The British meteorologist, H. H. Lamb (1913 1997), was one of the first to suggest that climate could change within human experience, contrary to the view of his contemporaries that climate could be considered constant for all practical purposes. He became known for his prediction of the gradual global cooling and a coming ice age.
He early developed theories about the medieval warm period and the little ice age based on "data from the realms of botany, historical documentary research and meteorology". He encouraged his students to be aware of signs and evidence of climate change in the landscape, history, old photographs and the like.
He lived long enough to experience the theory that only the human emission of greenhouse gases can cause climate change, but he maintained a skeptical attitude to this new climate theory, believing that there was "too much reluctance to consider the full range of other, natural, causes of change." Right to the end of his days, he was promoting his "different view".
1. Holocene - the cradle of civilizations
If you want to know how the climate was like in the Holocene, you just have to put on some outerwear and go out into nature and look around. The Holocene denotes the present, since the end of the Weichel Ice Age.
The interglacial Holocene has supported the development and growth of human civilizations; it has been the cradle of civilizations, not to say their womb.
It started about 11,700 years before present with a sudden warming from the cold period called the Younger Dryas. In only ten years, the temperature in Greenland rose by as much as 8℃, which corresponds to Northern Europe's climate being replaced by a Mediterranean climate. It is not known what caused this rapid rise in temperature.
The Cenozoic is the period of mammals, which succeeded the Mesozoic, which was the period of the dinosaurs. The Paleogene and Neogene, which cover the period formerly called the Tertiary, are the part of the Cenozoic where there were no humans, and the Quaternary denotes the part of the Cenozoic where humans existed. Quaternary consists of Pleistocene and Holocene. The Pleistocene is the period that we use to call the Ice Age. Holocene denotes the present, which is basically a Pleistocene interglacial period. The Holocene is represented by the thin red line on the far left. The climate of the Holocene is the subject of this article. Own work.
During the following thousands of years, the temperature increased further, so that the climate became several degrees warmer than today. Around 8,000 years before the present, in the hunter stone age, the warmest time of the entire Holocene occurred. This ushered in the period of warmth known as the Holocene Optimum, which lasted largely until about 4,500 BC, after which temperatures continued to fall through the Bronze, Iron, and Historic time until reaching a low point during the Little Ice Age in 1600- 1700s. Within the last few hundred years, the temperature has risen again, but not to such heights as in the hunter stone age.
This graph is taken from
Wikipedia. It shows eight different reconstructions of Holocene temperature. The thick black line is an average of these. Time progresses from left to right.
On this curve, the Stone Age is shown only about one degree warmer than today, but most sources mention that the Scandinavian Stone Age was about 2-3℃ warmer than today. They do not have to be mutually exclusive statements, because the curve reconstructs the entire Earth's temperature, and in the higher latitudes the temperature variations have been greater than around the equator.
Some reconstructions show a vertical dramatic increase in temperature around the year 2000, but this does not seem reasonable to the author, since this kind of curve cannot possibly show the temperature in specific years, it must necessarily be smoothed by some kind of rolling average, perhaps over a hundred years, and then a high temperature in a single year, for example 2004, will be much less visible.
The trend seems to be that the Holocene's highest temperature was reached in the Hunter Stone Age around 8,000 years before the present, after which the temperature has generally been steadily falling, but superimposed by many cold and warm periods, including the modern warm period.
Overall, however, an amazingly stable climate prevailed in the Holocene, and the cooling down through the period has been limited to a few degrees.
The general decreasing temperature since 8,000 years before present has been superimposed by several cold and warm periods. Thus, one talks about five to seven cold periods in the Holocene, including the Little Ice Age and several warm periods, including the Minoan, the Roman, Medieval and Modern warm periods.
Temperature variations in the Holocene compared to the preceding Weichel ice age based on analysis of Greenland ice cores. The vertical scale on the left is the temperature of the ice surface, and the horizontal scale is years before present. Time progresses from left to right. It can be seen that the climate in the Holocene has really been very stable and the temperature has only varied by a few degrees. The most dramatic event so far has been the 8,200 cold period and the subsequent Holocene maximum in the Stone Age. In contrast, the climate in the previous ice age was not nearly as stable. The temperature often varied more than 20℃ within a few hundred years or perhaps less. Graph Science Direct.
However, the cold and warm periods of the Holocene represent only small temperature fluctuations compared to both the ice ages themselves and the other interglacials.
This unique climatic stability made the development of arable farming possible, it created the basis for the development of civilizations and ultimately made possible the industrial revolution and thus the entire modern world with its technology and multitudes of people. Had we not had a window of just over 10,000 years of stable climate with only small temperature fluctuations, civilizations would not have been nearly as developed, if existing at all, and the Earth's population would have been only a fraction of the current one.
Temperature variations in the Holocene compared to the preceding interglacials. The vertical scale is the temperature of the ice surface, and the horizontal scale is thousands of years before the present. It can be seen that the Holocene temperature curve has a different shape than the previous interglacials. The Holocene has an almost flat top, which represents a fairly stable climate over ten thousand years, while the preceding interglacials are generally pointed, that is, the temperature rose to a maximum and then fell again, perhaps after only a few hundred years. Only the Holocene could offer a stable climate for a long time, where agriculture and civilizations could develop.
Also note the characteristic shape of almost all heat periods. The warmth comes suddenly, perhaps over a few decades, and then slowly fades. This is also the case in the Holocene, although the temperature has fallen much more slowly than in the other interglacials and warm periods. Furthermore, the preceding interglacials were generally warmer than the Holocene. Graph Utah Geological Survey.
Many believe that the decreasing Milankovitch insolation explains the general cooling trend during the Holocene. The Milankovitch insolation is the theoretical insolation at 65 degrees north latitude in June. Its variation in the Holocene is mainly due to changes in the tilt of the axis, so that the Northern Hemisphere initially received a large June insolation, facing more directly towards the Sun in summer, while today the axis is more vertical, and therefore the Northern Hemisphere does not receive as much solar radiation in summer.
Temperature and Milankovitch insolation during the Holocene.
The upper reddish curve represents the temperature in degrees Celsius on the ice surface in Greenland. The curve is generally falling through the Holocene but is superimposed by many cold and warm periods. Many operate with six cold periods, of which the two best known are the 8,200 cold period and the Little Ice Age. The best known warm periods are the Minoan, Roman and Medieval warm periods.
The Norwegian Axel Blytt and the Swede Rutger Sernander developed in the 19th century the Blytt-Sernander period division of the Holocene climate based on studies of Danish peat bogs. It includes the Preboreal, Boreal, Atlantic, Subboreal and Subatlantic periods, which are shown at the bottom of the figure. Preboreal is also referred to as the birch-pine period. There are many different opinions about when the individual Blytt-Sernander periods start and end.
Today, some believe that this division is outdated and prefer other divisions, which include the Holocene Climatic Optimum, Postglacial and Neoglacial, as shown above with colors.
The yellow-green graph shown below the temperature curve is the theoretical Milankovitch insolation in the Holocene in Watts per m2. The Milankovitch insolation is the solar radiation at 65 degrees north latitude in the month of June. It can be seen that the insolation maximum occurred around 10,000 years before the present with around 470 w/m2, and since then the insolation has been steadily decreasing to today's barely 430 W/m2. Graph unknown origin.
In the first beginning of the Holocene, Northern Europe was covered with an open and light birch forest mixed with aspen, willow, rowan and pine. The increasingly mild climate caused the average summer temperature to rise to 18-20℃, while the winter temperature was just below freezing. The composition of the forest's trees changed; pine pushed back birch while hazel, elm, oak, ash, alder, spruce and linden immigrated.
2. 8.200 Cold Period
Around 8,200 years ago, a severe cooling occurred in the Northern Hemisphere. It has been explained by a large supply of cold meltwater from glaciers in the Hudson Bay area. Data from Disko Bay show that there was also a large production of meltwater here. Samples taken from the seabed at Svalbard indicate that here the arctic water masses penetrated further south as early as 8,800 years ago.
From HOCLAT - A web based Holocene Climate Atlas. Reconstructed air temperature in summer from pollen analysis from sediments from the bottom of a Swedish lake at 58.55 degrees north latitude and 13.67 degrees east longitude, which is a small Swedish lake between Vänern and Vättern. That has been treated so that climate variations become relative, in relation to the general climate in the period.
The raw original data is the very thin line in the figure at the top. They have been smoothed by some form of mathematical rolling average over 500 years; it's the blue line. Furthermore, the original data has also been mathematically smoothed over 3,000 years. That's the red line. The figure below shows how much the blue line deviates from the red line, which is an expression of the relative climate changes. The blue areas thus show how much the temperature in cold periods deviates from the more average temperature in this age, and the red areas show how much the temperature in warm periods exceeds the more average temperature in this age.
It can be seen that in the early Holocene the relative temperature changes were greater than in the present. If the Stone Age people had lived long enough, they would subjectively have experienced more dramatic temperature changes than modern people.
The severe 8,200 cold period was the relatively most dramatic climate upheaval. It has been an nasty surprise for the Stone Age hunters.
By the way, the cold spells seem to come at regular intervals. The cold period 6,100 years before the present occurred at the transition from the Mesolithic to the Mesolithic. The Cold Period 3,500 was at the beginning of the Bronze Age. The minor cold period around 1800 occurred a few hundred years after the birth of Christ, perhaps at the time when the Goths left the island of Skanza (Scandinavia). The Little Ice Age seems to be coming a bit early. Graph HOCLAT.
Many explain the 8,200 cold period as the result of a large discharge of cold meltwater into the Atlantic Ocean from Lake Agassiz at the edge of the Laurentide ice sheet in North America.
It may seem paradoxical that warmer weather in the Arctic, which was the cause of the melting of ice caps and the melting of sea ice and thus the production of cold fresh water, is the cause of a colder climate in Northern Europe and probably also in North America. This is explained by the fact that the large amounts of cold fresh water, which is lighter than salt water, disturbed the ocean currents, especially the Gulf Stream, which caused colder weather along the coasts of the North Atlantic. Many believe that such a meltwater mechanism was also the cause of the Younger Dryas cold period.
