A historical dimension of climate and climate change

1. A historical dimension of climate and climate change Hans von StorchInstitute for Coastal ResearchGKSS Research CenterGermany Stockholm, 16 October 2006

2. Historical dimension • Climate in historical times - intellectually appealing- relevant for assessing ongoing climate change whether it is anthropogenic or entirely caused by natural processes • Thinking about climate, climate change and society(1) ideas about anthropogenic influence on climate(2) ideas about the influence of climate and climate change on humans and societies

3. Thinking about climate, climate change and society (1) ideas about anthropogenic influence on climate

4. A history of human perceptions of anthropogenic climate change in the past 1000 years Hans von Storch and Nico Stehr with several illustrations from Jim Flemming

5. Religious Interpretations • Religious interpretations of climate anomalies, such as the prolonged wet period in England in the early 14th century, explained the adverse climatic conditions as the divine response to people’s life-style. • In medieval times, for instance, it was proposed that climatic anomalies, or extreme events, were a punishment for parishes which were too tolerant of witches. Of course, witches were believed to be able to directly cause adverse weather. • This practice is also used nowadays. A recent example has been reported by Berlingske Tidende, 11 April 1998 about the religious interpretations of violent tornadoes in Alabama during Eastern 1998. 1

6. Improving climate by human stewardship • Our oldest case documented by contemporary scientific writing refers to the climate of the North American colonies (Williamson, 1771). The physician Williamson analyzed the changes of climate, and related them to the clearing of the landscape by the settlers. • This is a case in which human action was perceived as having a beneficial impact on climate. • More cases during the medieval times, related to colonization by monks, are described by Glacken (1967). 2-4

7. Tambora 1816 and lightning rods • In many parts of Europe, the summer of 1816 was unusually wet, presumably because of the eruption of the volcano Tambora. • However, people ascribed the adverse conditions to the new practice of using lightning conductors. The case is documented in two articles published in the newspaper Neue Züricher Zeitung (21 June and 9 July 1816). The authorities called the concerns unsubstantiated and issued grave warnings concerning violent and illegal acts against the conductors. • Interestingly, it is mentioned that some years earlier in Germany, people blamed the conductors for being responsible for a drought. 6

8. Debate about climate change – in the late 19th century • In the 19th century scientists in Europe and in North America were confronted with the concept that the climate would be constant on historical time scales; however, scientists found significant differences between mean precipitation and temperature when averaged over different multi-year periods (e.g. Brückner, 1890). • Also, scientists claimed that the water levels of rivers would fall continuously. This led to questioning of the assumption of constant climatic conditions — in modern terms: interdecadal natural variability — and, alternatively, to the hypothesis that the observed changes are caused by human activities, mainly deforestation or reforestation. • A debate was hold about two alternative explanations, namely a systematic climate change mainly related to deforestation, or natural fluctuations on time scales of decades of years. It seems that the majority adopted the concept of man-made causes over the natural variability hypothesis. 7

9. 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

10. In 1836 Rivière advocated the theory of deforestation for parts of southern France 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. The question of climate change due to destruction of forests has been raised in France many times, e.g. it was 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. 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

11. List of historical cases of perceived anthropogenic cimate changes Our list should not be mistaken as an attempt to belittle the presently voiced concerns about anthropogenic climate change.

12. Influence of battles, radio, nukes • There are reports that both the extensive gun-fire during the first World War. • Claims have been made that already in classical times battles had caused rainfall. • The initiation of short wave trans-Atlantic radio communication were blamed for wet summers in the 1910s and 20s. • After World War II, the new practice of exploding nuclear devices in the atmosphere caused widespread concern about the climatic implications of these experiments. According to Kempton’s analysis, even nowadays many lay-people are concerned about this link. 8

13. CO2 – first round of attention • In the first part of the 20th century a remarkable warming took place in large parts of the world. • In 1933, this warming was documented, and the uneasy question „Is the climate changing?“ was put forward in Monthly Weather Review (Kincer, 1933). • Some years later, Callendar (1938) related the warming to human emissions of carbon dioxide into the atmosphere, a mechanism described some 40 years earlier by Arrhenius (1898). Flohn (1941) also brought this line of reasoning into the scientific debate. • Interestingly, Arrhenius himself stated that anthropogenic emissions of CO2 would cause an significant climate change only after several hundred years (Arrhenius, 1903). • In the 1940s global mean temperatures began to fall – which eventually led to claims that Earth was heading towards a new Ice Age. 9

