Climate4you update October 2011www.climate4you.com

October 2011 global surface air temperature overview

1

October 2011 surface air temperature compared to the average 1998-2006. Green-yellow-red colours indicate areas with higher
temperature than the 1998-2006 average, while blue colours indicate lower than average temperatures. Data source: Goddard Institutefor Space Studies (GISS)

Comments to the October 2011 global surface air temperature overview
General: This newsletter contains graphs showing a
selection of key meteorological variables for the
past month. All temperatures are given in degrees
Celsius.

2

In the above maps showing the geographical patternof surface air temperatures, the period 1998-2006 is
used as reference period. The reason for comparing
with this recent period instead of the official WMO‘normal’ period 1961-1990, is that the latter period
is affected by the relatively cold period 1945-1980.
Almost any comparison with such a low averagevalue will therefore appear as high or warm, and it
will be difficult to decide if and where modern
surface air temperatures are increasing or decreasingat the moment. Comparing with a more recent
period overcomes this problem. In addition to thisconsideration, the recent temperature development
suggests that the time window 1998-2006 mayroughly represent a global temperature peak. If so,
negative temperature anomalies will gradually
become more and more widespread as time goes on.
However, if positive anomalies instead gradually
become more widespread, this reference period only
represented a temperature plateau.
In the other diagrams in this newsletter the thin line
represents the monthly global average value, andthe thick line indicate a simple running average, inmost cases a simple moving 37-month average,
nearly corresponding to a three year average. The
37-month average is calculated from values
covering a range from 18 month before to
18 months after, with equal weight for every month.
The year 1979 has been chosen as starting point inmany diagrams, as this roughly corresponds to boththe beginning of satellite observations and the onsetof the late 20th century warming period. However,
several of the records have a much longer record
length, which may be inspected in grater detail on
www.Climate4you.com.

The average global surface air temperatures October
2011:
The Northern Hemisphere was characterised byhigh regional variability. Warmer than 1998-2006
average temperatures extended across most ofnorthern Russia, most of Siberia and Canada. A
prominent hotspot existed over northern Siberia andadjoining parts of the Arctic Ocean.
The Southern Hemisphere in general was close to orslightly below average 1998-2006 conditions. Mostof South America, southern Africa and Indonesia
had below average temperatures. Australia ingeneral was to average.
Near Equator temperatures conditions were in
general below average 1998-2006 conditions.
The Arctic was characterized by a high variability of
average surface air temperatures. Most of Siberia
and Russia had above average temperatures, andonly eastern Siberia saw below averagetemperature. Also most of Alaska and the Canadian
Arctic sector had above average temperature. Only
Greenland had below average temperature in
October. The marked thermal contrast near the
North Pole is a mathematical artefact, derived fromthe GISS interpolation procedure, and should be
ignored.
Most of the Antarctic continent experienced below
average temperatures. Only the central part of thecontinent experienced above average temperatures.
The global oceanic heat content has now for several
years been almost stable, at least since 2003/2004(page 10).
The global sea level is not doing very much, either,since 2009 (page 17).

Most diagrams shown in this newsletter are also available for download on www.climate4you.com

Lower troposphere temperature from satellites, updated to October 2011

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Global monthly average lower troposphere temperature (thin line) since 1979 according to University of Alabama at Huntsville, USA.
The thick line is the simple running 37 month average.

Global monthly average lower troposphere temperature (thin line) since 1979 according to according to Remote Sensing Systems (RSS),
USA. The thick line is the simple running 37 month average.

Global surface air temperature, updated to October 2011

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Global monthly average surface air temperature (thin line) since 1979 according to according to the Hadley Centre for Climate
Prediction and Research and the University of East Anglia's Climatic Research Unit (CRU), UK. The thick line is the simple running 37
month average.

Global monthly average surface air temperature (thin line) since 1979 according to according to the Goddard Institute for Space Studies(GISS), at Columbia University, New York City, USA. The thick line is the simple running 37 month average.

Global monthly average surface air temperature since 1979 according to according to the National Climatic Data Center (NCDC), USA.
The thick line is the simple running 37 month average.

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A note on data record stability:

The most stable temperature record over time of the

All the above temperature estimates display changes

five global records shown above is the HadCRUT3

when one compare with previous monthly data sets,

series.

not only for the most recent months as a result ofadditional data being added, but actually for all

The interested reader may find more on the issue ofmonths back to the very beginning of the records.

temporal stability (or lack of this) on

Presumably this reflects recognition of errors andwww.climate4you (go to: Global Temperature,changes in the averaging procedure followed.

followed by Temporal Stability).