Analysis of oxygen isotopes in stalactites from Costa Rica shows a dry period around 8,200 BC. From "Tropical response to the 8200 yr B.P. cold event --" Graf Matthew S. Lachniet and others.
Even more incomprehensible is that a team of American geologists from the University of Buffalo and other universities has found that during the cold period the glaciers on Baffin Island grew. One can only conclude that if meltwater was produced at the same time, the precipitation must have been even very large in these regions.(Uriarte)
Analyzes of oxygen isotopes in stalactites from caves in Costa Rica have shown that there was a dry period here for about 8,200 years before the present, caused by a weaker monsoon and reduced rainfall in Central America. This calls into question the meltwater-Gulf Stream theory, because the climate in Costa Rica is not dependent on a warm Gulf Stream, since the country is located in the area near the equator, which supplies the heat to the Gulf Stream.
The cold period, on the other hand, cannot be detected in the southern hemisphere, neither in drill samples from the Antarctic ice sheet, glaciers in Bolivia or samples taken from the seabed off the mouth of the Murray River in Australia. This indicates that the cold period may have really been a North Atlantic phenomenon, perhaps created by variations in ocean currents.
But after a time the ocean currents in the North Atlantic returned to their old bed, if they were the cause, and about 8,000 years before the present, the warmest period of the Holocene ever began.
In sediments at the bottom of Lakes Huelmo and Mascardi in the Andes Mountains in Chile and Argentina, respectively, evidence of a cold period in the southern hemisphere has been found, which lasted 800 years and occurred between 11,400 and 10,200 years before the present.
3. The Holocene Climatic Optimum
The parasitic plant mistletoe on a willow tree. During the Holocene Optimum, the parasitic plant mistletoe was widespread in southern Scandinavia. During the Little Ice Age, it only grew further south, in Southern England, Central and Southern Europe. But in recent times it has again been found in many places in Denmark. Photo Dominic Eckersley.
The warmest time in the entire Holocene occurred in the hunter stone age around 8,000 years before present. It is called the Holocene Optimum. This warm climate lasted largely for 3,500 years until 4,500 years before the present, when it was during the Neolithic period in Northern Europe.
It is assumed that the average temperature was 2-3℃ higher than today's. This is supported by the fact that plants such as mistletoe and the subtropical water plant hornwort became widespread in Denmark. Linden, elm, fir and oak became the most common trees in Northern Europe's dense forests, which closed the interior of the countries together into a large, intergrown primeval forest.
In Denmark, stone age settlements from the period of the Holocene Climatic Optimum have been investigated and bones of various land and sea animals have been found, including swordfish, sturgeon, sardine and tuna, curled pelican and terrapin, all of which are species that nowadays live in warmer climates.
Fir stumps in the Cairngorm Mountains in Scotland, which testify that it was warmer 4,000 - 4,500 years ago when forest grew on this mountainside. The remnants of the Scottish Ghost Forest exist above the treeline today. Photo Ben Dolphin Walkhighlands.
In the Cairngorm Mountains in central Scotland, you can find stumps of 4,000 - 4,500-year-old pine trees, which at that time grew 650 m above sea level. This height is slightly above the limit for dwarf trees and stunted trees today.
Another evidence of the warmer climate of the past can be found in Dartmoor in southern England, albeit slightly later than the Holocene Optimum. Here, Bronze Age farmers cultivated the land at a height of 450 meters above sea level, which must be compared with the absolute limit for arable farming today, which is 300 meters above sea level.
A team of scientists from the University of Copenhagen has analyzed driftwood and seawalls along the coast of north-east Greenland and thereby uncovered the extent of sea ice during the Holocene Optimum.
Driftwood that ends up on the coast in northeastern Greenland comes from North America and Siberia. It is several years in the making and will therefore only arrive if it is encased in sea ice, since free driftwood will sink to the bottom during such a long journey.
Driftwood on the northern coast of Svalbard. Photo Ann E. Lennert The Nansen Legacy.
By collecting and dating driftwood with the carbon-14 method, the researchers were able to calculate the amount of sea ice in different time periods.
Svend Funder and his colleagues also investigated seawalls along the coast. Nowadays, seawalls are not formed along the coasts of North Greenland, as the sea ice shields the coast all year round. The age of the waals has been determined by the carbon 14 method to date from the Holocene Optimum, during which period the sea off East Greenland must have been ice-free, at least in the summer.
The conclusion was that sea ice reached a minimum between 8,500 and 6,000 years ago, as the limit of year-round sea ice was 1,000 km further north than today, and in summer the sea ice only covered an area half as large as the ice-covered area in summer 2007, when sea ice was at its minimum in recent times.
Some studies indicate that the surface temperature of the World Ocean was up to 5℃ higher than today's surface temperature (Uriarte - Darby, 2001).
Painting by Ivan Shishkin and Konstantin Savitsky. Throughout most of the Holocene, most of Europe, Asia and North America were covered by forest. A large part of the biosphere's carbon was tied up in the trees' wood. Arable farming was introduced and as the trees rotted away or were burned, the atmosphere's carbon content increased in the form of CO2.
The Peary Land ice sheet in northernmost Greenland was drilled in 1977. The ice core contained distinct refrozen meltwater layers all the way down to the bedrock, indicating that it did not contain ice from the Weichel Ice Age. This means that the world's northernmost ice sheet melted away completely during the Holocene Optimum and was only restored when the climate became colder about 4,500 years ago.
As there was less water bound at the poles as ice caps than in our days, the level of the World Ocean was then 3 m above today's water level.
By the end of the period of the Maglemose hunters, around 8,500 BC, the climate in Northern Europe had developed into the so-called Atlantic climate. It was a mild and humid coastal climate with summer temperatures 2-3℃ higher than today.
When the kilometer-thick Scandinavian Ice Shield began to melt, the freshwater lake, The Baltic Ice Lake, was formed. It was a cold sea with drifting icebergs. The surface of the lake was higher than the World Ocean. Some believe that the glacial lake was emptied by an extensive flood disaster around the year 9,600 BC. but most believe it happened gradually.
The landscape of Northern Europe was dominated by icy steppes and regular tundra dotted with a few reindeer hunters.
After the lake had got connection with the World Sea, it became a brackish water sea, as it is today, called the Yoldia Sea. This sea is named after the mussel Yoldia arctica. The Yoldia Sea was connected to the World Sea through a strait that lay where the Swedish lakes and the Gøta River are today.
At the beginning of the Stone Age, the tundra was overgrown by an open and light birch forest mixed with aspen, willow, rowan and pine.
When Scandinavia was freed from the weight of the enormous ice masses, the land rose, the uplift cut off the future Baltic Sea's connection with the World Ocean, and it again became a freshwater lake, which is called Lake Ancylus after the freshwater snail, Ancylus fluviatilis. Lake Ancylus may have drained through central Sweden at the Great Lakes.
In step with the increasingly milder climate, where the summer average temperature rose to 18-20℃, and the winter temperature only just reached below freezing, the composition of the forest's trees also changed; pine pushed back birch, and hazel, elm, oak, ash, alder, spruce and linden became common.
Around 7,000 BC, the climate in Northern Europe was a so-called Atlantic climate. It was a mild and humid coastal climate with summer temperatures 2-3℃ higher than today.
The water level in the World Sea rose, which resulted in the salty sea water penetrating into Lake Ancylus after some time, and the water in the Baltic Sea Basin became salty again. The new sea is called the Littorina sea after the saltwater snail Littorina littorea. It took several hundred years before the salt content reached its maximum.
But due to land uplift, over the past 2,000 years, the Baltic Sea's connections to the World Ocean have become increasingly narrow and shallower, which in turn has turned the sea into the brackish sea we know today as the Baltic Sea. Photo from an older Danish textbook.
In Australia, they have analyzed sediments on the seabed off the mouth of the Murray River and found that from 17,000 to 13,500 years before the present, the Australian climate was wetter than it is today. No indications of dry periods have been found with certainty either in the Younger Dryas or for 8,200 years before the present. Which indicates that these cold periods were phenomena limited to the Northern Hemisphere. (Uriarte)
The partially dried up Black Sea around 5,500 years before present. Photo VictorS KHT.
Samples from bottom sediments in the Australian lakes, Lake Frome and Lake Woods, show that the climate in the early Holocene between 9,500 and 8,000 years ago, and again from 7,000 to 4,200 years ago, was significantly wetter than today. The beginning of modern climatic conditions in Australia with periodic rainy season occurred about 4,000 years ago.
Analyzes of sediments from the Cariaco Basin in Venezuela indicate that the amount of water that was discharged into the basin during the Holocene Optimum was much greater than today, which indicates that the rainfall in the area must have been much greater in the first half of the Holocene than the is today. (Uriarte, Haug).
One of the geographical events in Europe that most reminds us of the Biblical account of the flood is perhaps the sudden flooding of the partially dried up Black Sea, which happened 5,500 years before the present.
For reasons we can only guess, the inland sea had lost connection to the World Ocean and had partially dried up. Its surface was 150 m below that of the World Ocean. The Black Sea receives water from many large and water-rich rivers, just think of the Danube, Dniester, Dneieper and Don. It is difficult to understand that it could have lost more water by evaporation than it received from the rivers. It must be a testimony that it was really very warm during the Holocene Optimum. It is assumed that the temperature during this period was 2-3℃ higher than in the present.
Fragment of the motif The Deluge by Michelangelo from the Sistine Chapel. Jorge Valenzuela Wikipedia.
A marginal rise in World Wea level 5,500 years before present created a small crack in the barrier at the Bosphorus, an insignificant trickle of seawater down the Black Sea basin quickly developed into a huge waterfall of salt water, 200 times bigger than Niagara. It is believed that the seawater gushed into the half-dried Black Sea and caused the level to rise by 15 cm. per day, thereby raising the water level 150 m. up to the level of the World Sea in the course of about three years.
