union was com-

Geoforum/Volumr 15 Number 311981

mitted. moreover, to raising meat consumption, so it entered the international grain trade as an enor- mous buyer - of 2s million tonnes in the first year. Panic buying by others drove prices up three-fold or

more. A huge inflationary surge thus passed into the world economy just as a perceived energy crisis was more than trebling the price of petroleum. In subsequent crop years the re-entry into production of U.S. and Canadian wheatfields rebuilt reserves. and prices fell again to marginal levels. But there were many weather-induced crop failures in the next eight years. especially in the Soviet Union. In

the U.S. great summer heat and drought reduced

corn production in 1980 and 1983 - the latter at a time when again there were government-inspired cutbacks in production.

Several positions seem to be agreed by the agri- cultural economists. One is that there are still large production gains possible in the exporting countries; food shortages arise from the lack of income to buy, not the lack of capacity to produce. A second is that technology and farm-support pro- grammes are well able to carry Western farmers through years of bad weather; and the same will be true of any longer term climatic variation. And the third is that on the world scale climatic variability is unimportant by comparison with socio-economic influences (SWAMINATHAN, 1979). In spite of the dramatic events of the 197Os, expert studies, conferences and symposia on the world food situ- ation give little prominence to the role of climate, sometimes ignoring it altogether (e.g. CROSSON and FREDERICK, 1977).

But the effect of the food situation on the attitude of

atmospheric scientists was striking. A series of studies by Lester Brown and his associates (e.g. BROWN and ECKHOLM, 1974) implied that the world food supply was stretched to its limit. Among

climatologists BRYSON (1974), LAMB (1976) and ROBERTS and LANSFORD (1979) took similar

views. They also argued that impending climatic change (at that time seen as tending towards greater cold and variability) would worsen matters. The book The Genesis Strategy (SCHNEIDER and MESIROW, 1976) was highly critical of the failure of the agricultural economists to attach sufficient importance to climatic factors.

A key role in this debate was played by the Rocke- feller Foundation of New York (led by Elmore Jackson), which was heavily involved in financing the ‘green revolution’ and other technological

GeoforumiVolume 15 Number 3/195-l

approaches to world food production. The foun- dation also financed research by Walter Orr Roberts at the Aspen Institute of Humanistic Studies, which examined the question of climatic variability and the food situation. Rockefeller orga- nized two conferences - in January 1974 (New York) and in June 1975 (Bellagio) - which led to the publication in 1976 of a report called Climatic Change, Food Production and Interstate Conflict, which reached the desk of Henry Kissinger, then the U.S. Secretary of State. Another report from the Charles F. Kettering Foundation, Impuct of Climatic Fluctuation on Major North American Food Crops (KETTERING FOUNDATION, 1976), gave similar prominence to the political and economic importance of climate. With the prompting of Robert M. White, then Administrator of NOAA in Washington, the U.S. Government gave formal support to the widely espoused idea of a UN-sponsored World Climate Conference. The latter was held in Geneva in 1979, with the support of the key UN agencies.

The most important outcome of this controversy was rising professional interest in climatic variability and in possible lasting climatic change. Major impetus was given to the development of general circulation modelling of atmospheric and oceanic circulations. By mid-decade a substantial part of the research capacity of the atmospheric sciences was being devoted to such large-scale modelling. There were influential voices (e.g. MASON, 1976) that gave prestige to ideas that only a few years earlier had seemed ephemeral.

Though the energy crisis itself played a smaller role in creating this consciousness among atmospheric scientists, it had considerable impact on U.S. opinion, and hence on the funding of research. Three very cold winters in the densely populated mid-west and east U.S. showed that transportation and consumption of energy (and especially of natu- ral gas) were prone to climatic disturbance.

I was closely involved in these particular problems, serving as chairman of the two Rockefeller confer- ences, and as consultant to the Secretary-General of the World Meteorological Organization on the planning and execution of the World Climate Con- ference. I also edited the conference background papers (WMO, 1979).

Desertification

At about the same time as the food crisis, there was

also political concern about intense drought in Sahelian Africa, widely reported as having led to many deaths among human populations due to starvation and to the widespread destruction of livestock and losses of soil. The term desertification became current to describe this loss of productive capacity along the desert margin (RAPP, 1974; RAPP et al., 1974). Subsequent investigations have considerably modified these impressions of the mid- seventies. The reports of human casualties seem to have been exaggerated. And the notion that there was a distinct and well-bounded Sahelian drought in the years 1968-1973 was also over-simplified. In fact, over much of arid and semi-arid Africa a desic- cation began in the early 196Os, which has continued to the present time (WMO, 1983; NICHOLSON, 1983).