All in one, updated to October 2011

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Superimposed plot of all five global monthly temperature estimates shown above. As the base period differs forthe different temperature estimates, they have all been normalised by comparing to the average value of theirinitial 120 months (10 years) from January 1979 to December 1988. The heavy black line represents the simple
running 37 month (c. 3 year) mean of the average of all five temperature records. The numbers shown in thelower right corner represent the temperature anomaly relative to the 1979-1988 average.

It should be kept in mind that satellite- and surface-

All five global temperature estimates presently

based temperature estimates are derived fromshow stagnation, at least since 2002. There has beendifferent

that

no increase in global air temperature since 1998,

comparing them directly as done in the diagram

which however was affected by the oceanographic

above therefore in principle may be problematical.

El Niño event. This stagnation does not exclude the

However, as both types of estimate often are

possibility that global temperatures will begin to

discussedmayincrease again later. On the other hand, it also

nevertheless be of some interest. In fact, theremain a possibility that Earth just now is passing a

different types of temperature estimates appear totemperature peak, and that global temperatures willagree quite well as to the overall temperature

begin to decrease within the coming years. Timevariations on a 2-3 year scale, although on a shorter

will show which of these two possibilities is correct.

types

of

together,measurements,

the

above

and

diagramtime scale there may be considerable differences
between the individual records.

Global sea surface temperature, updated to the end of October 20117

Sea surface temperature anomaly at 29 October 2011. Map source: National Centers for Environmental
Prediction (NOAA).

Relative cold surface water dominates the regions
near Equator, especially in the eastern Pacific
Ocean, and represents remnants of the previous La
Niña, fading away in the spring 2011. Apparently a
new El Niño is not going to materialise, and surface
temperatures are dropping. Because of the large
surface areas involved near Equator, the relatively
cold surface water in these regions affects the global
atmospheric temperature.
The significance of any warming or cooling seen insurface air temperatures should not be over stated.

Whenever Earth experiences cold La Niña or warm
El Niño episodes (Pacific Ocean) major heatexchanges takes place between the Pacific Ocean
and the atmosphere above, eventually showing up in
estimates of the global air temperature. However,this does not reflect similar changes in the total heat
content of the atmosphere-ocean system. In fact, netchanges may be small, as the above heat exchange
mainly reflects a redistribution of energy between
ocean and atmosphere. What matters is the overalltemperature development when seen over a numberof years.

Global monthly average lower troposphere temperature over oceans (thin line) since 1979 according to University of Alabama at
Huntsville, USA. The thick line is the simple running 37 month average.

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Global monthly average sea surface temperature since 1979 according to University of East Anglia's Climatic Research Unit (CRU), UK.
Base period: 1961-1990. The thick line is the simple running 37 month average.

Global monthly average sea surface temperature since 1979 according to the National Climatic Data Center (NCDC), USA. Base period:
1901-2000. The thick line is the simple running 37 month average.

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Global ocean heat content, updated to June 2011

Global monthly heat content anomaly (GJ/m2) in the uppermost 700 m of the oceans since January 1979. Data source: National

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Oceanographic Data Center(NODC).

Global monthly heat content anomaly (GJ/m2) in the uppermost 700 m of the oceans since January 1955. Data source: National
Oceanographic Data Center(NODC).

Arctic and Antarctic lower troposphere temperature, updated to October 201111

Global monthly average lower troposphere temperature since 1979 for the North Pole and South Pole regions, based on satellite
observations (University of Alabama at Huntsville, USA). The thick line is the simple running 37 month average, nearly corresponding toa running 3 yr average.

Arctic and Antarctic surface air temperature, updated to September 201112

Diagram showing Arctic monthly surface air temperature anomaly 70-90oN since January 2000, in relation to the WMO reference“normal” period 1961-1990. The thin blue line shows the monthly temperature anomaly, while the thicker red line shows the running 13
month average. Data provided by the Hadley Centre for Climate Prediction and Research and the University of East Anglia's Climatic
Research Unit (CRU), UK.

Diagram showing Antarctic monthly surface air temperature anomaly 70-90oS since January 2000, in relation to the WMO reference“normal” period 1961-1990. The thin blue line shows the monthly temperature anomaly, while the thicker red line shows the running 13
month average. Data provided by the Hadley Centre for Climate Prediction and Research and the University of East Anglia's Climatic
Research Unit (CRU), UK.