When this flood wave occurred, there was a Neolithic period in Northern Europe, and it had probably been so for a long time in the area around the Black Sea. Oceanographer Robert Ballard has examined the bottom of the Black Sea with the help of an underwater robot and found signs of human habitation.
Many peoples have the story of an original flood wave among their ancient myths. In the Bible's Genesis, God parted the waters and created Heaven and Earth. In the Egyptian creation myth, everything in the beginning was also a chaos of water, and the God Ra separated the waters and created the World. The Bible also has the story of the flood and how Noah and his family survived. In Scandinavian mythology, the gods Odin, Vile and Ve killed the primordial giant Ymer; in the flood wave created by Hrymer's blood, all his children, the Rimturses, drowned, except Bergelmer and his wife, and from them descended the Jats. Even the Australian Aborigines have an original flood wave among their ancient myths.
4. A green Sahara
Rock painting of kneeling giraffe giving birth, Oued In Djerane, Tassili n'Ajjer National Park, Photo: Andras Zboray, FJ Expeditions
For a longer period, roughly corresponding to the Holocene Optimum, northern Africa experienced a time with a considerably wetter and rainier climate than that which now prevails in the region. Many state the period to be from 10,500 to 5,500 before present, but there seems to be uncertainty about the dating.
Where there is now barren, dry desert, was then savannah with extensive grasslands and a few trees. There lived lions, elephants, giraffes and other animals which are now characteristic of southern Africa.
Rock painting with elephants from Wadi Methandous, Messak Settafet in Libya. Photo Libyan Heritage House.
Former professor of African history at the University of London, Roland Oliver, described the landscape as follows: The great mountain ranges Tibesti and Hoggar, which today are bare rock, were then covered by forests of oak and walnut, linden and elm. The lower slopes, together with the smaller mountains, Tassili and Acacus to the north, Ennedi and Air to the south, were covered with olive, juniper and Aleppo pine. Through the grasslands of the valleys rivers were flowing, filled with fish.
Rock paintings across the Sahara testify to a time when the land was greener and home to lions, elephants, giraffes, antelopes, hippos and crocodiles. A picture from Tassili, now a parched desert, shows men standing up in boats sailing on the water. It testifies that there were lakes and rivers in places where today there is not a blade of grass.
Rock painting of hippo cubs from the "great wild fauna period" near Oued Djerat, which is in southern Algeria, far out in the desert. Photo David Coulson and Alec Campbell - Rock Art of the Tassili'n Ajjer, Algeria.
Most of the rock paintings in the Sahara have been found in Algeria, Libya, Morocco and Niger, and to a lesser extent Egypt, Sudan, Tunisia and some Sahel countries. The Air mountains in Niger, the Tassili-n-Ajjer plateau in southeastern Algeria and the Fezzan region in southwestern Libya are particularly rich in ancient rock paintings.
Lake Chad reached a maximum extent of about 400,000 square kilometers, which is larger than the modern Caspian Sea, with a surface level about 30 m higher than in modern times.
Around 3,500 BC the desert spread again over North Africa, and the scattered cattle nomads moved to the Nile Valley, where they began to cultivate the land and where they established the First Dynasty and thus founded the famous Egyptian culture.
In the time of the pharaohs, there were still lions in Egypt. They lived on the border of the desert, where they were known as the guardians of the eastern and western horizons, guardians of the eastern and western descent into the underworld, or the past and the future. The sphinxes possibly represent the pharaoh in the form of a lion with a human head.
Climatic settlements in the eastern Sahara through the main phases of the Holocene. Red dots indicate main settlement areas, white dots indicate more isolated settlements associated with climatic refuges and periodic shifts of pastures. Precipitation zones are shown in shades of green based on best estimates based on geological, archaeological and archaeo-botanical data.
(A) During the Last Ice Age Maximum and the end of the Pleistocene, that is from 22,000 to 10,500 years before the present, the Sahara desert was devoid of any settlement outside the Nile Valley and the desert stretched for 400 km. further south than it does today.
(B) With the sudden appearance of the monsoon rains around 10,500 BC, the hyper-arid desert was replaced by savanna-like landscapes, which were quickly inhabited by prehistoric humans. In the early Holocene Optimum, the southern Sahara and Nile Valley were apparently too humid and dangerous for significant human settlement.
(C) By about 9,000 BC, human settlement had become well established throughout the eastern Sahara, creating a cattle nomadic culture.
(D) Decreasing monsoon rains caused an incipient desiccation of the Egyptian part of the Sahara around the year 7,300 BC. The prehistoric peoples were forced to seek into the Nile Valley, to settle in oases or to migrate to the Sudanese Sahara, where rainfall and surface water were still sufficient. The Sahara's return to true desert conditions around 5,500 BC coincided with the initial stages of Egyptian civilization in the Nile Valley. From Kuper and Kröpelin (2006).
Elephants lived in North Africa long after the desert had returned to the central Sahara.
North African forest elephants were somewhat smaller than both the Indian elephant and the African steppe elephant. Its Latin name is Loxodonta africana pharaoensis, and it became extinct in the second century; they were said to have perished in the Roman arenas.
Left: Sphinx from Luxor. A sphinx is a lion with a human head. Photo Millmore Discover Egypt.
Right: Two lions representing the god Aker. Egypt Museum Aker says that Aker is "the one who looks forward and backward". Aker appears as twin lions, one named Duaj, which means "yesterday", and the other Sefer, meaning "tomorrow". Photo Egypt Museum.
It amazed Cicero that when twenty elephants, an unprecedented number, were attacked by men with spears in the arena in a show given by the great Pompey, all the spectators in the theater became so deeply moved that they began to weep.
The Arabian desert in the Middle East and the Rajastan desert between India and Pakistan also experienced a wet period in the first part of the Holocene. In the dried up lakes of the deserts, spores from plants have been found, which are characteristic of a savannah vegetation.
The Expulsion from the Garden of Paradise painted by Natoire in the year 1740.
Other studies show that at the beginning of the Holocene, Central Asia experienced a wetter climate than today, characterized by summer temperatures that were 2-3.5℃ higher. In China, the rice could be planted almost a whole month earlier than is usually the case today. Bamboo groves could be found three degrees of latitude further north than they are found in modern times. (Uriarte, Chu Ko-chen)
Many peoples have old myths about an original homeland that they left in the distant past. The ancient Doric Greeks immigrated from the north; the Scandinavian peoples remember Asgaard and Midgaard. According to their old myths, the Romans originally came from Troy, and probably the best-known myth of this kind is the Biblical story of the expulsion from the Garden of Paradise. It is quite likely that the factors which forced the peoples to migrate were connected with such climate changes which took place in connection with the end of the Holocene Optimum.
5.Between the Holocene Optimum and the Roman Warm Period
Rainfall in the Rajasthan desert. It can be seen that in the time before the Holocene it was a fairly dry desert. Rainfall peaked around 6,000 years before the present, and while the Harappan culture existed, rainfall was 600 to 800 mm per year. This can be compared with the average annual rainfall in Denmark, which is 745 mm. From H.H. Lamb: Climate, History and the Modern World.
Around 5,500 to 5,000 BC, the Piora Cold Period occurred, named after the Val Piora valley in Switzerland, which was the first place where it was detected using pollen analysis. The more heat-demanding trees such as elm and linden became rarer and never later regained their dominant position in the forest. Indications of this cold period have been found both in Alaska, in the Andes in Colombia and in the mountains of Kenya (Lamb).
In the Indus Valley, where today Rajasthan's dry Thar Desert spreads, the cities of Harappa and Mohenjodaro flourished between 4,600 and 3,900 years before the present. At its height, their civilization covered an area larger than the Nile Valley and Mesopotamia combined. The inhabitants cultivated wheat, barley, melons, dates and perhaps cotton. Elephants, rhinoceroses and water buffalo lived on the savannah and along now-dried rivers. The annual rainfall is estimated to have been between 400 and 800 mm.
The cities of Harappa and Mohenjodaro existed in the Indus Valley 4,000 years ago. Photo Ancient Indian History.
In the Arabian desert, signs of human habitation have also been found from around 5,000 years before the present.
The Minoan culture takes its name from the Bronze Age civilization of Crete from about 3,100 to about 1,100 BC. It was one of Europe's first major civilizations.
Not much is known about the Minoan Warm Period apart from what can be read from cores from boreholes in the ice sheet. That the climate was really warmer then can be derived from the fact that during the Minoan warm period, which occurred in the Danish Bronze Age, millet was grown in southern Scandinavia. Millet is grown today in tropical and subtropical areas, it is an important crop in Asia, Africa and in the southern United States. The annual average temperature in Mississippi and Alabama is about 10℃, which should be compared with today's annual average temperature in Denmark, which is 8℃. So perhaps the mid-Bronze Age climate was around 2℃ warmer than in today's Scandinavia.
During the Minoan warm period, millet was cultivated in the Bronze Age in southern Scandinavia. Photo Gerd Eichmann Wikimedia Commons.
As you know, Rome was founded by Romulus and Remus in 753 BC. The Roman historian Livy tells that in the city's early history there were a few severe winters, when there was ice on the Tiber and the snow remained for many days. It is said that before the Roman warming period, beech trees grew in the mountains around Rome.
Climate change has always occurred, it is documented in the Bible. In Jeremiah 18.14 of the Old Testament it says: "Does the snow of Lebanon ever vanish from its rocky slopes?
Do its cool waters from distant sources ever stop flowing? Yet my people have forgotten me; they burn incense to worthless idols". It indicates that it really was relatively cool around the Mediterranean when Jeremiah lived around 600 BC. Nowadays there is no eternal snow on the mountains of Lebanon.
Left: The extent of sea ice in the Arctic Ocean in modern times. It can be seen that nowadays it is quite far from Iceland to the sea ice on the Greenlandic east coast north of Scoresbysund. Regardless of whether Pytheas went ashore on the Faroe Islands, Iceland or western Norway, just one day's sailing to the frozen sea means that the sea ice in the summer had a significantly greater extent than in the present day. Photo National Snow and Ice Data Copenhagen.