The tragedy - for such it nevertheless was - in the Sahel led to the perception that deterioration of semi-arid and arid environments was a widespread phenomenon. Rising populations and food require- ments in the Americas, Asia, Africa and Australia were putting heavy economic pressure on vulner- able ecosystems. The latter were well able to absorb prolonged droughts in their natural condition. The use of such environments to support pastoral or arable livelihood systems weakened that natural resilience. If such use were intensified, the destruc- tion of vegetation and soil, plus the salinization of irrigated land, would sharply reduce potential productivity, in both biological and economic terms. Popular commentators echoed STEBBING’s (1935) colourful image of the outward march of the Sahara across previously fertile land.

The UN system responded by holding a political conference in Nairobi in 1977. The UN Conference on Desertification drew up a plan of action to com- bat the problem and created, within the UN Environment Programme structure in Nairobi, a standing secretariat with technical capabilities. The plan of action, and the background papers, owed much to geographers - notably Gilbert F. White, Jack Mabbutt, Robert W. Kates, Douglas Johnson, Andrew Warren and myself. The conference report was published (UN CONFERENCE ON DESERTIFICATION SECRETARIAT, 1977) and stands as a review of fact and opinion as they appeared in 1976-1977. Once again there were important impacts on the atmospheric sciences, with an impetus towards general circulation modelling. It was suggested (OTTERMAN, 1974) that excessive use of the arid lands decreased vegetation cover and

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hence increased reflectivity to incoming solar radi- ation (albedo). CHARNEY (1975) presented an ingenious hypothesis that such albedo increase should tend to increase middle-tropospheric subsi- dence and hence diminish rainfall. The albedo hypothesis has since been tested by several general circulation modelling experiments and been found to be effective. especially if variable soil moisture is included (CHARNEY et al., 1977; WALKER and ROWNTREE, 1977; CUNNINGTON, 1980; SUD and FENNESSY. 1982; see HARE, 1983a, for overview).

The control of desertification has been a field in which Soviet scientists have also contributed notably. They have a long standing tradition of emphasizing surface energy and moisture balances, and of attempting to modify these balances to com- bat deteriorations in land use. Microclimatological research, in striking contrast to the modelling exer- cises of the Western world, is seen as central to such work (e.g. KOVDA, 1980; NECHAEVA, 1981; DENISOFF, 1982).

The continuing drought in many parts of Africa has forced climatologists to re-examine their widely held conviction that all such events are due to vari- ability of the existing climate. The early 1980s have proved exceedingly drought-prone in both hemis- pheres. In the case of Africa, the question is now being asked: are there other feedbacks at work tending towards lasting desiccation? (WMO, 1983.)

The carbon dioxide effect

The willingness to consider possible climatic change induced by the problems summarized above led, in the later 197Os, to a revival of interest in an old hypothesis - that fossil fuel consumption was rais- ing atmospheric carbon dioxide content world-wide, and that this should lead to rising surface tempera- tures in the next century. Because COa is only slightly soluble in water, the atmosphere rapidly mixes added CO2 on a world-wide scale. The car- bon dioxide issue has become the major thrust of research in modern climatology and is so identified in the World Climate Research Programme (being jointly organized by WMO and the International Council of Scientific Unions, ICSU).

Carbon dioxide (CO*) now makes up 343 parts per million by volume (ppmv) of the well-mixed atmos- phere, for a total atmospheric storage of 723 giga- tonnes (Gt) of carbon. The rate of increase is almost

Geoforum/Volume 15 Number 311983

3 Gt, or about 0.4% p.a. At reasonable rates of fossil fuel consumption the concentration may dou- ble in the latter half of the twenty-first century. Doubled CO* concentration may lead to planetary surface temperature increases of 2-3”C, with high- est increases in north polar regions (because of the positive feedback action of receding snow and ice). These effects arise because CO, is a strong absorb- ing gas in part of the spectrum of infrared emission from the Earth’s surface - and because of the supporting effect of the extra water vapour present in a warmer atmosphere.

Here, again, the response of the atmospheric scien- tists has been to undertake major general circu- lation modelling exercises to establish the effect on future climate (e.g. MANABE and STOUFFER, 1980) and to look for ways of identifying the carbon dioxide effect in the midst of the tumultuous vari- ability so typical of climate (e.g. WIGLEY and JONES, 1981; KELLY ef ul., 1982). In addition it has been realized that other infrared absorbers are increasing and may augment any CO1 warming, perhaps to 50-100%. Once again the chemistry of the atmosphere has proved critical to future cli- mate.