Diagram showing Arctic monthly surface air temperature anomaly 70-90oN since January 1957, in relation to the WMO reference“normal” period 1961-1990. The year 1957 has been chosen as starting year, to ensure easy comparison with the maximum length of therealistic Antarctic temperature record shown below. The thin blue line shows the monthly temperature anomaly, while the thicker red line
shows the running 13 month average. Data provided by the Hadley Centre for Climate Prediction and Research and the University of
East Anglia's Climatic Research Unit (CRU), UK.

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Diagram showing Antarctic monthly surface air temperature anomaly 70-90oS since January 1957, in relation to the WMO reference“normal” period 1961-1990. The year 1957 was an international geophysical year, and several meteorological stations were establishedin the Antarctic because of this. Before 1957, the meteorological coverage of the Antarctic continent is poor. The thin blue line shows themonthly temperature anomaly, while the thicker red line shows the running 13 month average. Data provided by the Hadley Centre for
Climate Prediction and Research and the University of East Anglia's Climatic Research Unit (CRU), UK.

14

Diagram showing Arctic monthly surface air temperature anomaly 70-90oN since January 1900, in relation to the WMO reference“normal” period 1961-1990. The thin blue line shows the monthly temperature anomaly, while the thicker red line shows the running 13
month average. In general, the range of monthly temperature variations decreases throughout the first 30-50 years of the record,reflecting the increasing number of meteorological stations north of 70oN over time. Especially the period from about 1930 saw theestablishment of many new Arctic meteorological stations, first in Russia and Siberia, and following the 2nd World War, also in North
America. Because of the relatively small number of stations before 1930, details in the early part of the Arctic temperature record should
not be over interpreted. The rapid Arctic warming around 1920 is, however, clearly visible, and is also documented by other sources of
information. The period since 2000 is warm, about as warm as the period 1930-1940. Data provided by the Hadley Centre for Climate
Prediction and Research and the University of East Anglia's Climatic Research Unit (CRU), UKIn general, the Arctic temperature record appears to beless variable than the Antarctic record, presumably atleast partly due to the higher number of meteorologicalstations north of 70oN, compared to the number ofstations south of 70oS.
As data coverage is sparse in the Polar Regions, theprocedure of Gillet et al. 2008 has been followed,
giving equal weight to data in each 5ox5o grid cell whencalculating means, with no weighting by the surface areasof the individual grid dells.
Literature:
Gillett, N.P., Stone, D.A., Stott, P.A., Nozawa, T.,
Karpechko, A.Y.U., Hegerl, G.C., Wehner, M.F. andJones, P.D. 2008. Attribution of polar warming to human
influence. Nature Geoscience 1, 750-754.

Arctic and Antarctic sea ice, updated to October 2011

Graphs showing monthly Antarctic, Arctic and global sea ice extent since November 1978, according to the National Snow and Ice data
Center (NSIDC).

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Graph showing daily Arctic sea ice extent since June 2002, to October 3, 2011, by courtesy of Japan Aerospace Exploration Agency(JAXA). Please note that this diagram is not updated beyond 3 October 2011 due to the suspension of AMSR-E observation.

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Northern hemisphere sea ice thickness on 30 October 2011 according to the Arctic Cap Nowcast/Forecast System (ACNFS), US Naval
Research Laboratory. Thickness scale (m) is shown to the right.

Global sea level, updated to September 2011

Globa lmonthly sea level since late 1992 according to the Colorado Center for Astrodynamics Research at University of Colorado at
Boulder, USA. The thick line is the simple running 37 observation average, nearly corresponding to a running 3 yr average.

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Forecasted change of global sea level until year 2100, based on simple extrapolation of measurements done by the Colorado Center for
Astrodynamics Research at University of Colorado at Boulder, USA. The thick line is the simple running 3 yr average forecast for sea
level change until year 2100. Based on this (thick line), the present empirical forecast of sea level change until 2100 is about +20 cm.

Atmospheric CO2, updated to October 201118

Monthly amount of atmospheric CO2 (above) and annual growth rate (below; average last 12 months minus average preceding 12months) of atmospheric CO2 since 1959, according to data provided by the Mauna Loa Observatory, Hawaii, USA. The thick line is thesimple running 37 observation average, nearly corresponding to a running 3 yr average.

Northern Hemisphere weekly snow cover, updated to the end of October 2011

Northern hemisphere weekly snow cover since January 2000 according to Rutgers University Global Snow Laboratory. The thin line is
the weekly data, and the thick line is the running 53 week average (approximately 1 year).