Right: Pythea's travels. From Histoire des Mar es: Pyth as le massaliote
Around 310 - 300 BC Greek explorer Pytheas traveled from Massalia (Marseille) to the shores of Western Europe. He came to Scotland and the Hebrides, where he saw waves that were "80 cubits high" (the cubit is an ancient unit of length of 45.72 cm). He sailed to the island of Thule, which lay 6 days and 6 nights' sailing north of Berrice, supposed to be the Shetland Islands. There is uncertainty as to whether Pytheas' Thule is the Faroe Islands, Iceland or Western Norway.
A statue of Pytheas in front of the stock exchange in Marseille. Photo Wikimedia Commons.
The distance between Shetland and the Faroe Islands is 150 nautical miles, and the distance between Shetland and Iceland is about 380 nautical miles. On the trip to the Faroe Islands, he should thus have maintained a speed of 1 knot, which sounds quite manageable, even for that time. If Thule was Iceland, he should have maintained a speed of 2.6 knots, which was also not impossible with a good wind.
He describes Thule as an island six days' sail north of Shetland, near the frozen sea. There is no night at midsummer, he says, which indicates that it is the Arctic Circle and that he visited the island in the summer. The frozen sea is a day's sailing north of the island, he says, which also suggests that it is Iceland rather than the Faroe Islands.
However, in modern times sea ice is found closest to Iceland in the summer north of Scorebysund on the east coast of Greenland. From Iceland to the north of Scoresbysund is a good 350 nautical miles. Pytheas sailed perhaps 2.6 knots, so it would have taken him just under 6 days and nights to reach the frozen sea, with the modern extent of the sea ice.
But since he wrote that the sea ice was only one day's sail north from Thule, we can conclude that the sea ice in the Arctic Ocean in the summer was far more widespread in his time, 300 BC, than it is today.
A reconstruction of Pythea's ship. A ship of this type cannot have sailed the North Atlantic in winter. In fact, well into the Viking Age, people did not sail on the North Atlantic in winter. It emphasizes that he visited Thule in the summer. Photo tapantarei.gr
Pytheas mentions that the island was inhabited. People lived on millet and other herbs, and on fruit and roots, and where there was grain and honey, they got their drink from it. The country was rainy and lacked sunshine, he wrote. This leads many to believe that he actually landed in Norway. But if the sea ice was only a day's sail from there, that just indicates an even greater spread of sea ice.
6. The Roman Warm Period
Fresco in Pompeii depicting a Roman orgy. As can be seen from their light clothing, it must have been quite warm. Photo Casa dei Casti Amanti - La Repubblica.
The Roman Warm Period started rather suddenly around 250 BC. and ended around 400 AD. The ancient Greeks and Romans lived in a rather pleasant climate, which you can also see from the airy robes that the ancient statues are often dressed in.
Some studies in a bog in Penido Vello in Spain have shown that in the Roman period it was about 2-2.5℃ warmer than in modern times. (Uriarte)
The Roman Warm Period is abundantly documented by countless analyzes of sediments, tree rings, pollen and ice cores, especially from the Northern Hemisphere. Studies from China, North America, Venezuela, South Africa, Iceland, Greenland and the Sargasso Sea have all proven the Roman Warm Period. Furthermore, it is documented by ancient authors and historical events.
The Roman Columella wrote in the first century after Christ in "De Re Rustica "(book 1), citing the "reliable author Saserna": "Areas (in Italy), which previously due to the regular severity of the weather could not provide any protection for vine plants or olive trees planted there, now that the former cold have subsided produce olives and wine in the greatest abundance."
Coins from Carthage with elephant motifs. Note the first coin from the left, here the man is quite large compared to the elephant, indicating that these were really relatively small elephants. Photo British Museum, Coin archives, acsearch.info.
Hannibal brought an entire army, equipped with 37 war elephants, over the Alps in 218 BC. - in the winter
The ancient writer Pausanias wrote in the second century about the use of war elephants: "For although the use of ivory in arts and crafts has evidently been known from ancient times to all men, no one had seen the actual animals until the Macedonians invaded in Asia, except the Indians themselves, the Libyans, and their neighbors." It sounds like he believes that elephants rightly belong in both India and Libya.
Roman bridges in Syria. The rivers they crossed have long since dried up.
Top left: The ruins of a Roman bridge between the villages of Ayyash and Ain Abu Jima in the northwestern part of Jebel Bishri on the Euphrates River. Photo: Minna Lönnqvist. The Finnish Project in Syria.
Top right: Roman bridge at Uthma in Syria. Photo: arminhermann.
Middle left: The ancient Roman bridge in Mhardeh in Syria. Photo Bernard Gagnon Wikipedia.
Center right: The Roman Gemarrin Bridge crossing Wadi Zeidi near the ancient city of Bostra. Photo tripbucket.
Bottom left: The Roman bridge Ain Diwar at Malikiyeh in Syria near the Turkish border. Photo unknown origin.
Bottom right: Roman bridge spanning the Sabun Suyu, which was a tributary of Afrin in Syria. Photo Sonia Halliday.
It seems unlikely that Hannibal would have imported his 37 war elephants all the way from India to his native Spain. Therefore, most people assume that these were African elephants.
The common African steppe elephant is difficult to tame, and therefore it was probably a now extinct species of elephant called the North African forest elephant, which was slightly smaller than both the Indian elephant and the common African steppe elephant.
During the culmination of the Roman Warm Period, olive trees grew in the Rhine Valley of Germany. Citrus trees and grapes were grown in England as far north as Hadrian's Wall near Newcastle. Olive presses have been found in Sagalassos on the Anatolian highlands in present-day Turkey, an area where today it is too cold to grow olives.
Strabo wrote that around 120 - 114 BC a series of storms occurred in the North Sea, which caused the so-called Cimbrian flood wave, which flooded large areas along the coast of Germania and thereby caused the migration of the Cimbrians and the Teutons.
The ruined city of Petra in the Jordanian desert. It was supplied with water from a constructed canal. We must assume that some time in the past, when the city was laid out, there was a supply of water on site. As the climate became drier, a canal was built for water supply, but eventually the inhabitants gave up. It is known that during the time of the Crusades in the 12th century, Petra was still inhabited. King Baldwin I of Jerusalem stayed for a time in the city. Photo Vacaywork
North Africa was Rome's granary, which may be hard to imagine today. But it was considerably more green and fertile than in the present day. The city of Petra in Jordan thrived between 300 BC and 100 AD, today it is abandoned and lies far out in the Jordanian desert.
During the Roman warm period, a more humid climate prevailed in North Africa and the Middle East than today. In Alexandria, Claudius Ptolemaeus in 120 AD. wrote a weather diary. It shows a remarkable difference compared to the present climate of this place. It rained every month except August, there was thunder in all the summer months as well as in some other months, and very hot days were most common in July and August.
Ptolemaeus of Alexandria also wrote about four rivers in Arabia and about trade routes which had been in use earlier but had already become impassable in his time. In the Middle East there are still ruins of many Roman bridges built over rivers, which have now dried up.
Around the year 400 AD the Roman Symmachus complained in his letters of the duty which he had to pay for some bears which he had imported from North Africa for use in the circus performance which his son was obliged to give in connection with his appointment as senator. The crocodiles that he had managed to find refused to eat, and he was worried that the poor animals would starve to death before they could play their part in his son's circus.
Location of vineyards is also a good indicator of temperature.
The continued spread of vineyards to the north can be deduced from a decree of Emperor Domitian which prohibits the cultivation of wine in the Empire's western and northern provinces beyond the Alps. The decree was 280 AD revoked by Probus, who allowed the Romans to introduce vineyard into Germany and England.
The Roman Warm Period ended around 350 - 400 AD.
7. The cold period of the Migration Period
Vandals, Swabians and Alans cross the frozen Rhine in 406 AD. Painting by unknown artist.
It is often said that the Vandals crossed the frozen Rhine on New Year's Eve 406 AD, thus ushering in the Migration Period and heralding the fall of the Western Roman Empire. But we must recognize that the historical sources say nothing about the Rhine being frozen. They simply say that the Vandals crossed the Rhine. Perhaps it is Gibbons, who has rationalized that the river must have been frozen.
But much indicates that it was actually very cold around 400 AD.
Many, including Lamb, believe that widespread drought in central Eurasia triggered the migrations towards both China and the Roman Empire from about 300 AD. to 500 AD.
Density of annual rings in larch trees at Zermatt in the Alps. Time progresses from left to right. The vertical red line marks the year 400 AD. From "Climate History and the Modern World" by H.H. Lamb.
H. H. Lamb wrote in his "Climate, History and the Modern World": "For centuries in Roman times from about 150 BC to 300 AD or some few decades later, camel caravans used the Great Silk Road through Asia for trading in luxury goods from China. But from the fourth century AD, which we know from changes in water level in the Caspian Sea and study of irregularities in rivers, lakes and abandoned cities in Sinkiang and Central Asia, drought developed in such an extent that it stopped the traffic on this route. Other severe stages of this drought occurred between 300 AD and 800 AD, and especially around these dates, as it can be seen from old shores lines and old port structures that indicate a very low sea surface level in the Caspian Sea around these times." (page 159).
Already well over 300 AD China had problems with refugees from the steppe. The "Five Hu" people from the north, Xiong Nu, Xianbei, Di, Qiang and Jie sought refuge in the empire behind the Great Wall. When the mandarins ordered them to return to their homeland, they responded by force of arms and established their own migration states. This ushered in the period in Chinese history called "The Sixteen Kingdoms".
The Scandinavian legend of the Fimbul Winter. Drawing by J.C. Dollman.
The drought on the eastern steppe also drove many peoples towards the Roman Empire. From around 400 AD Visigoths, Ostrogoths, Vandals, Alans, Swabians, Huns, Gepids, Angles, Saxons, Franks, Jutes, Alemanni, Burgundians and Lombards invaded. Later Avars, Magyars, Arabs, Vikings and Slaws attacked. The political division of modern Europe is, in the main, a result of all these peoples fighting each other.