By far the most important consequence, however, has been the great broadening of perspective enforced by the nature of the effect. Atmospheric carbon dioxide concentrations and transfers between the atmosphere and the other reservoirs - such as the biota or the oceans - are part of the global carbon cycle. For the first time, atmospheric scientists are deeply involved with ecologists, oceanographers, geochemists and geologists in com- prehensive modelling of a major biogeochemical cycle (BOLIN, 1979, 1981). This attempt necess- arily involves analysis of the gains and losses of stored carbon in the biota (WOODWELL et al., 1983), in ocean waters and in ocean sediments (BAES, 1982). It also involves the geochemist, among other things because of the use of his methods in establishing past COZ levels (e.g. SHACKLETON et al., 1983). Interactions with gla- cial ice, and consequent sea-level changes, bring in the glaciologist and glacial geologist (e.g. HOFF- MAN et al., 1983).

The literature of this effect is already vast. Nevertheless, comprehensive overviews have been attempted (CLARK, 1982; NATIONAL ACADEMY OF SCIENCES, 1983). These over- views illustrate the new broad mode that climatic

Geoforum/%‘olume 15 Number 3/198-r

research is expected to adopt. The breadth arises not only from the interdisciplinary character of the research, but from the scope and scale of potential impact. Carbon dioxide-induced climatic change (and the direct effect of CO? on the biota) clearly touches on energy policy, agriculture, transpor- tation, forestry, fisheries, public health, water supply and many aspects of technology (SEIDEL and KEYES, 1983). I have myself attempted an overview of such impacts in Canada (HARE, 1983b).

In the 1980s several other effects have reinforced the impact on climatology of the foregoing matters. I can review such effects only briefly.

Much attention was given in the 1970s to the grow- ing acidity of precipitation in the north European countries. In fact the 1972 UN Conference on the Human Environment in Stockholm arose in part from Swedish concern over damage to their lakes by sulphate ion deposition derived from industrial Western Europe. Studies sponsored by the Organiz- ation for Economic Cooperation and Development (OECD) confirmed the reality of the effect and stressed the transnational travel of pollutants (sul- phur and nitrogen compounds) as causal factors. In 1979 the UN’s Economic Commission for Europe in Geneva adopted a convention on transnational (transboundary) air pollution. Canada and the U.S., as members of ECE, were signators.

The realization that acidification of surface waters was also under way in North America came onty in the 1970s. After accepting the 1979 Geneva Convention, the U.S. and Canada signed a 1980 Memorandum of Intent to abate mutual problems of transboundary air pollution - in practice mainly sulphates and nitrates contributing to acid depo- sition. As in Europe, no politicat solution has been found to the problem that the culprit emissions occur largely in one country and the damaging depositions in another. Nevertheless, there has been a large body of research conducted by both countries, again as in Europe.

The acid deposition problem has still further streng- thened two vital shifts in emphasis in the atmos- pheric sciences. It has added yet another body of atmospheric chemistry to the literature and another pool of expertise to the roster of available skills. It has again required extensive modelling experi-

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ments, this time devoted to prediction of source- receptor reIationships on sub-continental scales rather than the global scale of general circulation models. It has also revealed the inadequacy of our present understanding of the climatology of mesos- tale circulations (see, inter a&, CANADA-U.S., 1983; CALVERT, 1983; BOLIN and PERSSON, 1975; RODHE and GRANDELL, 1981).

A further recent influence has been a revival of interest in the impact of explosive volcanic erup- tions on atmospheric temperatures. This was a field pioneered by Hubert Lamb and Reid Bryson. It is now usually assumed that tropospheric dust load- ing, such as that resulting from desertification, has only minor climatic effects, but that the volcanic injection of sulphur dioxide into the stratosphere - with the consequent formation of persistent sul- phate aerosol layers - may cool the &mate for up to three years. The 1980s have seen a resumption of expfosive vulcanism, which in the past (e.g. Tam- bora, 1815; Krakatoa, 1883) is known to have pro- duced such toolings. The major stimulus has come, however, from the eruption of El Chichon in Mex- ico in early April 1982, which produced a stratos- pheric aerosol layer larger than any other since Krakatoa (e.g. RAMPINO and SELF, 1984). Analysis of the effects on world temperatures is not yet complete.

Twice in the past 15 years anomalous El Nido events off the Peruvian coast, with the associated atmospheric changes of the Southern Oscillation, have produced major upsets in the world economy. That of 1972 produced the collapse of the Peruvian anchovy fisheries, up until then a prime source of protein in the world’s livestock diets. Coming as it did at the same time as the climax of the Sahelian drought and the 1972-1973 crop failures, this event attracted widespread attention. It initiated exten- sive oceanographic and climatological research [for an overview, see GLANTZ and THOMPSON (1981)].

