Transcript Klimaschankungen seit 1700.

A historical dimension of
climate and climate change
Hans von Storch
Institute for Coastal Research
GKSS Research Center
Germany
Stockholm, 16 October 2006
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
Thinking about climate, climate change and society
(1) ideas about anthropogenic
influence on climate
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
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
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
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
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
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
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
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.
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
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
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
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
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
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
Damming the Congo
River at Stanley Hill
to irrigate the Sahara
with a “Second Nile”
Note also dams
throughout the
Mediterranean
From Jim Fleming
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
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
1954
From Jim Fleming
From Jim Fleming
From Jim Fleming
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
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
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
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
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
Utopian Geoengineering?
From Jim Fleming
Thinking about climate, climate change and society
(2) ideas about the influence
of climate and climate change
on humans and societies
Map of „mental energy“ conditioned by climatic
conditions
E. Huntington
Distribution of civilizations in 1916, according to
expert opinion.
Davies‘ (1923, 1929
and 1932) „nose
index“ derived
from observations
and estimated
from temperature
and humidity data.
The case of
Eduard Brückner
– solid climate
research but
unexpected
social and
technological
developments.
Hans von Storch
& Nico Stehr
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.
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.
Stations with precipitation data available to Brückner
•
Scotland, 16 stations
•
England, 9 stations
•
Northern France, 11 stations
•
Northern Germany, 21 stations
•
Austria-Hungary, 8 stations
•
West Russia, 6 stations
•
East Russia, 8 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).
(Chillgrove, Nash Mills, Oxford, Exeter, Orleton, Podehale, Boston, Bolton and Kendal).
(Rouen, Paris, Vendôme, Pannetière, La Collancelle, Clamecy, Avallon, Laroche, Montbard, Poully and Dijon).
(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).
(Bodenbach, Prague, Deutschbrod, Lemberg, Kremsmünster, Klagenfurt, Vienna, and Hermannstadt).
(Helsingfors, St. Petersburg, Riga, Warschau, Moskau and Kiew).
(Lugan, Simferopol, Astrachan, Baku, Tiflis, Bogoslows, Jekatherinenburg and Slatoust).
•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).
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
1831/35
1881/85
Number of severe winters in a series of
20 winters in Central Europe
10
8
6
4
2
0
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
Klimaschankungen seit 1700.
E.D. Hölzel,Wien, 1890
Practical importance of climate fluctuations.
“Are climate variations so significant that they
are of practical impact? Indeed they are.”
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, which at 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
Anomalies of length of ice-free periods
1801-05
30
20
10
0
-10
173 41-- 46-- 51-- 56-- 61-- 66-- 71-- 76-- 81-- 86-- 91-- 96-- 180 06-- 11-- 16-- 21-- 26-- 31-- 36-- 41-- 46-- 51-- 56-- 61-- 66-- 71-- 76-6-- 45 50 55 60 65 70 75 80 85 90 95 00 1-- 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
40
05
-20
-30
1736-40
Siberia
Ural
N.-Russia
Baltic Provinces
SE-Russia
SW-Russia
StatesN-America
Mean Values
Klimaschankungen seit 1700.
E.D. Hölzel,Wien, 1890
The case of
typhoid
Continental
climate
Precip crop prod.
Der Einfluß der Klimaschwankungen auf die Ernteerträge und Getreidepreise in Europa
Influence of climate variability on harvest and grain prices in Europe.
Geographische Zeitschrift, 1895
Klimaschwankungen und Völkerwanderungen
Climate variability and mass migration
Vortrag Kaiserliche Akademie der Wissenschaftern,
Wien 1912
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.).
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 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..
… and today?
• Certain culturally constructed views of
climate change
- drastic signs (palms)
- disaster
• How is the relationship of climate and
society?
Hasselmann, 1990
Perceived Environment and Society (PES) model
Stehr and von Storch, 1993