In Constantinople the historian Procopius recorded of 536 AD, in his report on the Vandal war: "during this year a most dread portent took place. For the sun gave forth its light without brightness - and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear. From the moment the phenomenon showed up, humans all time were affected by war, famine and other deadly things." His fellow byzantian Lydus wrote: "The sun became weak - almost a full year - so that the fruits died without harvest."
Changes in upper tree line in two areas in the White Mountains of California and the Alps of Switzerland and Austria. It shows that, broadly speaking, the tree line, and thus the temperature, has been falling for at least 3,000 years. The vertical red line marks 400 AD. From "Climate History and the Modern World" by H.H. Lamb.
Michael, The Patriarch of Antioch in Syria (1126 - 1199 AD) wrote about the year 536 AD: "The sun became dark and the eclipse lasted for 18 months".
The Irish Annals of Ulster recorded: "A scarcity of bread in the year 536 AD" and the Annals of Inisfallen wrote "A scarcity of bread in the years 536 - 539 AD." In China, it was reported that the snow in these years fell in August.
Gregory of Tours wrote in the "History of the Franks" (Book 3:37) from the year 539 - 594 AD: "In this year the winter was terrible and more rigorous than usual, so that the rivers were kept in the iron grip of the frost and made into a road for the people like it was dry land. Birds, too, were affected by cold and hunger, and were captured by hand without using the snare, when the snow was deep."
Chinese cave painting from the Mogave Caves at Dun Huang from the Northern Wei period (386-535 AD) - Some tough men - were they kings? Photo Chinese internet.
This hard winter in the Loire Valley has been dated by Gregory as the year when Theodobert died. This happened 37 years after the death of Clovis, who was king of the Franks in the years 465-511 AD. The Year of the harsh winter is then 548 AD.
This suggests that the severe winters in Europe were from the year 536 AD to at least to 548 AD.
In Jæren in Norway around the year 500, large areas were abandoned as agricultural land, which testifies to a colder and harsher climate. Studies of peat bogs in Jutland show traces of flying sand from around the same time (Lamb).
In the battle Ragnarok, Thor meets the Midgard Worm and Odin rides against the Fenriswolf.
The Scandinavian people tell of the Fimbul winter, which will herald the Ragnarok Battle, which marks the end of the world.
In the first part of Snorre's Edda, Gylfaginning, it is written: Then Gangleri said: "What tidings are there to report about Ragnarok? This I have not heard spoken of before".
Har says: "There are great tidings to be told and many. First of all, the winter has come, which is called Fimbulvetr. Then the snow drifts from all directions. The frost is then hard and the winds blow strongly. The sun is of no use. There are three winters after each other and no summer in between; but before that there are other three winters, when there are great battles all over the world. Then brothers are killed for the sake of greed, and no one spares fathers or sons in the murders or kinship breaks." painting by Johannes Gehrts Wikipedia.
The Irish monk and geographer Dicuil wrote the work "De Mensura Orbis Terrae", which became known at the Carolingian court in the year 825 AD. He described islands in the ocean formerly inhabited by hermits, who, however, had now been displaced by vikings. He hands down a description from monks who had lived in "Thule" until the year 765 AD. There they had experienced the frozen sea, which lay a day's sail to the north. They said of Thule that "there was no darkness to prevent any from doing, what they wanted to do". Their description of the course of the sun as well as of the temperature fits perfectly with Iceland.
Extent of sea ice in the Arctic Ocean in winter - The yellow line shows the average spread of ice in January, from 1979 to 2000. The white area represents the distribution in 2011. Map DMI.
We must think that he believes "one day sailing" is in the summer. It must have been altogether impossible for the Irish monks to navigate the North Atlantic in winter in their small vessels that may have resembled the traditional leather-clad Irish curragh. This indicates that the extent of sea ice has been considerably bigger around 700-800 AD than it is today.
Monastery annals tell of increasing severe winters. Thus the winter 763-64 AD in many places in Europe was described as a winter with a huge snowfall and heavy losses of olive and fig trees in southern Europe.
Also, the winter 858-60 AD was clearly unusual severe. There was ice on the Strait of Dardanelles, and the ice on the Adriatic Sea near Venice was thick enough to support fully loaded wagons.
Reconstruction of an Irish curragh from Tim Severin's book "The Brendan Voyage" - To prove that Sct. Brendan really could sail from Ireland via the Faroe Islands, Iceland and Greenland to Labrador, Tim Severin built a curragh and carried out the journey. - It is obvious that such a vessel will not be able to cope with a winter in the North Atlantic. The legend of St. Brendan's journey contains no information on climate.
Also around 860 AD, the Norwegian Floki Vilgerdason navigated the waters around Iceland as the first Scandinavian. When he visited the northern Arnarfjord, he found it packed with ice; which indicates that the climate was considerably colder than nowadays, also in northern countries.
8. The Medieval warm period
Heat and cold periods through 2000 years compiled on the basis of the density of the growth-rings of pine trees in northern Scandinavia from the period 138 BC to 2006 AD - The blue line is the actual measurements. The red graph is result of a mathematical smoothing with a 100-year rolling average. The dotted line above and below the red temperature graph is representing uncertainty. The red dotted line at the top shows the general trend, namely that the Middle Ages were warmer than today, and that the Roman era was warmer than the Middle Ages. The vertical gray fields represent selected 30-year periods. The temperature scale to the left shows deviation from a mean temperature over the period 1951-1980. JJA means: June, July, August. Following data from Jan Esper, Ulf Buntgen, Mauri Timonen and David C. Frank "Variability and extremes of northern Scandinavian summer temperatures over the past two millennia." from 2012.
Advanced and accurate measurements of density of the growth rings in Northern Scandinavian pine trees have formed the basis for a highly accurate modern reconstruction of temperatures over the past 2,000 years. It shows that today's warm period is colder than the medieval warming, which again was colder than the Roman era. In modern times, there have been some particularly warm years, such as 2004, but they will be much less visible after a mathematical smoothing. Probably there have always been few years with exceptional heat or cold. It also follows from the historical accounts above about particular severe winters.
Sea surface temperature in the East China Sea (between Japan, Taiwan and China). It is seen that changes in temperature did not happen simultaneously over the whole Earth. The Roman Warm Period took place also in China, the cold spell of the Peoples migration period was significant, but not very long lasting, instead, it was replaced by the Sui-Tang heating period. The Medieval warm period was not particularly significant in East Asia and nor was the Little Ice Age. But the steadily falling temperature trend has been the same in China as around the Atlantic. From Chinese internet.
Jan Esper and his co-authors to "Variability and extremes of northern Scandinavian - - " conclude that their results "provide evidence of considerable warming during the Roman and Medieval warm period in larger scale and of longer duration than the twentieth century heating period." More specifically they identify the Medieval Warm Period to has taken place around 700 to 1300 AD and identify the warmest 30-year intervals during this period, which occurred from 918 to 947 AD in which period the June, July and August temperatures were about 0.3 degrees hotter than the hottest 30-year interval in the current warm period. Their findings differ from other researchers, who think that the Medieval Heating period began around 950 AD.
Norse settlements in Greenland. Ø stands for Eastern Settlement, M stands for Middle Settlement and V stands for Western Settlement. When the Norse settlements were on their peak, it is estimated from the size and number of farms that there have been between 3,000 and 5,000 Scandinavians in Greenland, which roughly corresponds to the number of inhabitants in Copenhagen at the same time. Photo Saga trails, Jette Arneborg, Danmarks Nationalmuseum, ISBN: 87-988378-3-4 Grønlands forhistorie, red. Hans Christian Gulløv Wikipedia.
In North America, there seems to have been a relatively warm and humid period between 700 AD and 1,200 AD, where maize cultivation spread along Mississippi up to Minnesota. In the waste piles of the past in Iowa archaeologists have found remains of bones of elk and deer, which are woodland animals, but after 1200 AD, they were rather abruptly replaced by bones of bison, which is a steppe animal, indicating a change to a drier climate.
Pollen analyzes from Lake Chad in Africa conducted by J. Maley from the Languedoc University in France shows a maximum of pollen from water-intensive plants in the period 700-1,200 AD, and that the water consuming plants gradually disappeared during the period 1,300 to 1,500 AD (Lamb).
The Medieval warming did not occur simultaneously across the Earth. In East Asia, it was partially replaced by the Sui-Tang heating period that occurred between about 500 and 800 years AD. The medieval warmth was most noticeable around the North Atlantic, but even in Antarctica, it can be traced.
The story of the Scandinavian settlements in Greenland is a good illustration of the Medieval warm period.
In 986 Erik the Red sailed to Greenland with 35 ships. Only 14 ships reached the destination, some sank, and others returned to Iceland. Most of the remaining 14 ships sailed into the fjords to the south around Julianehaab and founded the Eastern Settlement, others sailed a little further north and founded the small Middle Settlement around the present Ivigtut, and some sailed all way up to Godthaab fjord and founded the Western Settlement.
The Greenlanders built farms, houses and churches. There was both a monastery and a nunnery.
In Norse farmers' manure heaps, archaeologists have found big quantities of fish bones from cod. It shows that it generally has been warmer than in the present because, throughout, the 1900s, it has not been possible to fish for cod in Greenland waters; it's been too cold.
The Greenlander Thorkell Farserk was a cousin of Eric the Red. Once when he awaited Erik to visit, he would fetch a sheep that grazed on the island Hvalsey in Hvalseyjarfjord. Since he accidentally did not have a boat available, he swam out to the island, got hold of sheep and swam back again, that he could host his cousin.
Hvalsey church. Photo Number 57 at engelsk Wikipedia - Wikipedia
The distance to the island is slightly more than 3.2 kilometers. Dr. Pugh from the Medical Research Laboratories has given his assessment of this achievement to H. H. Lamb. From studies of Channel swimmers' endurance, we know that 10 degrees will be the absolute lowest water temperature, which allowed an experienced swimmer to swim this distance. In modern times, the water temperature in Hvalseyjarfjord usually is in the range of 3-6 degrees in the summer. Therefore, the water at that time must have been at least 4 degrees warmer than today.