Far larger and much odder in performance was the great El Nitio of 1982-1983. This event was assoc- iated with widespread climatic anomalies - droughts, floods, heat, cold - over much of the Pacific basin and both North America and Eurasia (QUIROZ, 1983). There were also striking differ- ences in oceanographic events and biological impacts (CANE, 1983; BARBER and CHAVEZ, 1983; FIRING et al., 1983). This event promises to open up a whole new wave of interest in tefeconnec-

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tions (such as the relation of the Southern Oscil- lation to the Indian Monsoon. or to the major climatic anomalies of 19S2-19S3 over North Amer- ica). Again the drive will be towards modelling, especially towards that difficult but desirable goal. fully coupled ocean-atmosphere models (GILL and RASMUSSON, 19S3).

The most recent of the politically visible influences has been concern about the effects of nuclear war on climate, a theme introduced by CRUTZEN and BIRKS (19S2) and most recently by TURCO et (II. (1983) and ERHLICH et al. (1983). Though there have been many past attempts at estimating the deaths. injuries and physical destruction that would follow ail-out nuclear war, the climatic impact has been seriously investigated only in the past three years. A dramatic cooling of climate lasting many months is predicted over much of the world. Smoke from fires and dust from the blast are expected to be responsible. Since temperatures are predicted to fall well below freezing, devastation of tropical and temperate biotas is foreseen. Once again large-scale modelling underlies these analyses - modelling of the chemistry as well as of the climatic impact.

Climatic impact Assessment

The intimate relationship between human affairs and climate is, of course, an old theme for geo- graphers. It played a significant role in the deter- minism of Ellsworth Huntington and Griffith Taylor. And in modern times the adjustment of human behaviour to perceived climatic hazards has been a significant research thrust - for example in the work of Gilbert F. White, Robert W. Kates, Ian Burton and Anne Whyte. The economic adjustment to climate has also received attention, for example in the work of John Maunder and Andris Auliciems.

Nevertheless, the stresses of the 1970s and early 1980s have shown that climatic impact assessment is still a poorly developed art. At the World Climate Conference of 1979 it became apparent that the spokesmen of many economic sectors had simply not asked the question: what is the role in specific industries of climate and its variation? Nor was any organized response visible among the social scien- tists, especially the economists. It became obvious, in fact, that climatic variability was seen simply as a source of random perturbations in the production and consumption of goods. Certainly this was true of the food system. The distinguished spokesman

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for that sector. V.S. Swaminathan, gave little prominence to climate in his address to the confer-

ence (SWAMINATHAN. 1979).

Much human technology is. of course. adaptation to climate. Building and clothing design, farming tech- niques (crops, animals, machinery and the annual cycle of activity) and transportation equipment are all climate-adapted. Not merely are they appropri- ate for mean conditions. but they also implicitly take account of variability. It is only when such variability involves deviations outside expectation that there is perceived to be a climatic impact. Extreme events, that is to say, make the observer conscious of climate as an economic, social and

physiological factor. Adaptation to ordinary climatic variability is largely unconscious.

In the light of the problems reviewed above there have been several attempts to remedy the situation. An early response was to discuss man’s impact on the climate. This continues apace, as each new threat to climatic stability is identified. Much of the discussion of the COz effect has had this direction (e.g. BACH er al., 1979; SEIDEL and KEYES, 1983). But there is a growing literature that looks the other way. The International Institute of Applied Systems Analysis at Laxenburg, Austria, has sponsored several analyses of climate’s impact on mankind (e.g. WILLIAMS, 1978; AUSUBEL and BISWAS, 1980). The National Center for Atmospheric Research at Boulder, CO, has for some years supported a staff of social scientists looking at climatic impact, as has the Aspen Insti- tute for Humanistic Studies (e.g. GLANTZ, 1977; KELLOGG and SCHWARE, 1981). The Amer- ican Association for the Advancement of Science has for some years supported a climate project that has concentrated on the proper approach to impact assessment (see, e.g., SLATER and LEVIN, 1981; CHEN er al., 1983). The last reference, in particu- lar, examines the social disciplines, one by one, to suggest tactics.

The World Climate Programme includes a study of impact analysis, being coordinated by the UN Environment Programme. A team of 26 authors from 16 countries, led by Robert W. Kates, is preparing a SCOPE* report which, they hope, will

*Scientific Committee on Problems of the Environment, a body having its headquarters in Paris. Its parent is the International Council of Scientific Unions, which shares in the direction of the World Climate Programme.

Geoforum/Volume 15 Number 3 1981

be a prescriptive document for the design of climatic impact assessments.

I confess to a little impatience with the spate of methodological writing that the situation has called forth. What the world needs is an actual assessment of what climate has done, and changing climate may do, to the economy and human welfare. The SCOPE report heads in this direction.

Other Sources of Change

The discipline of climatology has not depended wholly on these external stimuli for its evolution. On the contrary, there has been an explosion of activity in fields quite remote from contemporary climatic impact.