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Northern hemisphere weekly snow cover since October 1966 according to Rutgers University Global Snow Laboratory. The thin line is
the weekly data, and the thick line is the running 53 week average (approximately 1 year). The running average is not calculated before
1971 because of some data irregularities in this early period.

Global surface air temperature and atmospheric CO2, updated to October 2011

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Diagrams showing HadCRUT3, GISS, and NCDC monthly global surface air temperature estimates (blue) and the monthly
atmospheric CO2 content (red) according to the Mauna Loa Observatory, Hawaii. The Mauna Loa data series begins inMarch 1958, and 1958 has therefore been chosen as starting year for the diagrams. Reconstructions of past atmospheric
CO2 concentrations (before 1958) are not incorporated in this diagram, as such past CO 2 values are derived by othermeans (ice cores, stomata, or older measurements using different methodology, and therefore are not directly comparablewith modern atmospheric measurements. The dotted grey line indicates the approximate linear temperature trend, and theboxes in the lower part of the diagram indicate the relation between atmospheric CO 2 and global surface air temperature,negative or positive.

Most climate models assume the greenhouse gas
carbon dioxide CO2 to influence significantly upon
global temperature. Thus, it is relevant to compare
the different global temperature records withmeasurements of atmospheric CO2, as shown in the
diagrams above. Any comparison, however, should
not be made on a monthly or annual basis, but for alonger time period, as other effects (oceanographic,
clouds, volcanic, etc.) may well override thepotential influence of CO2 on short time scales suchas just a few years.
It is of cause equally inappropriate to present new
meteorological record values, whether daily,
monthly or annual, as support for the hypothesis

ascribing high importance of atmospheric CO2 for
global temperatures. Any such short-period
meteorological record value may well be the resultof other phenomena than atmospheric CO2.
What exactly defines the critical length of a relevanttime period to consider for evaluating the allegedhigh importance of CO2 remains elusive. However,the length of the critical period must be inversely
proportional to the importance of CO2 on the global
temperature, including possible feedback effects. So
if the net effect of CO2 is strong, the length of thecritical period is short, and vice versa.

After about 10 years of global temperature increase
following global cooling 1940-1978, IPCC wasestablished in 1988. Presumably, several scientists
interested in climate in 1988 felt intuitively that
their empirical and theoretical understanding ofclimate dynamics was sufficient to conclude about
the high importance of CO2 for global temperature.
However, for obtaining public and political support
for the CO2-hyphotesis the 10 year warming periodleading up to 1988 in all likelihood was important.
Had the global temperature instead been decreasing,
political and public support for the CO2-hypothesis
would have been difficult to obtain. Adopting thisapproach as to critical time length, the varying
relation (positive or negative) between global
temperature and atmospheric CO2 has been
indicated in the lower panels of the three diagrams
above.

Last 20 year surface temperature changes, updated to October 2011

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Last 20 years global monthly average surface air temperature according to Hadley CRUT, a cooperative effort between the
Hadley Centre for Climate Prediction and Research and the University of East Anglia's Climatic Research Unit (CRU), UK.
The thin blue line represents the monthly values. The thick red line is the linear fit, with 95% confidence intervals indicatedby the two thin red lines. The thick green line represents a 5-degree polynomial fit, with 95% confidence intervals indicatedby the two thin green lines. A few key statistics is given in the lower part of the diagram. Last month included in analysis:
October 2011.

From time to time it is debated if the global surface temperature is increasing, or if the temperature has leveledout during the last 10-15 years. The above diagram may be useful in this context. If nothing else, it demonstrates
the differences between two different statistical approaches to determine recent temperature trends.

Climate and history; one example among many

384-322 BC; Aristotle's views on weather and climate

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Marble bust of Aristotle (left). Roman copy after a Greek bronze original by Lysippus c. 330 BC. Geocentriccelestial spheres (center); Peter Apian's Cosmographia (Antwerp, 1539). Right picture: Plato (left) and Aristotle(right), a detail of The School of Athens, a fresco by Raphael. Aristotle gestures to the earth, representing his
belief in knowledge through empirical observation and experience, while holding a copy of his Nicomachean
Ethics in his hand, whilst Plato gestures to the heavens, representing his belief in The Forms.

