Overview: Eduard Brückner How constant is today‘s climate? Debate about climate change

1. The case of Eduard Brückner – solid climate research but unexpected social and technological developments. Hans von Storch & Nico Stehr

2. Overview: • Eduard Brückner • How constant is today‘s climate? • Debate about climate change • Practical importance of climate fluctuations • Conclusions • Brückner-Award 2003

3. Eduard Brückner Born July 29, 1863 in Jena, Germany, he died at the age of 65 in l927 in Vienna, Austria. He studied at the universities of Dorpat (now: Tartu, Estonia), Dresden, and Munich and completed his doctorate under Albrecht Penck in Munich with a dissertation on the ice fields in the Salzach region in Austria. On the strength of his dissertation, be was appointed professor of geography at the University of Bern. He left Switzerland in 1904 for two years at the University of Halle in Germany and finally moved to the University of Vienna. Brückner in 1890 published the first extensive book-length discussion of climate fluctuations in "historical times". He credits the head of the Bavarian meteorological services, C. Lang, with the discovery of decadal scale climate variability in a study of the climate of the Alps. Also interesting are his articles on the social consequences arising from the climate fluctuations, such as migration patterns, or on harvests, the balance of trade of countries and shifts in the political predominance of nations. Brückner's methods are mainly limited to the exploratory statistical analysis of time series in combination with what might be called common sense. He is unfamiliar with dynamical arguments (for instance, concerning the geostrophic wind) and he was unaware of theories concerning the general circulation of the atmosphere.

4. Inwieweit ist das heutige Klima konstant?How constant is today’s climate? Verhandlungen des VIII Deutsche Geographentages, Berlin 1889 “The graphical charts are based on observations from a total of 111 meteorological stations. The lustra averages of rainfall were determined for each station and expressed in percentages of the thirty-year mean of 1851 - 80; the averages of each country based on data from several stations were then smoothed according to the following formula: (a+2b+c)/4. The curves of the chart give a clearer picture of the data trend. A rise and fall of the curve by one increment refers to an increase and decrease of rain by 5%. The distance between the top and the bottom of each curve shows the amplitude of the variation, in relative not in absolute terms. The wider the gap, the greater the difference between the maximum and minimum amount of rainfall.“

5. Stations with precipitation data available to Brückner • Scotland, 16 stations (Arbroath, Laurick Castle, Loch Leven Sluice, Northesk Reservoir, Glencrose, Swanton, Fernielaw, Edingburgh, Inveresk, Haddington, Culloden, Sandwich, Arrdaroach, Castle Toward, Cameron House and Bothwell Castle). • England, 9 stations(Chillgrove, Nash Mills, Oxford, Exeter, Orleton, Podehale, Boston, Bolton and Kendal). • Northern France, 11 stations(Rouen, Paris, Vendôme, Pannetière, La Collancelle, Clamecy, Avallon, Laroche, Montbard, Poully and Dijon). • Northern Germany, 21 stations (Kleve, Trier, Köln, Boppard, Gütersloh, Frankfurt a. M., Gießen, Bremen, Kiel, Heiligenstadt, Torgau, Dresden, Stettin, Berlin, Küstrin, Frankfurt a. O., Posen, Görlitz, Breslau, Königsberg I. Pr. and Tilsit). • Austria-Hungary, 8 stations (Bodenbach, Prague, Deutschbrod, Lemberg, Kremsmünster, Klagenfurt, Vienna, and Hermannstadt). • West Russia, 6 stations (Helsingfors, St. Petersburg, Riga, Warschau, Moskau and Kiew). • East Russia, 8 stations (Lugan, Simferopol, Astrachan, Baku, Tiflis, Bogoslows, Jekatherinenburg and Slatoust).

6. West Sibiria, 1 station (Barnaul). • East of Sibiria, 3 stations(Nertschinsk, Nikolajewsk/Amur and Peking). • United States, North America, Interior, 9 stations (Toronto/Ont., Milwaukee/Wis., Detroit/Mich., Madison/Jo., Steubenville/Ohio, Marietta/Ohio, Cincinatti/Ohio, Leavenworth/Ka. and St. Louis/Miss.). • Central Italy, 7 stations (Parma, Modena, Bologna, Genua, Florence, Siena and Rome). • India, 4 stations (Madras, Calcutta, Jablapur and Bombay). • Mauritius, 1 station (S. Louis, Alfred-Observatorium.) • Australia, 7 stations (Adelaide, Bathurst, Bukelong, Deniliquin, Goulburn, Melbourne and Sydney).