14. The cooling • After World War II scientists noticed a cooling and some speculated about whether this cooling was the first indication of a new Ice Age, possibly brought on by human actions, mostly emissions of dust and industrial pollution. • It was speculated that human pollution would increase by a factor of as much as 8 which could increase the opacity of the atmosphere within hundred years by 400%. This would reduce incoming sun light causing the global mean temperature to sink by 3.5 C. Such a cooling would almost certainly be enough to force Earth into a new Ice Age (Rasool and Schneider, 1971). • The prospect was illustrated with the words: „Between 1880 and 1950, Earth’s climate was the warmest it has been in five thousand years. ... It was a time of optimism. ... The optimism has shriveled in the first chill of the cooling. Since the 1940s winters have become subtly longer, rains less dependable, storms more frequent throughout the world.“ (Ponte, 1974). 10

15. Siberian rivers and other Sovjet ideas • In Russia, plans for re-routing Siberian rivers southward have been discussed since the beginning of this century. The plans visualize benefits in supplying semi-arid regions with water, and an improved regional climate. • A byproduct was thought to be an ice-free Arctic ocean because of the reduced fresh water input from the rivers. This would shorten the winters and extend the growing season; the increase of evaporation from the open water would transform the Arctic climate into a maritime climate with moderate temperatures and busy harbors along the Soviet Union’s North coast. • Such plans were formally adopted in 1976 at the 25th Assembly of the Soviet Communist Party. • Scientists from the West as well as from the Soviet Union opposed these plans and warned that the formation of an ice-free Arctic could significantly affect the global ocean circulation and thus global climate. Eventually, the plans were abandoned although a more careful analyses indicated that the probability of melting the Arctic sea ice associated with a rerouting of the rivers was overestimated. 11

16. Ring of dust particles in orbit to increase solar energy absorption, melt the ice caps and illuminate the arctic circle — proposed separately by Gorodsky and Cherenkov in 1958 and 1960. From Jim Fleming

17. Rerouting ocean currents, artificial lakes • The New York engineer Riker suggested in 1912 changing the Gulf Stream with the purpose of improving the climate not only in North America but also the Arctic and Europe. Riker’s idea was: „A simple jetty 200 miles long could be built from Cape Race on Newfoundland to a point just beyond the underwater Grand Banks would keep the Labrador Current and the Gulf Stream apart ... Half of the Gulf Streamwould throw increased warmth against Northern Europe, and half would thrust into the Arctic... The benefits of this would be enormous .... Fog would disappear, ... all ice in the Arctic would melt. The melting of the Arctic would improve the world climate in two ways. ... Europe and North America would be freed of chilling storms and icy ocean currents... And without the North Polar ice, the surviving ice pack at the South Pole would become the heaviest part of our planet. Centrifugal force would then tip the Earth ... With the Northern hemisphere tipped more towards the sun, Europe and North America could expect warmer climate.“. • The idea of modifying ocean currents was later pursued by scientists from the USA, USSR and other nations. In most cases, these schemes revolved around the building of a dam, which would for instance block the flow through the Bering Strait. 12

18. Damming the Congo River at Stanley Hill to irrigate the Sahara with a “Second Nile” Note also dams throughout the Mediterranean From Jim Fleming

19. Ocean Currents Divert the Gulf Stream with a dam between Florida and Cuba? —Ridger Divert the Laborador Current in Newfoundland? Dam the Behring Straits to divert Atlantic waters to the Pacific and melt the Arctic sea ice? — Borisov

23. Military use • Close to the idea of climate engineering is the military use of climate modifications. The idea to change the course of the Gulf Stream had been put forward already in the 18th century by Benjamin Franklin, who envisaged a northward diversion of the Gulf Stream as a powerful weapon against the British Empire. • A perceived attack using climate as a weapon is a purported Soviet plan in the 1950s to build a „jetty 50 miles or more long out from near the eastern tip of Siberia. The jetty would contain several atomic powered pumping stations that would push cold Arctic waters down through the Bering Strait. This would ... inject increasing amounts of icy waters into the ocean current that flows down the west coast of Canada and the United States. The result would be colder, more stormy weather throughout North America and enormous losses to the American economy in agriculture, work days and storm damage.“. • Concern about the development of climate weapons lead to a series of diplomatic discussions. During a summit meeting 1974 the United States and the Soviet Union issued a Joint Draft Treaty: „Each State Party to this Convention undertakes not to engage in military or other hostile use of environmental modification techniques having widespread, long-lasting or severe effects as the means of destruction, damage or injury ... the term ‘environmental modification techniques’ refers to any technique for changing – through the deliberate manipulation of natural processes – the dynamics, composition of the Earth, including its biota, lithosphere, hydrosphere and atmosphere ... so as to cause such effects as ... changes in weather pattern, ...in climate patterns, or in ocean currents.“ 13