In the Norwegian medieval document Kongespejlet (Kings Mirror) from about 1,250 AD is told about the sailing route to Greenland: "As soon as the great ocean has been crossed, there is such an abundance of ice that nothing like this is known from any other place in the whole world, and it is so far from land that there are no less than four or more days to travel to there over the ice, but this ice is more to the North-East and North off the land than from the south-west and West."
This must mean that when you sailed due west from Iceland in the summer, which was the original route, you would meet sea ice along the coast of Greenland. Nowadays there is usually no sea ice as far south in the summer. But maybe they sailed very early in the year.
The sailing routes of the Vikings to Iceland, Greenland and America. From McGovern and Perdikaris, 2.000.
About Greenland is further narrated in Kongespejlet: "But since you asked, if the country was free of ice or not, or it was covered with ice like the ocean, then you should know for sure that it is a small part of the country that is free of ice, but all the rest is covered with it, and people do not know, whether the country is large or small, because all mountain areas and also all valleys are hidden by the ice, so that you nowhere find opening on it." - "Few in number is the people in this country because there are few places, which are so ice-free that they are habitable" - "But since you ask about on what people are living in that country, since they do not sow grain, you must know that there yet exist many other countries, where the people do not sow, and though people are living in them, because humans do not live by bread alone. About Greenland is the saying is that there are good pastures and both good and large farms because they have much cattle and many sheep and produce much butter and cheese. On this the inhabitants have their living since for the most part, also meat and all kinds of hunting prey, both reindeer-, whale-, white bear- and seal-meat, On these things the Greenlanders have their living." - "But since you asked if the sun shines in Greenland, or whether it could ever happen that it was beautiful weather as in other countries, then you must know for sure that there can be beautiful sunshine and that the country most of the time at summertime can be called weather-good."
Reconstructed Viking house at L'Anse aux Meadows in Newfoundland" - After excavation of 2,400 Viking objects, there is no doubt that the Vikings discovered America long before Columbus. Photo Dylan Kereluk from White Rock, Canada - Flickr Wikipedia.
"But there is a big difference in the movements of the sun because as soon as it becomes winter, it is almost always night, but as soon as it is summer, it is almost all the time day. And when the sun goes highest, it has sufficient force for shine and brightness, but only little to warming and heat; however, it has so much force that where the ground is free of ice, it heats so much that it can provide good and fragrant grass; therefore, people can quite well live in the country, where it is thawed, but that is indeed very little." - "When it is stormy weather it happens with greater rigor there than in most other places, both in terms of the power of the storms and the violence of frost and snow."
But, it seems that the ancient document Kongespejlet was not completely well informed. Danish researchers from the National Museum have found small pieces of charred barley in Greenland Viking middens. The finding proofs that the Norse Greenlanders actually cultivated barley. They were able to produce the important main ingredient that is needed to brew beer.
"If the grain had been imported, it would have been threshed, so when we find parts not threshed, it is a very strong indication that the first Norsemen in Greenland cultivated their own grain", project leader Peter Steen Henriksen said. "One must assume, that if the grain had arrived in Greenland with a ship, it had been threshed first, otherwise it would take up too much space."
Visible ditches and furrows from medieval fields at Redesdale in Northumberland in England 300-320 meters above sea surface - Photo H. H. Lamb "Climate, History and the Modern World"
Another good indicator of climate is the spread of wineyards. When Wilhelm the Conqueror in 1086 AD prepared Doomsday Book, he recorded Wineries in 46 locations in southern England, from East Anglia to the modern Somerset. Today there are 400 English wine producers, but it must be seen in the light of the fact that modern wine-growers have developed wines that are more cold tolerant than the historical varieties. H. H. Lamb concludes that the medieval average summer temperature probably was 0.7 to 1.0 degrees higher than today, and the climate must have been less prone to frost in May.
At the abandoned village Houndtor in 400 meters above sea surface level in the highlands of Dartmoor in the county of Devon in England and at Redesdale in Northumberland near the border with Scotland 300-320 meters above sea surface level still exists visible traces of cultivated fields from the Middle Ages (Lamb). In this altitude, grain cannot be cultivated in modern times.
In medieval York archaeologists have found the presence of a species of the beetle "heterogaster urtica" that today lives only on nettles in sunny places in Southern England, which also indicates that Middle Ages was warmer than the present (Lamb).
In the Middle Ages two of the Sicilian rivers, Erminio and San Leonardo, were described as navigable, which today is quite impossible even with small vessels. This shows that precipitation was bigger in the warm climate of the medieval (Uriarte).
9. The Little Ice Age
The Rhone Glacier in north-eastern Switzerland on a postcard from 1870 compared to reality in 2006.
The development of this glacier has been very visible, as it can be seen from the nearby small town. During the last 120 years, the glacier has pulled about 1,300 meters back and left a trail of bare stone. Photo John Tagliabue New York Times.
There is no consensus on when the Little Ice Age started and ended, but let us stick to that the Medieval warming period ended and the Little Ice Age began around the year 1300 AD, as proposed by Jan Esper and his co-authors above. During the Little Ice Age winters were alternately mild and very cold just like today, but generally it was colder - and it became really cold around 1690 AD that may be designated as the culmination of the little ice age. Also around 1660 and 1770 AD winters were extraordinary cold. The winter of 1850 AD was also very cold, but then the temperature rose, and one can say that the Little Ice Age ended and the modern warm period began.
The cold weather came earlier at high latitudes than in southern Europe. In Greenland and in northern and northeastern parts of Iceland growing of barley was abandoned as early as about 1300 AD, while growing of wine in southern England and Northern France and cultivation of oranges in Provence of southern France were first abandoned about 1500 AD.
Eight time series of glacier advances and withdrawals through the Holocene during the last 6000 years. Most are not continuous, because they are based on morphological evidences as moraines, U-shaped glacier valleys etc. The Scandinavian graphs are continuous. To make it easier to compare, they are all presented as graphs. The graphs of the Alps are best supported by growth rings in trees and other documentation for the past 3,500 years. Except for Scandinavia and the Alps the exact times for glacial retreats are not known, and they are shown somewhat arbitrarily. The brown areas show, where the graphs have been concluded from indirect evidence such as residues of trees above the modern tree-line, buried topsoil etc.
When the graph is above the corresponding horizontal line, it indicates the warming and smaller glaciers than today, and when the graph is below the line it indicates cooling, and glaciers bigger than today. Note that the names of the mountains are placed at the start of the graph itself, and not at the connected horizontal line. All graphs end on the corresponding horizontal line, which represents the present.
Sources of information:
Franz Josef Land (An archipelago in the Arctic Ocean): Lubinsky et al., 1999,
Spitsbergen (An island in the Arctic Ocean, also known as Svalbard): Svendsen and Mangerud (1997) and Humlum et al. (2005).
Northern Scandinavia: Nesje et al. (2005), Bakke et al. (2005), IPCC (2007).
Southern Scandinavia: Matthews et al. (2000,2005), Lie et al. (2004), IPCC (2007).
Alps: Holzhauser et al. (2005),Jo'rin et al. (2006).
Brooks Range (In the northern Alaska): Ellis and Calkin (1984).
Western Cordillera-North America: Koch and Clague (2006).
Western Cordillera-South America: Koch and Clague (2006).
Glaciers of the Northern Hemisphere have typically been smaller in the past, and then they have grown down through the Holocene to a maximum during the Little Ice Age, after which they have pulled back a little.
From: "Mid- to Late Holocene climate change: an overview" by Heinz Wanner, Jurg Beer, Jonathan Butikofer with others.
The Little Ice Age seems to have been most noticeable in Europe and North America; but it could also be felt in China, Alaska, Caucasus and Himalayas; everywhere the glaciers increased. Only South America seems to have been quite unaffected.
Cultivation of heat demanding fruit trees, such as mandarins and oranges had to be abandoned in China's southern Jiangxi province, where these varieties before had been cultivated for hundreds of years. In the first half of the 1600s, China was plagued by droughts and floods. Unable to pay their taxes to the Ming emperors the peasants made revolt and thus paved the way for the Manchu conquest of China and the subsequent Qing dynasty.
The Western Settlement in the Godthaab fjord in Greenland was abandoned already around 1350 AD in the beginning of the cooling period.
Icelandic sagas tell that 1350 AD the bishop of the Eastern Settlement was reported that the Western Settlement was in need of assistance to drive away the aggressive Inuits, whom the Norsemen called Skrellings. The bishop sent a church envoy, Ivar Bardson, to the rescue. But when he arrived to the Western Settlement, he found the country deserted except for a few loose livestock. Taking the Icelandic sagas literally, it was more Skrellings than it was the worsening climate that caused the end of the Western Settlement. Apparently, the meeting between Inuits and Norsemen did not always process peaceful.
The Western Settlement largely covered what is today the municipality of Nuuk (Godthåb). The known farms and churches are identified on the map as some probable geographical names. The red dots indicate known farm ruins. Photo Saga trails, Jette Arneborg, Danmarks Nationalmuseum, ISBN: 87-988378-3-4 Grønlands forhistorie,red. Hans Christian Gulløv Wikipedia.
In 1723 the Norwegian explorer and missionary Hans Egede visited Godthaab district, and he asked the Inuits in Ujaragssuit near the ruins of the Western Settlements church, if they had destroyed it. They replied no and told that Qavdlunak (Norsemen) did it themselves, before they departed.
Ivar Bardsson lived in Greenland from 1341 to 1364. He wrote on navigation from Iceland to Greenland: "From Snefelsness in Iceland to Greenland by the shortest route, two days and three nights. To be sailed due west. - In the sea there is a reef called Gunbjørnsskaer. It was the old route, but now comes the ice from the north, so close to the reefs that no one can sail the old route without risking his life."