Thus the geochemists, marine scientists and others have used the past decade and a half to give us a new, detailed and in some ways revolutionary account of Pleistocene and Holocene climatic vari- ation. The bottom sediments of the ocean and the continental ice sheets have yielded an extraordinary weatth of new knowledge about climatic variation over the past 2 million years, largely through iso- tope analysis. More precise dating techniques have sharpened the focus. And the evidence from these data has allowed the revival of the Milankovitch hypothesis that orbital relations of Earth to Sun can account for much of the observed variability of cli- mate on these time scales (HAYS et al., 1976).

In fact the relevance of palaeoclimatology has now become so obvious that public funding is widespread for what used to be seen as highly esoteric research. The study of past climates, especially if they can be related to external factors such as CO2 concentration and ice volume, is immediately useful in assessing the implications of future climatic change. A new version of uniformitarianism seems to be in the making: that the past is the key to an understanding of the future. Particularly helpful has been the sudden revival of historical climatology (e.g. WIGLEY ef al., 1981; LAMB, 1982). a field in which the Climatic Research Unit of the University of East Angha has played a key role.

Lurking in the background of all this change, however, is a purely technological factor - the increasing sophistication and capacity of computers. Going with this has been the slow amassing of elaborate data sets that can be used in climatolog-

391

ical research. Climatologists sit on vast volumes of recorded observation, but these are largely useless until they are sorted into usable form. The entire research community is in debt to those who have tackled this tedious work. Without the fastest of computers and properly organized data sets, research into the behaviour of present and future climates is limited in scope.

Much the same can be said for the meteorological satellites, though we are as yet a long way from being able to use their output to maximum effec- tiveness, They have produced an explosion of new data that are very hard to absorb.

All of this implies the continuance and growth of the old-established tradition of international co- operation. Climate is a transnational, globa phe- nomenon. All its problems have transboundary implications, and none can be satisfactorily solved on a national basis.

Conclusion

The essential conclusion of this essay is that the study of climate has been greatly expanded and enriched during the past 15 years, to the point where it now appears to be the central objective of the atmospheric sciences. Whether most of those involved would call the new approaches climatology is another matter. Meteoroiogists still cling to the notion of average weather. But the name is unim- portant. What matters is that an adequate percep- tion of the nature of climate has now. at last, arrived.

The second conclusion is that external social and political pressures have had as much or more to do with the changes as has climatology’s own internal evolution (though the latter has been considerable). A succession of urgent probiems has demonstrated the importance of climate in the political domain, and also made essential the interdisciplinary approaches now so visible. Especially effective were the ozone problem, the food crisis and the carbon dioxide issue.

In greater detail I conclude as follows:

(i) Much of the growth in visibility and versatil- ity achieved by the atmospheric sciences since 1970 has been due to the environmental sensitivity of the political system. The ozone

392

(ii)

(iii)

(iv)

(v)

(vi)

(vii)

(viii)

and acid rain issues, in particular, are seen as central to the public objective of protecting environmental quality. Politicians have hence put pressure on atmospheric scientists to lead interdisciplinary searches for solu- tions to the problems,

This environmental thrust has also led natur- ally to the establishment of closer contacts between climatologists, ecologists and the various resource specialists. The notion of the climatic system as the object of enquiry dictates that broadly interdisciplinary approaches dominate future developments in the field.

The notions of climatic system and eco- system are obviously closely related. In par- ticular the biogeochemical cycles, especially those of carbon and nitrogen, are common to both paradigms. Carbon cycle research is already seen as central to the prediction of future climate.

The traditional links between the physical study of the oceans and the atmospheric sci- ences are becoming closer than ever. In par- ticular, recent studies of the El Nirio- Southern Oscillation phenomena, and their teleconnections, demonstrate that there is a need for closer dynamical investigation of air-sea interaction.

Atmospheric chemistry, for long a neglected field, has undergone a remarkable growth. Its study is essential to the analysis and prediction of climate.

The central working method of climatology is the numerical model used on all appropri- ate scales and applied to as many interactions of the climatic system as possible. Computer and satellite support are essential to the sci- ence’s health. So also are international agen- cies and co-operation.

The study of palaeoclimatology, on all time scales, is of direct relevance to the understanding of present day climate and to prediction of the future.

There is a need for much more effective assessment of climate’s impact on society - not only in relation to the solution of prob-

(ix>

Geoforum’Volume 15 Number 311984

lems, but to the contribution of the social sciences.

Applied climatology has taken on new wings. In the fight against desertification, for example, there have been many new appli- cations made effective in the past decade - especially the energy and moisture balance approaches of the Soviet scientists.

It has been an exciting time for climatologists and their brethren. They have been conscious of a major change in the status of their science and of the resources available to it. Yet it should be recalled that the breadth and interdisciplinarity of the modern science were implicit in the thinking of its founders - for example, in the climatic taxonomies epoused by KOPPEN and THORNTHWAITE. There is nothing new under the Sun - but there are new ways of examining what its rays reveal.