Aristotle (384-322 BC) was a Greek philosopher, astudent of Plato and later teacher of Alexander theGreat. Aristotle is one of the most important
founding figures in Western philosophy, and his
views on the physical sciences profoundly shaped
medieval scholarship, and their influence extended
well into the Renaissance, although they were
ultimately replaced by Newtonian physics. Much of
the summary below is adopted from different
sources in Wikepedia and from Rasmussen 2010,
from where additional information is available.
Aristotle was born in Stageira in 384 BC, about 55
km east of the modern-day city Thessalonika. His
father Nicomachus was the personal physician to
King Amyntas of Macedon. Aristotle was trainedand educated as a member of the aristocracy. At
about the age of eighteen, he went to Athens tocontinue his education at Plato's Academy. Aristotle
remained at the academy for nearly twenty years
before quitting Athens in 348/47 BC, and travelingto Asia Minor, where he studied botany andzoology. In 343 BC Aristotle was invited by Philip
II of Macedon to become the tutor to his son
Alexander the Great. Aristotle was appointed as thehead of the royal academy of Macedon and gave
lessons not only to Alexander, but also to two otherfuture kings: Ptolemy and Cassander. By 335 BC he
had returned to Athens, establishing his own school
there known as the Lyceum, where he conductedcourses at for the next twelve years. It is during thisperiod in Athens from 335 to 323 BC when
Aristotle is believed to have composed many of his
works.
Aristotle studied almost every subject possible atthe time, and made significant contributions to mostof them. In physical science, Aristotle studied
anatomy, astronomy, embryology, geography,
geology, meteorology, physics and zoology. In
philosophy, he wrote on aesthetics, ethics,
government, metaphysics, politics, economics,
psychology, rhetoric and theology. He also studied
education, foreign customs, literature and poetry.

His combined works constitute a virtualencyclopedia of Greek knowledge. It has beensuggested that Aristotle was probably the lastperson to know everything there was to be known in
his own time. Like his teacher Plato, Aristotle's
philosophy was aiming at the universal. Aristotle,
however, found the universal in particular things,
which he called the essence of things. Aristotle's
method is both inductive and deductive, while
Plato's is essentially deductive from a priori
principles.
In 350 BC Aristotle wrote a treatise entitled'Meteorologica', which probably is the first attempt
ever to make a comprehensive about the earthsciences, including meteorology. 'Meteorologica'consists of four books, including early accounts ofwater evaporation, weather phenomena, andearthquakes, and was considered a benchmark
publication for more than 2000 years. Interestingenough, Aristotle expected clouds to consist ofwater. In chapter (part) nine in his first book, hedirectly states that 'air condensing into water iscloud'.

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Clouds and rainIn 'Meteorologica' Aristotle presents a number ofinteresting interpretations concerning different
phenomena related to the Earth, atmosphere, clouds
weather, climate and climate change effects:
Earth, Sun and atmosphere









The earth is surrounded by water, just asthat is by the sphere of air, and that again
by the sphere called that of fire.
...four bodies are fire, air, water, earth.
Fire occupies the highest place among
them all, earth the lowest, and two elements
correspond to these in their relation to one
another, air being nearest to fire, water toearth.
...the motion of these latter bodies [of four]
being of two kinds: either from the centre orto the centre.
Fire, air, water, earth, we assert, originate
from one another, and each of them exists
potentially in each, as all things do that canbe resolved into a common and ultimate
substrate.
The efficient and chief and first cause is thecircle in which the sun moves. For the sun
as it approaches or recedes, obviously
causes dissipation and condensation andso gives rise to generation and destruction.



Now the earth remains but the moisturesurrounding it is made to evaporate by the
sun's rays and the other heat from above,and rises. But when the heat which was
raising it leaves it, in part dispersing to thehigher region, in part quenched throughrising so far into the upper air, then thevapour cools because its heat is gone andbecause the place is cold, and condenses
again and turns from air into water. And
after the water has formed it falls down
again to the earth.
Since water is generated from air, and air
from water, why are clouds not formed in
the upper air? They ought to form there themore, the further from the earth and thecolder that region is. For it is neither
appreciably near to the heat of the stars,
nor to the rays reflected from the earth. It isthese that dissolve any formation by theirheat and so prevent clouds from forming
near the earth. For clouds gather at the
point where the reflected rays disperse in
the infinity of space and are lost. To explain
this we must suppose either that it is not all
air which water is generated, or, if it isproduced from all air alike, that what
immediately surrounds the earth is not mere
air, but a sort of vapour, and that its
vaporous nature is the reason why it
condenses back to water again.
However, it may well be that the formationof clouds in that upper region is also
prevented by the circular motion. For the airround the earth is necessarily all of it inmotion, except that which is cut off inside
the circumference which makes the earth acomplete sphere. In the case of winds it isactually observable that they originate inmarshy districts of the earth; and they do
not seem to blow above the level of thehighest mountains. It is the revolution of theheaven which carries the air with it andcauses its circular motion, fire being
continuous with the upper element and air
with fire. Thus its motion is a second reason
why that air is not condensed into water.
The exhalation of water is vapour: aircondensing into water is cloud. Mist is what
is left over when a cloud condenses into
water, and is therefore rather a sign of fineweather than of rain; for mist might becalled a barren cloud. So we get a circular
process that follows the course of the sun.
For according as the sun moves to this sideor that, the moisture in this process rises orfalls. We must think of it as a river flowing
up and down in a circle and made up partlyof air, partly of water. When the sun is near,
the stream of vapour flows upwards; when it
recedes, the stream of water flows down:
and the order of sequence, at all events, inthis process always remains the same. So if'Oceanus' had some secret meaning inearly writers, perhaps they may have meant
this river that flows in a circle about theearth.
So the moisture is always raised by theheat and descends to the earth again when
it gets cold. These processes and, in somecases, their varieties are distinguished by
special names. When the water falls insmall drops it is called a drizzle; when thedrops are larger it is rain.