The last certain report we have about the Eastern Settlement is from some Icelandic travelers' account of a wedding in Hvalsey church: "Thousands and four hundred eight years after our Lord Jesus Christ's birth we were present, saw and heard in Hvalsoy in Greenland that Sigrid Bjørnsdatter were married with Thorstein Olafson." Thus it is written in the laconically Icelandic sources that tell of Norse life in Greenland. The wedding took place - the first Sunday after Cross Fair - 14. September 1408 AD.
Left: Reconstruction of a typical Nordbohus in Greenland. Northern houses in Iceland, on the islands in the Atlantic and many places in Scandinavia were of a similar type.
Right: The interior of a typical Norse house. The two rows of columns, behind which there were sleeping places, and the hearth in the middle is very characteristic of the Viking Age. Photo Greenland Travel.
In 1492 Pope Alexander VI expressed, however, his anxiety about the situation in Christendom's northern outpost: "The Church in Garda lies at the end of the world in Greenland, and the people, who dwell there, are accustomed to live on dried fish and milk due to the lack of bread, wine and oil - shipping to that country is very irregular because of widespread ice on the water - no ship has called their shores for eighty years, it is believed - or if travel takes place, it is thought, only in August - and it is also said that no bishop or priest has had office in eighty years or so." - "The people of Greenland have been abandoned by the church so long that they have returned to the "pagan practice", wrote the Pope as he offered the Benedictine monk Matthias Knutson the position as bishop of Gardar, if he would be willing to travel there and lead the people back to Christianity.
Carbon-14 analysis from bones taken from Norse cemeteries in Greenland, suggest that the Eastern Settlement existed until about the year 1500 AD.
During the "Little Ice Age" in Europe flourished life on frozen canals in the Netherlands. People were skating on the ice and shopped in market stalls, which was established on the ice. It was a popular motif for several painters - Painting by Francis G. Maye.
There are told many Eskimo legends about battles between Norsemen and Inuits. They are about Norsemen, who kill many Inuits, and Inuits, who kill Norsemen. Hans Egede made many trips along the coast in search of the missing Norsemen. When he 1723 came to Julianehaab district, it seemed to him that the Inuits there were "quite beautiful and white" as opposed to those, whom he had previously met. His son Niels Egede was the first to learn the Inuit language. To him the Inuits told that the Norsemen were attacked by pirates, and their women and children fled to the Inuits. When they returned all the Norse houses had been burned down, and the men have been killed. The Inuits then went deeper into the fjord and married the Norse women.
A ship commanded by John "Greenlander" was in 1540 traveling from Hamburg to Iceland, but was blown off course by a storm. The crew went ashore in Greenland at the Eastern Settlement. They found a settlement that looked like those in Iceland, but the buildings were empty apart from the body of an old man dressed in leather with a cap of cloth lying on the floor in a house with a worn knife in his hand.
Temperature and humidity near Bern and Zurich in Switzerland as an average for each decade from around 1520 to 1820 AD - The solid line represent temperature and the dotted line represent humidity - It is seen that the Little Ice Age peaked around 1690. In addition, it can be seen that there has been widespread frost in the spring months, March, April, May. Even in the summer months, there has been freezing weather - Prepared by Dr. Christian Pfister from the Geographical Institute at the University of Bern - From "Climate, History and the Modern World" by H. H. Lamb.
When Hans Egede in 1741 after his stay in Greenland lived in Copenhagen, he wrote about a monk of Greenlandic blood: "At a German Autorem named Dithmarum Blefkenium I otherwise found an account about a monk, who was supposed to have been born in Greenland, with the bishop from that same place Anno 1645 (presumably it must be 1545) and should have travelled to Norway and since lived in Iceland l546, where he, according to his report, personally should have spoken to him. This same monk should have told strange and curious things about a Dominican Monastery in Greenland called Sct. Thomas Monastery, into which he in his childhood had been submitted by his parents with the intention that he there should become monk."
Also another source, which Hans Egede mentions, talks about this monk. That is a Danish sea captain named Jacob Hall, who had also met the Greenlandic monk and described him as follows: "He had a wide face, and his color was brown".
Around 1623-25 AD Bjorn Jonsson from Skardsa in Iceland reported that he had found pieces of wreckage on the beach, which were typical for ships built in Greenland.
In 1529 a huge Turkish army under Sultan Suleyman had to withdraw from a siege of Vienna due to poor military results, cold rain and heavy snow as early as October.
The Turkish siege of Vienna in 1529 - Due to cold rain and heavy snow already in October the Turks had to withdraw from a siege of Vienna in the middle of the month. They lost many soldiers and equipment during the retreat to Constantinople through snow and mud. Photo Peter Snayers Wikipedia.
According to a weather diary from Zurich from the period 1546-1576 AD the frequency of snowfall increased 44% in the first part of the period until 1563, and increased further by 63% in the last part to the year 1576 AD (Lamb).
Tycho Brahe's observations in Denmark from 1582 to 1597 indicate a winter temperature, that was 1.5 degree below the average temperature of the period 1880 to 1930 AD. Furthermore, Tycho Brahe's observations tell that wind from the east was dominant. In his notes southeast was the most frequent wind direction (Lamb).
A priest in eastern Iceland named Olafur Einarsson wrote in the early 1600s a poem that illustrates the Icelanders' problems:
Formerly the earth produced all sorts
of fruit, plants and roots.
But now almost nothing grows -
Then the floods, the lakes and the blue waves
Brought abundant fish.
But now hardly one can be seen.
The misery increases more.
The same applies to other goods -
Frost and cold torment people
The good years are rare.
If everything should be put in a verse
Only a few take care of the miserables -..
The Battle of Tybrind Vig on 30 January 1658. Charles X Gustav crossed the ice on the Lille Bælt with 10,000 men at night and thereby completely caught the Danes by surprise. Painting by Johan Philip Lemke.
In winter of 1657-1658 war broke out between Denmark-Norway and Sweden. By this time the Swedish King led war in Poland. The winter proved to be unusually cold, and all the Danish waters became completely covered by ice. By the announcement of the Danish declaration of war, the Swedish King Carl Gustav lost any interest in Poland and turned immediately against Denmark. He led his ten thousand men with horses and a few cannons over the ice from island to island, and soon they showed up in front of the walls of Copenhagen. At the same time, the Danes were unable to use their fleet because of the ice. Denmark-Norway was completely unprepared for this development, and King Frederik 3 asked for negotiations. At the Peace of Roskilde, Denmark-Norway had to submit Scania, Blekinge, Bornholm and the Norwegian provinces Bohuslen and Trondheim Province.
Around 1580 AD, the Denmark Strait between Greenland and Iceland in several summers was completely blocked by pack ice. In the winter of 1695 AD Iceland was completely surrounded by sea ice.
Already about 1615 AD, the Faroe cod fishing began to fail, and through the thirty years under the Little Ice Age climax 1675-1704 AD, there were absolutely no cod in Faroe waters. A recent Danish study has shown that cod can thrive in many different temperatures, but they seem to prefer temperatures between 1 and 8 degrees when they breed. Maybe water temperatures in the North Atlantic were too low. Through most of modern time, it has not been possible to fish for cod in the waters around Greenland, probably for the same reason.
The Medieval warming and the Little Ice Age. - From the BBC documentary: "The Great Global Warming Swindle".
In Norway new small glaciers formed in the mountains of Hardanger during the maximum of the Little Ice Age. Between 1690 and 1710 AD there were numerous cases in Norway about farms that were destroyed by advancing glaciers. Thus the Nigard glacier advanced 3 km between 1710 and 1743 AD and destroyed thereby a farm named Nigard. The owner sent a letter to King Frederick 5. in which he asked for compensation for the destruction.
Also in North America, the winters were very cold and long. The inhabitants of the small English colony of Jamestown, which had been founded in 1607 on the coast of Virginia in the current U.S., complained about unusual long and cold winters. Quebec's founder Samuel Champlain noted that in June in the year 1608 AD there was ice that could bear at the shores of Lake Superior.
10. The Modern Warming Period
There is no consensus on when the Little Ice Age ended, and the Modern Warming Period began, but I will stick to around 1850 AD, as proposed by Jan Esper, Ulf Büntgen with others.
The global temperature in the modern warm period - The red dotted line is results from GISS, which is Goddard Institute for Space Studies at NASA. The dotted green line are the results from the UK Met Office Hadley Centre compiled by the Climatic Research Unit from the University of East Anglia. The solid red line is the results from the Goddard Institute for Space Studies at NASA's results, which are mathematically smoothed with a 10-year rolling average. The solid green line is the results from the UK Met Office Hadley Centre, which are mathematically smoothed with a 10-year rolling average. The horizontal 0.0 line represents the average of temperatures from the period 1850 - 1899 (UK Met Office Hadley Centre) and 1880-1899 (NASA GISS). - The graph is from the European Environment Agency.
Since 1850, the Earth's average global temperature has increased by around 0.8 degrees compared to the average of the period between 1850 and 1899. Europe has warmed 1.2 degrees, which is more than the global average.
Painting by Nils Simonsen "Episode of the retreat from Dannevirke on 5 - 6. February 1864 "painted in 1864.
It started cold. In January and February 1864 AD, when the Danish soldiers waited behind the ancient defence-dike Dannevirke on the Prussian and Austrian armies, both the wide marshes of western Schleswig, that should protect their right flank, and the fjord Slien, that should protect their left flank, was completely frozen, and precisely therefore, they made an organized retreat to the Dybbøl redoubts to avoid encirclement. It also seems that it has been pretty cold in the trenches of Flanders during the First World War.
There was occasionally ice on the Thames. In 1924 the inner Danish waters were completely frozen, and one could walk from Scania to Copenhagen.
Two young women from Malmø in front of the frozen øresund in 1924.
Some of the older generations of Danes can probably remember that their family in the countryside had a sleigh standing in a dusty corner of the barn. At the beginning of the twentieth century it was as a matter of course that there was snow in winter, and when you wanted to go somewhere, you simply harnessed the horses for the sleigh. Perhaps they were used for the last time during the severe winters in the 1940's.