References

ANGELL, J. K. and KORSHOVER, J. (1983) Global variation in total ozone and layer-mean ozone: an update through 1981, J. Climate appl. Meteor., 22, 1611-1627.

AUSUBEL, J. and BISWAS, A. K. (Eds.) (1980) Cfima- tic Cor1straint.s and Human Activities, Vol. 10, Pro- ceedings, International Institute for Applied Systems Analysis, Laxenburg. Pergamon Press, Oxford.

BACH, W., PANKRATH, J. and KELLOGG, W. (Eds.) (1979) Man’s Impact on Climate, Developments in Atmospheric Science No. 10. Elsevier, Amsterdam.

BAES, C. F., Jr (1982) Effects of chemistry and biology on atmospheric carbon dioxide, In: Carbon Dioxide Review 1982, pp. 189-204, W. C. Clark (Ed.). Clarendon Press, Oxford.

BARBER, R. T. and CHAVEZ, F. P. (1983) Biological consequences of El Nitio, Science, 222, 1203-1210.

BISWAS, A. K. (Ed.) (1979) The Ozone Layer. Perga- mon Press (for the UN Environment Programme), Oxford.

BISWAS, A. K. and BISWAS, M. R. (1979) Food, Cli- mate and Man. Wiley-Interscience, New York.

BOLIN, B. (1979) Global ecology and man, In: Proceed- ings of the World Climate Conference, pp. 27-49. WMO, Geneva.

BOLIN, B. (Ed.) (1981) Carbon Cycfe Modefling, SCOPE 16. Wiley, Chichester.

BOLIN, B. and PERSSON, C. (1975) Regional disper- sion and deposition of atmospheric pollutants with particular application to sulphur pollution over west- ern Europe, Tellus, 27, 281-309.

BROWN, L. R. with ECKHOLM, E. P. (1974) By Bread Alone. Norton, New York.

GeoforumiVolume 15 Number 31198-t

BRYSON. R. A. (197-t) A perspective on climatic change, Science. 181. 753-760.

BRYSON, R. A. and MURRAY. T. J. (1971) Climarer of Hunger. University of Wisconsin Press, Madison, WI.

BUDYKO, M. I. (1958) T!zhe Heat Balance of the Earrh’s Surface (trans. N.A. Stepanova). U.S. Department of Commerce, W’ashington, DC.

BUDYKO, M. I. (1982) The Enrrh’s Climnte: Past and Future, Vol. 29. International Geophysics Series. Academic Press. New York.

CALVERT, J. (1983) Acid Deposition: Atmospheric Pro- cesses in Eastern North America. National Academv Press, Washington, DC.

CANADA-UNITED STATES MEMORANDUM OF UNDERSTANDING ON TRANSBOUNDARY AIR POLLUTION (1983) Work Groups Reports, 3 vols. Ottawa and Washington, DC.

CANE, M. A. (1983) Oceanographic events during El Nirio. Science, 222, 1189-1202.

CHARNEY, J. (1975) Dynamics of deserts and drought in the Sahel, Q. J. roy meteor. Sot., 101, 193-202.

CHARNEY, J.. QUIRK. W. J., CHOW, S. H. and KORNFIELD, J. (1977) A comparative study of the effects of albedo change on drought in semi-arid regions, J. atmos. Sci., 33, 1366-1385.

CHEN, S., BOULDING. E. and SCHNEIDER, S. H. (Eds.) (1983) Social Science Research and Climnte Change: an interdisciplinary Appraisal. Reidel, Dor- drecht.

CIAP (Climatic Impact Assessment Program) (197-t) Report of findings, In: The Effects of Stratospheric Pollution by Aircraft, A. J. Grobecker, S. C. Coroniti and H. R. Cannon, Jr. National Technical Information Service, Springfield, VA.

CLARK, W. C. (1982) Curbon Dioxide Review 1962. Clarendon Press, Oxford.

COMESA, (1975) Report of the Committee on Meteorological Effects of Stratospheric Aircraft (Chair- man: Murgatroyd, R. J.). Meteorological Office, Bracknell.

COMESA-COVOS (1974) Anglo-French Symposium, Proceedings, September 24-26, 2 ~01s. Meteorological Office, Bracknell.

CROSSON, P. and FREDERICK, K. D. (1977) The World Food Situation. Resources for the Future, Washington, DC.

CRI-JTZEN, P. J. (1970) The influence of nitrogen oxides on the atmospheric ozone content, Q. J. roy. meteor. Sot., 96, 320-325.

CRUTZEN, P. J. and BIRKS, J. W. (1982) The atmos- phere after a nuclear war: twilight at noon, Ambio, 11, 114-125.