9. Number of severe winters in a series of 20 winters Klimaschankungen seit 1700. E.D. Hölzel,Wien, 1890

10. “ We were able to identify general variations of the climate. At first glance it may seem unusual that these variations had escaped scientific scrutiny to this day. However, there has been speculation about them before: every now and then, based on unusual sightings at some source or body of water the view emerged in publications that the climate of certain locations, their rainfall in particular, was probably subject to periodic changes (e.g., Hann for the area of the Caspian Sea, Schweinfurth for parts of the Mediterranean countries, and most of all Fritz for many areas on the globe). The universal occurrence of the phenomenon, its global importance and simultaneous course could by strictly meteorological standards not be verified to this date, before a large number of meteorological stations had recorded the dry period of the 60s and the wet period around 1880. These general climatic variations are the key to the prevalent great confusion about the issue of climate changes, which we attempted to describe at the beginning: they are the explanation for the fact that such contradictory opinions could exist side by side: the climate changes over time first in one direction and, then again, in another — the climate fluctuates and with it fluctuate rivers, lakes and glaciers.” Inwieweit ist das heutige Klima konstant? Verhandlungen des VIII Deutsche Geographentages, Berlin 1889

11. Debate about climate change

12. Very old and wide-spread is the opinion that forests have an important impact on rainfall. And indeed, a priori, this seems quite likely. First of all forests are natural barriers to wind-driven air masses, which are then, as when encountering hills and mountains, forced to rise. No matter how light this upward drift may be, in theory it will have to lead to more condensation at its windward side. But the forest’s influence is also felt in the fact that the air above stays relatively humid. Forests slow down the swift runoff of the rainwater and store the water in the ground which is then evaporated back into the air through the tree tops. This process again must bring about an increase in precipitation above the forest, the more so as because of the strong friction between wind and forest surface and the resulting delay in air flow the moist air tends to stagnate above the forest. If forests enhance the amount and frequency of precipitation simply by being there, deforestation as part of agricultural expansion everywhere, must necessarily result in less rainfall and more frequent droughts. This view is most poignantly expressed by the saying: Man walks the earth and desert follows his steps! Klimaschankungen seit 1700. E.D. Hölzel,Wien, 1890

13. Perhaps no other area on earth has been mentioned more often in connection with the effects of deforestation on rainfall than the regions of the Mediterranean Sea, and the increasingly drier climate since pre-historic times which were interpreted as a general phenomenon, has been attributed more frequently to man’s localised destructive efforts of turning woodland into arable land. And indeed, if we compare the previously prosperous cultural life along the eastern shores of the Mediterranean Sea with the Orientals’ bare existence in those areas today, we are struck by the tremendous cultural decline and are only too readily inclined to see its causes in what saps our own energy upon arrival in the orient: the scorching dry heat. To today’s cultural leaders who live in the cool, wet northern hemisphere it seems inconceivable that the blossoming antique culture could have prospered under the present climatic conditions of the orient: the climate must have grown warmer and dryer since antiquity. Consequently, the clear-cutting of forests carried out in these regions since ancient times offers a convenient explanation: man has destroyed his own culture by destroying the forests and has devastated the land, on which he is now left with a meagre existence. A comparison between descriptions of the landscape as it used to be and as it is today appears to confirm this situation. But it was often overlooked that in antique times the descriptions of the subtropical environment were done by its inhabitants while today’s scientific efforts take mainly place in the temperate climate zones of Europe. The inhabitant of a southern country had to see the same phenomena with different eyes and painted them in different colours than the inhabitant north of the Alps. Klimaschankungen seit 1700. E.D. Hölzel,Wien, 1890

14. “ It is not surprising that under such circumstances the issue of a link between forests and climate has now and then been addressed by governments. Lately, the Italian government has been paying special attention to reforestation in Italy and its expected improvement of the climate. Father Denza emphasises the goal of such replanting efforts with these few words: It must be prevented that periods of heavy rainfall alternate with droughts. It was often believed that the climate in Germany had improved since the early ages, resulting in less cloud cover and precipitation from increasing deforestation. And, in fact, a comparison of the rather gloomy description of ‘Germania’, as for instance given by Tacitus, with the Germany of today seemed to point to a climate change; it was not taken into consideration though that this Roman’s portrayal, naturally, had to be subjectively distorted. But even in recent times multiple efforts have been made to prove a link between changes in the climate and deforestation for parts of Central Europe. Van Bebber expresses views along this line in his publication on rainfall in Germany, and so does Studniška for Bohemia. According to Wessely, in Hungary the climate of the steppe has been gradually advancing since the lifetime of Maria Theresia. In his opinion, resolute reforestation measures alone promise help in preventing the impending drought. Klimaschankungen seit 1700. E.D. Hölzel,Wien, 1890