24. 1954 From Jim Fleming

25. From Jim Fleming

26. From Jim Fleming

28. Supersonic transport • In the 1960s and 70s aircraft industries in the USA, Europe and Soviet Union designed supersonic civil air planes. • These plans provoked substantial criticism. Scientist argued that the exhaust from such planes would damage the ozone layer in the stratosphere and the climate in general. In the USA the plans were stopped, but in Europe the Concorde was built and in the Soviet Union the TU 144. • Of course, numerous military supersonic aircraft are nowadays cruising the lower stratosphere. • For many years, the discussion about the impact of air traffic on the climate ceased. But in the early 1990s the topic re-entered the public debate, this time regarding high-flying conventional jet liners. The focus of concern is the effect of contrails and exhaust gases on the radiative balance of Earth. Scientists regard present effects from these sources as minor compared to other effects. However, some argue that with present projections of future passenger numbers and technology the effect maybe or will be significant. 14

29. Space traffic • A popular, but for natural scientists somewhat surprising mechanism links space traffic to a deteriorating global climate. In Kempton et al.’s (1995) interviews with lay people, this mechanism is mentioned several times. 43% of the respondents in Kempton’s survey considered the statement „there may be a link between the changes in the weather and all the rockets they have fired into outer space“ plausible. 15

30. deforestation, part II • The ongoing deforestation of tropical forests is of great concern to many people, who are afraid not only of reduction in the variety of species but also of changes in global climate (Kempton et al., 1995; Dunlap et al., 1993). • Model calculations indicate that these land use modifications cause significant local and regional changes whereas in most model calculations global effects are marginal. • Interestingly, similar results were obtained for the climatic implications of the transformation of the North American wilderness into agricultural land (Copeland et al., 1996). 16

31. Aerosols, nuclear winter • Anthropogenic aerosols are considered powerful agents for changing the global climate. • One scenario deals with the emission of aerosols mainly from burning forests and fossil fuels. A dramatic version is that of „nuclear winter“ – in which it was assumed that the explosion of a multitude of nuclear bombs in a future war would create a high flying veil of soot particles which would effectively shut off solar radiation and cause a collapse of the biosphere. • Support came from a number of computer simulation. The ignition of the Kuwait oil wells in the aftermath of the 1991 Gulf War led some scientists to expect a minor nuclear winter, particularly with respect to the Indian Monsoon. It turned out that the effect was severe locally but insignificant on the larger scales. 17

32. Break down of Gulf Stream • A new line of concern, especially in Europe, refers to the stability of the Gulf Stream. • Ocean models exhibit a markedly nonlinear behavior of the Atlantic circulation with two stable states, one with an active Gulf stream and another with a weakened northward transport moderating the European climate. Both states are stable within a certain range of conditions, but when the system is brought to the margins of these ranges, it can switch abruptly to the other state. • Paleoclimatic reconstructions using evidence from ice cores and other indirect sources support the existence of such stable states and frequent rapid changes from one state to another. During the present interglacial period from about 10,000 years go to the present, such rapid climate changes have not been detected. • In the global warming debate the risk of a „collapse“ of the Gulf Stream is put forward. While the globe is becoming warmer, Europe and Northeast America would experience colder conditions with the possibility of a new ice age. • Not only global warming is presented as a human lever for terminating the Gulf Stream. Another hypothesis was published by the Transactions of the American Geophysical Union. The human culprit was the Assuan Dam in Egypt which would reduce the flow of fresh water into the Mediterranean Sea. This reduction along with enhanced evaporation caused by global warming would result in a saltier outflow from the Mediterranean Sea into the Atlantic eventually causing the Gulf Stream to flip over. 18

33. Utopian Geoengineering? From Jim Fleming

34. Thinking about climate, climate change and society (2) ideas about the influence of climate and climate change on humans and societies

35. Map of „mental energy“ conditioned by climatic conditions E. Huntington Distribution of civilizations in 1916, according to expert opinion.

36. Davies‘ (1923, 1929 and 1932) „nose index“ derived from observations and estimated from temperature and humidity data.

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

38. 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.

39. Inwieweit ist das heutige Klima konstant?How constant is today’s climate? Verhandlungen des VIII Deutsche Geographentages, Berlin 1889 An analysis of climate variations since about 1700 based on data from a total of 111 meteorological stations distributed throughout the world. Detection of synchronous inter-decadal variability.

40. 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).

41. 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).

42. 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. Secular variations of rainfall – 10 sections from East to West 1831/35 to 1881/85 E Sibiria

43. 1831/351881/85

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

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

46. 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

47. 1801-05 1736-40 Klimaschankungen seit 1700. E.D. Hölzel,Wien, 1890

48. The case of typhoid

49. Continental climate Precip crop prod. Der Einfluß der Klimaschwankungen auf die Ernteerträge und Getreidepreise in EuropaInfluence of climate variability on harvest and grain prices in Europe. Geographische Zeitschrift, 1895

50. 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.).