Water vapour, dew and hoar-frost






25

Some of the vapour that is formed by day
does not rise high because the ratio of thefire that is raising it to the water that is being
raised is small
Both dew and hoar-frost are found when thesky is clear and there is no wind. For thevapour could not be raised unless the sky
were clear, and if a wind were blowing it
could not condense.
...hoar-frost is not found on mountains
contributes to prove that these phenomena
occur because the vapour does not risehigh. One reason for this is that it rises fromhollow and watery places, so that the heatthat is raising it, bearing as it were too
heavy a burden cannot lift it to a greatheight but soon lets it fall again.

WeatherWhen there is a great quantity of exhalationand it is rare and is squeezed out in thecloud itself we get a thunderbolt.
So the whirlwind originates in the failure of
an incipient hurricane to escape from its
cloud: it is due to the resistance which
generates the eddy, and it consists in the
spiral which descends to the earth anddrags with it the cloud which it cannot shakeoff. It moves things by its wind in the
direction in which it is blowing in a straight
line, and whirls round by its circular motion
and forcibly snatches up whatever it meets.

Climate change effects:


So it is clear, since there will be no end totime and the world is eternal, that neither
the Tanais nor the Nile has always been
flowing, but that the region whence theyflow was once dry: for their effect may be
fulfilled, but time cannot. And this will beequally true of all other rivers. But if rivers
come into existence and perish and thesame parts of the earth were not always
moist, the sea must needs change
correspondingly. And if the sea is always
advancing in one place and receding inanother it is clear that the same parts of thewhole earth are not always either sea orland, but that all this changes in course oftime.

Aristotle's writings were never to influence directlyon practical meteorology. For many centuries
people relied instead on a number of weather rulesof thumb, sometimes blended with the assumptionof a certain degree of divine interference. One ofAristotle's students, Theophrastus (371-287 BC)
succeeded him as a director of the Lyceum inAthens. He took over the philosophy of Aristotle inparts reshaping, commenting, and developing it inan original way. His thinking leads to empirism bymeans of observation, collection, and classification.
Theophrastus was years the director of the Lyceum
around 35 years and he was a teacher of up to 2000
students. Today he is often considered the "father ofbotany". In addition, he probably was the first in
Europe to discover Sunspots (although observed
also independently and much earlier in China).
However, he also continued Aristotle's work on
meteorology, formulating about 80 weather rules,
based entirely on observations. This indicates that
empirical meteorology already at this time hadreached an advanced stage in Greek science(Rasmussen 2010).
Later, much of the scientific knowledge acquired
and formulated by Aristotle and his students was
sadly ignored and forgotten in Europe, and it was
not before 1000-1100 AD that it was rediscoveredby European scientist, after surviving among
Arabian scientists. By this, with a delay of at least
1300 years, the theories and explanations set forth
by Aristotle were to gain huge impact on the later
European scientific development.

References:
Rasmussen, E.A. 2010. Vejret gennem 5000 år (Weather through 5000 years). Meteorologiens historie. Aarhus
Universitetsforlag, Århus, Denmark, 367 pp, ISBN 978 87 7934 300 9.

*****

All the above diagrams with supplementary information, including links to data sources and previous
issues of this newsletter, are available on www.climate4you.com

Yours sincerely, Ole Humlum (Ole.Humlum@geo.uio.no)
21 November 2011.

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