15. In 1836 Rivière advocated the theory of deforestation for parts of southern France, namely the Vendée, the Provence, and particularly the Départment du Var, at the Academy in Paris; frost damage followed by the clearing of olive tree plantations has presumably caused a considerable reduction in rainfall and dried-up springs in the years from 1821 to 22. A similar situation exists in the former Poitou and the Department of the lower Charente according to Fleuriau de Bellevue. Actually, the question of climate change due to destruction of forests has been raised in France many times, i.e. in 1858 by Ladoucette, who pointed out before the French Chamber of Deputies that the climate of the Départements Pyrénées Orientales and the Hérault had turned dryer and warmer after the destruction of forests. Because of these reports the French legislature took a serious look at the subject of reforestation. Klimaschankungen seit 1700. E.D. Hölzel,Wien, 1890

16. In the Unites States deforestation plays an important role as well and is seen as the cause for a reduction in rainfall, which is believed to have been observed in the New England States and also in the Pacific States; F. B. Hough in his capacity as committee chairman of the American Association for Advancement of Science demands decisive steps to extend woodland in order to counteract the increasing drought. In 1873, in Vienna, the Congress for Agriculture and Forestry discussed the problem in detail; and when the Prussian house of representatives ordered a special commission to examine a proposed law pertaining to the preservation and implementation of forests for safeguarding, it pointed out that the steady decrease in the water levels of Prussian rivers was one of the most serious consequences of deforestation only to be rectified by reforestation programs. It is worth mentioning that at the same time or only a few years earlier the same concerns were raised in Russia as well and governmental circles reconsidered the issue of deforestation.” Klimaschankungen seit 1700. E.D. Hölzel,Wien, 1890

17. Practical importance of climate fluctuations. “Are climate variations so significant that they are of practical impact? Indeed they are.”

18. In dry areas in particular where water is notoriously scarce the hydrographic conditions change dramatically during periods of climatic variations. Lakes disappear during dry periods and reappear during wet ones, as for instance Lake George in New South Whales which in 1820 and again in 1876, and to a lesser extent in 1850, used to be a large lake of 12 to 18 kilometres in length, 10 kilometres in width, and 5 to 8 meters in depth, yet disappeared completely in the dry periods in between; or some central African lakes such as the Tshad, Tanganyika and Nyassa, whichat times rise so high that their overflowing waters create an outlet lasting for some years and which then lose this outlet again when the dry period begins. Rivers and creeks dry out for a full decade; swamps dry up and reappear in the next wet period. Consequently climatic variations deeply affect human life. River navigation to a great extent depends on the amount of water in the river bed which determines its depth. In those dry years around 1830 and 1860 shipping problems increased and soon a lot of speculation began about the possible cause of the lower river-water levels. In most cases the increasing practice of deforestation was found to be the source. Now we know better: it is because of climatic changes. Another way in which temperature variations are affecting traffic is through the length of time of the rivers’ freeze-up. For example, during the cold spill from 1806—1820 the Newa and the harbor of St. Petersburg remained blocked by ice for more than three weeks longer than they did during the warm period from 1821—1835. This means that during cold years harbors in a more westerly location and with shorter closure times handle part of St. Petersburg’s shipping traffic which they lose again during warm periods. Thus certain changes in shipping traffic go hand in hand with climate changes. Klimaschankungen seit 1700. E.D. Hölzel,Wien, 1890

19. Klimaschankungen seit 1700. E.D. Hölzel,Wien, 1890

21. Der Einfluß der Klimaschwankungen auf die Ernteerträge und Getreidepreise in EuropaInfluence of climate variability on harvest and grain prices in Europe. Geographische Zeitschrift, 1895

22. Klimaschwankungen und VölkerwanderungenClimate variability and mass migration Vortrag Kaiserliche Akademie der Wissenschaftern, Wien 1912 Variability of Rainfall in Relation to the Grain Crop in Prussia The Grain Crop (WZ = Wheat Crop, RO = Rye Crop) is in percentages of an average crop, i.e. in deviation from a multi-year mean ( 1 indicator = 5% deviation); rainfall (R) is also in deviations (%) from the mean (1 indicator = 4%). Variability of Rainfall and Wheat Prices in England Rainfall (R) is indicated in deviations from mean (percentages) (1 = 2.5%), the annual average wheat price (W) in Shillings per Imp. Quarter (1 = 2 sh.).

23. Variability of Rainfall and Emigration from the German Empire to the United States The curves are based on five-year totals. Rainfall is in deviations (percentages) from the multi-year mean. Emigration to the United States is in 10,000. Variability of Rainfall in the United States and Western Europe and the Total Number of Immigrants to the U.S. and from Britain. The curves are based on five year totals. The number of immigrants is given in 10,000, rainfall in deviation (percentages) from the multi-year mean..