CUNNINGTON. W. M. (1980) The sensitivity of the Saharan region in an 11-layer model as indicated by rainfall amounts, WGIVE Reports, 21, 82-83.

DENISOFF, I. A. (1982) Soil Depletion and Degradation Control in the Tropics. Center of International Pro- jects, GKNT, Moscow.

EHRLICH, P. R. ef al. (1983) Long-term biological con- sequences of nuclear war, Science, 222, 1293-1300.

FEDOROV, Ye. K. (1979) Climatic change and human strategy, In: Proceedings of the World Climate Confer- ence, pp. 15-26. WMO. Geneva.

FIRING, E., LUKAS, R., SADLER, J. and WYRTKI,

393

K. (1983) Equatorial undercurrent disappears during 1982-1983 El Nitio. Science, 222, 1121-1123.

GILL, A. E. and RASMUSSON, E. M. (1983) The 1982-1983 climate anomaly in the equatorial Pacific. Nature. 306, 229-234.

GLANTZ, .M. H., (Ed.) (1977) Desertification. Westview Press, Boulder, CO.

GLANTZ, M. H. and THOMPSON. J. D. (1981) Resource Mnnagement and Environmental Uncer- tainty: Lessons from Coastal Upwelling Fisheries. Wiley-Interscience, New York.

HARE, F. K. (1968) New wings for climatology, In: Eclectic Climatology. pp. 145-162, A. Court (Ed.). Oregon State University Press, Corvallis.

HARE, F. K. (1981) Climate: the neglected factor?, Int. J., 36, 371-387.

HARE, F. K. (1982) Climate: yesterday, today and tomorrow, In: The Great Ideas Today, pp. 51-103. Britannica Great Books, Chicago.

HARE, F. K. (1983a) Climate and Desertification: A Revised Analysis, World Climate Programme Report 44. WMO, Geneva.

HARE, F. K. (1983b) Future climate and the Canadian economy. Climatic Change in Canada 3, Syllogeus, 49. 15-49.

HAYS, J. D., IMBRIE, J. and SHACKLETON, N. J. (1976) Variations in the Earth’s orbit: pacemaker of the ice ages, Science, 194, 1121-1132.

HOFFMAN, J. S., KEYES, D. and TITUS, J. G. (1983) Projecting Future Sea Level Rise, 2nd revised Edn. U.S. Environmental Protection Agency,

JOHNSTON, H. S. (1971) Reduction of stratospheric ozone by nitrogen oxide catalysts from supersonic transport exhaust, Science, 173, 517-522.

KELLOGG, W. W. and SCHWARE, R. (1981) Climatic Change and Society: Consequences of Increasing Atmospheric Curbon Dioxide. Westview Press (in co- operation with the Aspen Institute for Humanistic Studies), Boulder, CO.

KELLY, P. M., WIGLEY, T. M. L. and JONES, P. D. (1982) Commentary, In: Carbon Dioxide Review 1982, po~;~~;ldq-251, W. C. Clark (Ed.). Clarendon Press,

KETTERING FOUNDATION (1976) fmpact of Clima- tic Fluctuation on Major North American Food Crops. Kettering Foundation and the Institute of Ecology, Dayton, OH.

KOVDA, V. (1980) Problem of Combating Salinization of frrigated Soils. Center of International Projects, GKNT, Moscow.

LAMB, H. H. (1976) On the frequency and patterns of variation of climate: an opening statement on climate change, In: Climatic Change, Food Production and Interstate Con&t, pp. 40-58. Rockfeller Foundation, New York.

LAMB, H. H. (1982) Climate, History and the Modern World. Methuen, London,

MANABE, S. and STOUFFER, R. J. (1980) Sensitivity of a global climate model to an increase of COz con- centration in the atmosphere, J. geophys. Res., 85, 5529-5554.

MASON, B. J. (1976) Towards an understanding and prediction of climatic variations, Q. J. roy. meteor. Sot., 102, 473-498.

MOLINA, M. J. and ROWLAND, F. S. (1974) Stratos-

394

pheric sink for chlorofluoromethanes - chlorine atom-catalysed destruction of ozone. Suture, 249, 8104312.

NAS (National Academy of Sciences) (1975) Environ- mental Impact of Stratospheric Flight. NAS. Washing- ton. DC.

NAS (1979) Protection Against Depletion of Stratospheric Ozone by Chlorofhcorocarborzs. NAS. Washington, DC.

NAS (1983) Changing Climate, Report of the Carbon Dioxide Assessment Committee. National Academy Press.

NECHAEVA. N. T. (Ed.) (1981) Rangeland Ecology, Management arzd Productiviry, 2 Vols. Center of Inter- national Projects, GKNT, Moscow.

