Symposium

Monash University NATURAL CLIMATE CHANGE

24 May, 2009

The Recent History of Man,

and the Influence of Climate.

Throughout the recorded history of Man there have been times of

• warm climate, with reliable rainfall and prosperity ,

and times of

• cold climate , with erratic rainfall,

and with famine and pestilence.

The great works of Man were built during the periods of

warmth and prosperity. There was a surplus of rural production.

In the periods of colder climate, crops often failed, building

ceased, and there was migration of peoples from the coldest

regions.

Estimated sea surface temperatures last 3000 years : Sargasso Sea sediments.

Warm periods were prosperous

Ancient Egypt.

When the pyramids were being built, was the climate similar to today?

Ancient Greece:

When the Parthenon was built, was the climate similar to today?

Ancient Rome: At the time of the colosseum, was the climate similar to today ?

Rome was a great city, capital of an empire.

The Roman engineers built great aqueducts for

irrigation and water supply to their cities.

This is an aqueduct in Turkey.

The Roman Empire flourished in a warm climate, with reliable rainfall.

The rural prosperity supported large cities, and large armies.

The Roman Empire extended from Jerusalem to the north of England.

The Goths, largely nomadic, extended over the plains of eastern Europe.

In 300 AD the weather in Europe

started to become colder.

The Goths invaded Europe.

Rome fell !

The accumulated learning of the ancient world

was almost totally destroyed.

A few hardy scholars preserved the precious ancient writings.

Our civilisation was almost lost, …

because of natural climate change!

By 500 AD, the Roman Empire was ended.

What caused this dramatic change?

The cold climate of the Dark Ages

continued until about 800 AD.

Then the climate became warmer.

The warm period lasted until about the year 1300.

It is known as the Medieval Warm Period.

It was a time of prosperity and enlightenment in Europe.

Many great cathedrals were built.

Universities were founded.

The Viking explorations and settlements, from 800 to 1000 AD.

Medieval Warm Period.

Prosperity in Europe.

Many great cathedrals were built,

eg.Notre Dame, Wells.

There were vineyards in England.

The vikings discovered and settled

in a verdant land they called

Greenland.

The climate in Europe was warmer

than now!

Notre Dame, Paris.

The Great Cathedrals of Europe.

Wells Cathedral

The Medieval Warm Period from 800 to 1300 was a time of prosperity in Europe.

From 1200 to 1285 AD the Mongols advanced into Eastern Europe, the Middle East,

China, Burma, and India. Was it due to the climate becoming colder?

THE LITTLE ICE AGE of over 500 years.

The climate of Europe was mostly cold and unpredictable from 1315 to 1850.

Crops failed and cattle perished.

Famine followed famine, bringing epidemics . There was fear and distrust.

There was belief that crop failures were a sign of God’s wrath at human sin.

Witchcraft accusations soared.

In France in 1520, fires for the execution of witches blazed in every town.

Inquisitors identified witches. One took credit in burning 900 in 15 years.

In 1563, in Wisensteig in Germany, 63 women were burnt to death as witches.

Today, our environmental sins

have overtaken our spiritual transgressions

as the alleged cause of climate change.

Are we causing climate change?

1346 – 1349 The Plague, called the Black Death:

The total population of Europe before the plague

was about 80 million people.

It is estimated that there were 40-50 million deaths,

almost two-thirds of the population.

A contributing factor would have been the colder climate,

with reduced harvests, making people less resistant.

Many villages were deserted,

and remained so for over three centuries.

The Thames froze in many winters from 1607 to 1814.

Frost fairs were held.

England survived by the growth of industries, and overseas trade .

Europe 1709 : The coldest winter in 500 years.

In January 1709 a deadly cold descended on Europe.

The Baltic Sea froze. Lakes and rivers froze.

The soil froze. Livestock died in the barns.

Trees exploded. Fruit trees died.

Birds died by the millions.

Travellers froze to death on the roads.

In France, more than a million people died.

After the deep cold of 1709

the climate of Europe became milder,

gradually warming to the benign climate of today.

But from time to time,

in the northern hemisphere,

there were occasional winters of intense cold.

Annual Average Number of Sunspots from 1750

0

20

40

60

80

100

120

140

160

180

200

1750 1800 1850 1900 1950 2000

Year

Av

era

ge

An

nu

al N

um

be

r o

f s

un

sp

ots

Lance Endersbee

Linear trend

1812 early Nov.

Napoleon retreats

from Moscow.

1812 late Nov.

Temperatures down

to – 30 C.

Loss of 500,000 men.

Niagara Falls

froze in

in

1848

1902

1908, 1909

1911, 1912.

Exploring the

frozen

Niagara Falls :

1909.

Niagara Falls:

1911

Skating at Kinderdijk, Jan 2009

Is Europe becoming colder again?

What has been the cause

of these changes in the natural climate ?

Sometimes the changes last for one season,

sometimes decades, sometimes centuries.

Are they due to variations in the energy flow to

the earth from the sun and the cosmos?

What are the natural driving forces ?

Does the electromagnetic dynamo of the sun,

and cosmic electromagnetic radiation,

drive the electromagnetic motor of the earth?

If there is a varying energy input to the earth,

does it influence the speed of rotation of the earth?

Changes in the rate of rotation of the earth.

In each day there are 24 hours,

of 60 minutes,

of 60 seconds,

totalling 86,400 seconds.

The difference between

the astronomically determined duration of the day

and 86400 SI seconds

is called the length of day (LOD).

It has been measured since 1623.

The oceans cover over 75 % of the surface of the earth.

The measurement of the temperature of

the surface of the oceans

is now reliable and extensive.

Is there a relationship

between global average sea surface temperatures

and the speed of rotation of the earth,

as measured by the Length of Day?

Fin

Using a 21 year moving average of the data,

there is a direct relationship between ,

• the speed of rotation of the earth, (length of day) ,

and,

• global average sea surface temperatures.

Can that relationship be changed by Man ?