24. CONCLUSIONS Our discussion of climate variability and climate change at the end of the 19th century leads to a number of conclusions which we consider relevant on methodical, theoretical and practical grounds: (1) The debate on natural climate variability and anthropogenic climate change is not new. A similar debate, almost forgotten today, was going on a century ago. The protagonists were in a situation similar to that of contemporary scientists. Brückner reminds us of contemporary "activist" scientists. Brückner overlooked that he did not have the expertise to predict the societal response to adverse climatic conditions, to cope with adverse conditions by improving hygienic standards (the typhoid forecast), by perfecting the railway system (the forecast concerning the ice on the rivers) or by allowing for artificial watering of agricultural land (the forecast concerning harvests). (2) One of the noteworthy features of the early debate on the nature and consequences of climate change among climatologists, geographers and meteorologists is also the degree to which even then intellectual boundaries among scientific fields prevented the participants from incorporating perspectives and findings dealing with exactly the same phenomena that had been advanced in other disciplines. After all, there had been for decades a lively and vigorous debate among philosophers and in the emerging social sciences about the impact of climatic conditions on psychological and social processes. The main assertions of this debate ultimately proved to be inconclusive and were rejected not only as one-dimensional, first at the turn of the twentieth century in France and German and later in the United States, but also as irrelevant to the distinctive claims advanced by social science discourse. That is, the domains of the physical and the social milieu had become successfully separated in science. (3) In the end a consensus emerged among climatologists that in "historical times" the global climate has been constant; that neither a warming trend nor a trend toward less precipitation can be observed. The singular preoccupation in the debate about climate variations one hundred years ago was the periodicity of observed fluctuations in temperature and precipitation, not any secular climate as signaled by an increase in the volume of CO2 in the atmosphere. That such a possibility, as the result of increased usage of fossil fuels, indeed existed was discussed alongside Brückner's 35-year-period theory in a textbook on cosmic physics by Svante A. Arrhenius (1903). However, none of the climatologists of the day took up the challenge. Instead, they agreed that climate change was not a significant matter and soon other issues began to dominate scientific discussions and public discourse.

25. Brückner-Award 2003 Die Klimaforschung hat eine lange Tradition und hat eine Reihe von Metamorphosen durchgemacht. In klassischen Zeiten stand die Wirkung des mittleren atmosphärischen Zustandes auf den Menschen im Vordergrund, später entstand die Klimatographie und schließlich eine Palette von sich zumeist unabhängig entwickelnden disziplinären Sichtweisen in Fächern wie Geologie, Meteorologie, Geographie oder Ozeanographie. Erst unter dem Eindruck drohender anthropogener Klimaänderungen im letzten Jahrzehnt und dem unmittelbaren Beratungsbedarf von Politik und Gesellschaft beginnen diese Disziplinen sich aufeinander zu zu bewegen. Tatsächlich kann das "Klimaproblem" nicht als Forschungsgegenstand etwa vorrangig der Meteorologie verstanden werden. Einerseits muß das Verstehen des Klimas als geophysikalische Herausforderung gesehen werden. Andererseits wird die Wahrnehmung und tradiertes Wissen von Klima Gegenstand sozial- und kulturwissenschaftlicher Forschung, weil Klima Gegenstand öffentlichen Interesses und öffentlicher Sorge geworden ist. Um diesen Prozeß der interdisziplinären Verbreiterung der Klimaforschung zu fördern, wird anläßlich der 6. Deutschen Klimatagung im September 2003 zum zweiten Male der Eduard Brückner-Preis für herausragende interdisziplinäre Leistungen in der Klimaforschung vergeben. Das Preisgeld in Höhe von 1500 € ist von Inter-Research, dem Verleger der Zeitschrift "Climate Research", gespendet worden. Der Preisträger wird von den aus den Professoren Egger, Negendank, Sündermann, von Storch und Wanner nach Vorschlägen aus dem Kreis der Klimaforscher ausgewählt. Vorschläge werden in schriftlicher Form bis zum 1. August 2003 an Hans von Storch (storch@gkss.de) erbeten. Erster Brücker-PreisträgerChristian Pfister, Klimahistoriker, Bern

26. Zahllos sind die Hypothesen und Theorien, die über Änderungen des Klimas in der Vergangenheit aufgestellt wurden und naturgemäß mehr oder minder lebhaft das Interesse weiterer Kreise in Anspruch nahmen, lässt doch der strenge Nachweis einer in vergangenen Zeiten vor sich gegangenen Änderung des Klimas sofort den Gedanken an die Möglichkeit einer zukünftigen Änderung auftauchen; eine solche aber könnte sich nicht ohne einschneidende Wirkung auf das wirtschaftliche Leben der Völker vollziehen. Brückner (1890:2)