NICHOLSON, S. (1983) Sub-Saharan rainfall in the years 1976-1980: evidence of continued drought. Monthly Weath. Rev., 111, 1646-1654.

OTTERMAN, J. (1974) Baring high-albedo soils by overgrazing: a hypothesized desertification mechan- ism, Science, 186, 531-533.

QUIROZ. R. S. (1983) The climate of the “El Nido” Winter of 1982-83 - a season of extraordinary cli- mate anomalies, Monthly Went/z. Rev., 111, 1685- 1706.

RAMPINO, M. R. and SELF S. (1984) The atmospheric effects of El Chich6n. Scient. Am. 250, 48-57.

RAPP, A. (1971) A Review of Desertification irz Africa - Water, Vegetation, and Man, SIES Report I. Secretar- iat for International Ecology, Stockholm.

RAPP. A., Le HOUEROU, H. N. and LUNDHOLM, B. (1973) Catz Desert Encroachmetzt be Stopped? Ecological Bulletin 24. Swedish National Research Council, Stockholm.

ROBERTS, W. 0. and LANSFORD, H. (1979) Ttze Climute Mandate. Freeman, San Francisco, CA.

ROCKEFELLER FOUNDATION (1976) Clinzatic Change, Food Production and Interstate Conflict, Report of a Bellagio Conference. Rockefeller Foun- dation, New York.

RODHE, H. and GRANDELL, J. (1981) Estimates of characteristic times for precipitation scavenging, J. utn~os. Sci., 38, 370-386.

SCHNEIDER, S. H. and MESIROW, L. (1976) 7Xe Genesis Strategy: Climate and Global Survival. Plenum Press, New York.

SEIDEL, S. and KEYES, D. (1983) Can We Delay a Greenhouse Warming? Environmental Protection Agency, Washington, DC.

SHACKLETON, N. J., HALL, M. A., LINE, J. and CANG SHUXI (1983) Carbon isotope data in core V19-30 confirm reduced carbon dioxide concentration

Geoforum,+‘olume 15 Number 3/1981

in the ice age atmosphere. Suture. 306, 319-322. SLXTER. L. E. and LEVIN. S. K. (19dl) Climate’s

Impact on Food Supplies. AAAS Selected Symposium 61. Westview Press, Boulder. CO.

STEBBING. 0. (1935) The encroaching Sahara: the threat to the IVest African colonies. Geog. Jl, 85, 506-52-I.

SUD. Y. C. and FENNESSY. M. (1982) A study of the influence on surface albedo and July circulation in semi-arid regions using the GLAS GCM. J. Climatol, 2. 105-125.

SWAMINATHAN. V. S. (1979) Global aspects of food production. In: Proceedings of the World Climate Con- ference, pp. 369405. WMO. Geneva.

TURCO, R. P.. TOON, 0. B.. ACKERMAN. T. P.. POLLACK, J. B. and SAGAN, C. (1983) Nuclear winter: global consequences of multiple nuclear explo- sions, Science, 222. 1253-1292.

UN CONFERENCE ON DESERTIFICATION SEC- RETARIAT (1977) Desertificarion: its Causes and Consequences. Pergamon Press, Oxford.

WALKER, J. and ROWNTREE, P. R. (1977) The effect of soil moisture on circulation and rainfall in a tropical model, (2. Jl roy. nzeteor. Sot.. 103, 29-46.

WHITE, R. M. (1979) Climate at the millennium, In: Proceeditzgs of tlze World Clirrzate Conference. pp. 2- 11. WMO. Geneva.

WIGLEY, T. M. L. and JONES, P. D. (1981) Detecting CO?-induced climatic change, Nature, 292 205-208.

WIGLEY, T. M. L.. INGRAM, M. J. AND FARMER, G. (Eds.) (1981) Climate and History: Studies in Past Climates and their Impact orz Man. Cambridge Univer- sity Press. Cambridge.

WILLIAMS, J. (1978) Carbon Dioxide, Climate and Sociefy. Pergamon Press (for International Institute for Applied Systems Analysis), Oxford.

WOODWELL, G. M., HOBBIE, J. E., HOUGHTON, R. A., MELILLO, J. M., MOORE, B., PETERSON, B. J. and SHAVER, G. R. (1983) Global defores- tation: contribution to atmospheric carbon dioxide, Science, 222, 1081-1086.

WMO (World Meteorological Organization) (1975) The Plzysical Basis of Climate and Climate Modelling, Global Atmospheric Research Programme Publication 16 (with International Council of Scientific Unions). WMO, Geneva.

WMO (1979) Proceedings of tlze World Climate Confer- ence. WMO, Geneva.

WMO (1983) Drought in Africa, report of expert group convened at request of Economic Commission for Africa. WMO, Geneva.