On 8 February 1942, in Brande in Jutland was measured -29℃, which was the lowest temperature of the month. It is the coldest February day ever measured in Denmark. From 5 January until 25 March in 1942, there was not a day in Copenhagen without freezing weather.
In North America, the western prairie was the last land to be settled. It happened at the end of the 1800s. The settlers had a few good years, and then the problems of locusts and drought began to set in.
On April 15, 1935, Boise City in Oklahoma USA was hit by a gigantic dust storm, which blew the top layer of topsoil off the fields. This comprehensive disaster which struck the American Midwest is called "the Dust Bowl". Photo Times Union.
The "Dust Bowl" of the 1930's was caused by degraded soil and years without rain, entire fields took off to the air in big black dust storms that could blow for days. "There was dust everywhere. It came into the houses, in the food and between the teeth" a settler told. Hundreds of thousands of people loaded the few possessions, they had, and fled to California - as in Steinbeck's "The Grapes of Wrath".
Also in China, very large areas of newly reclaimed land in the provinces of Shaanxi and Inner Mongolia were reduced to desert in the first half of the 1900's.(Lamb)
Ice winter in 1956 at Dalum near Odense - Denmark. Photo unknown origin.
From about 1915 through the interwar period, temperatures rose, and by the end of World War 2, the average temperature had risen about half a degree since 1850. This warming period started before cars, airplanes, and other CO2-emitting means of transportation were even invented, and the man-made CO2 emissions were quite negligible. Which indicates that it was a development that humans had no influence on.
During the industrial boom from 1950 to 1980, the industry flourished like never before, supplying cars, refrigerators, airplanes and all kinds of consumer goods.
Emission of CO2 from fossil sources from 1800 to 2000. Although for the first time in world history, some CO2 was emitted in the period 1950-82, the temperature still fell. From 1980 to 2000, CO2 emissions increased quite a bit, but the temperature, on the other hand, increased relatively significantly. Which again indicates the lack of cause-effect relationship between CO2 in the atmosphere and world temperature. Wikipedia.
The most of anthropogenic CO2 has been emitted precisely in this period. Supporters of the theory of anthropogenic global warming believe that CO2 emissions have made the global temperature to go up. But nevertheless, in the period, where the industrial boom took place, the temperature dropped over four decades and Northern Europe and North America experienced again winters with lots of snow.
The ice winter of 1981-82 was the coldest that has ever been measured in Denmark. Winter already started on 7 December and on 17 December was 25.6℃ freezing in Døvling in Jutland during the day. In the month of January was meassured 31.2℃ at Hørsted in Thy. All four state icebreakers were in action.
1984-85, 1885-86, 1986-87 were three ice winters in a row. The Danish waters were covered by 20 cm thick ice. Every year all four icebreakers were in action.
Icebreaker in Store Bælt of Denmark in the winter 1981-82 - Photo Ove Hesstrup Hansen.
First, during the economic crisis in the late eighties temperature again began to rise.
One-third of all human CO2 emissions have taken place since 1998. However, the global temperatures have not increased in that same period, which all together strongly indicate that the CO2 emitted by humans is not the cause of the increased temperature.
The theory of man-made greenhouse gases as the cause of global warming assumes that the long-wave heat radiation from the heated Earth is blocked by CO2, which acts like the glass in a greenhouse and thereby prevents heat from radiating back into space. The long-wave outgoing heat radiation from the greenhouse is stopped by the glass, and thereby the energy in the radiation is converted into heat in the glass according to the thermodynamic law of conservation of energy. The CO2 in the atmosphere is supposed to act in similar way - hence the name the greenhouse effect.
Left: A locomotive is dug free of snow on the Roskilde railway - Denmark - in winter 1942.
Right: Ice drifts at Skamlebæk Strand next to the radio station at Sejerø Bugt in 1942. Photo bibod Gallery.
Therefore, serious scientists assume that if the theory of man-made global warming due to the greenhouse effect is true, then one should be able to measure a warming in the atmosphere. In the same way that the outgoing long-wave heat radiation deposits its energy as heat in the glass in the greenhouse, so the outgoing long-wave heat radiation from the earth's surface and the clouds should deposit its energy as heat in the atmosphere, as this is where it is stopped by CO2, it is said.
On 17 January 1987, Falck in Fredericia digs the last car out of the large masses of snow on the motorway between Børkop and Fredericia. The car was completely buried in snow and lay one meter above the road. There are indications that it has been pushed to the side or lifted up into the three meter high pile of snow at the roadside by the snow removal machines. Photo Kurt Hardi Vejle Arkiv.dk.
But regardless of whether one measure with weather balloons or satellites, no warming in the atmosphere can be detected, on the contrary. It is established that the warming takes place at the earth's surface and not in the atmosphere, which suggests that the theory of man-made global warming due to CO2 emissions is not true.
It is true that both the CO2 content in the atmosphere and the global temperature have risen in the modern warming period; But the warming does not fit the theory, it happened in the wrong place and at the wrong times.
11. Sun spots
The sun as it looked like on 8. June 2013 - from spaceweather.com - For a very long time no sunspots had appeared and experts had begun to fear of a new Little Ice Age. But now, finally, some small spots showed up.
On the Sun one can see some dark spots which are called sunspots. They are typical of the size of Earth, which means between 4,000 and 50,000 kilometers in diameter. The spots are about 1,000 degrees Celsius cooler than the rest of the sun's surface, which is approx. 5,750 degrees. Contrary to what one might believe, the sun radiates most energy when there are many sunspots, because simultaneously with the spots warmer areas occur around them, which more than compensate for the lower temperature of the spots.
Sunspots were first described by the Greek philosopher Teofrastos from Lesbos in 300 BC. He saw some strange black spots on the sun's surface. There are also earlier reports from China, which tell us that sunspots have been seen with the naked eye; it is sometimes possible - with caution when the sun is low in the sky and blurred by haze. Galileo directed his telescope towards the sun in 1613, observed, described sunspots systematic and issued a "Letter on sun-spots".
Some sunspots grow very large lasting several months, others become only a few hundred square kilometers big and disappear within a few days. Since the mid-1800's we have known that the number of sunspots varies with a period of 11 years so that every 11 years there will occur maximum sunspots.
The daily number of sunspots since 1900 from the Solar Influences Data Analysis Centre (SIDC). Note the 11-year cycle. We are just now in 2013 about maximum sunspot activity of period of 24, which run from around 2009 to around 2020. Maximum sunspot activity should occur about 2014-15, but the number of daily sunspots is never the less still quite low. Photo SIDC Climate4you.
Systematic counts of sunspots have been routine since Galilei invented the telescope. During the Little Ice Age the astronomer Cassini from Paris reported in 1671 that he had found a sunspot, and it was the first one that he had seen in many years. The Englishman Edward Maunder studied ancient records on sunspots, and came to the conclusion that during the Little Ice Age there were virtually no sun-spots. The period was named the Maunder minimum.
Carbon-14 and Beryllium-10 are created when cosmic rays enter the atmosphere. Photo unknown origin.
It is such that, when there are many sunspots, the solar magnetic field will be strong and deflect much cosmic radiation directed toward the Earth. When there are no or only a few sunspots, the Sun's magnetic field will be weak allowing more cosmic radiation to hit the Earth.
When cosmic rays hit Earth's atmosphere new isotopes are generated, especially carbon-14 and beryllium-10. When the cosmic radiation is strong, there will be formed many of these isotopes, and when the cosmic radiation is weak, there will not be formed as many. Both carbon-14 and beryllium-10 are unstable isotopes that decay over a very long time.
By analyzing historical records, carbon-14 content of trees growth rings and beryllium-10 content in ice cores from the ice caps, scientists have been able to reconstruct past levels of cosmic radiation and identify other periods, when the Sun's activity and its magnetic field has been weak, such as the Oort Minimum, Wolf Minimum, Sporer Minimum and of course Maunders Minimum.
Solar activity through 1.000 years as revealed by carbon-14 analysis. Oort minimum refers to a minor cold period in the Medieval heating period, note also that Wolf and Spurs minimum occurred in the Little Ice Age. The graph ends around all-time maximum in 1950. The activity has since then decreased significantly. Photo Earth Science.
There is a correlation between the number of sun-spots and the intensity of the solar radiation that reaches Earth. When there are many sunspots the suns radiation will be stronger. Currently, the radiation from the sun has a strength of 1,370 W/m2 on an imaginary surface perpendicular to the line between the Sun and Earth located above the atmosphere at the equator. Solar irradiance on this surface oscillates with an amplitude of 1.2 W/m2 between the maximum and minimum number of sunspots. That is only 0.09% of the total radiation - It will not at all be noticeable!
But, however, there are very powerful amplification mechanisms.
The radiation from the sun has an intensity of 1,370 W/m2 on an imaginary surface perpendicular to the line between the Sun and Earth located above the atmosphere at the equator. Photo unknown origin.
The sun has a magnetic field which is several thousand times stronger than Earth's. Currently, the Sun field is about 2,000 gauss, which should be compared to Earth's field that is 1 gauss. It stretches far into space, entirely out beyond Pluto's orbit. Since 1990, the solar magnetic field has decreased from 2,700 gauss to the current about 2,000 gauss.
Sunspots are regions on the Sun with intense magnetic activity. Many sunspots are a sign that the solar magnetic field is strong and few sunspots mean that the field is less strong.
Eigil Friis-Christensen and Henrik Svensmark found a very close correlation between Sun's magnetic activity and Earth's temperature - From the documentary "The Cloud Mystery".
The Sun is a star in the Milky Way Galaxy, which contains at least 100 billion other stars. Some stars explode as super novaes thereby emitting particles, may be electrons, protons, neutrons, or ionized atomic nuclei, which enter Earth's atmosphere - sometimes with near the speed of light. Earth and the solar system are thus constantly exposed to cosmic radiation.
But only some of the cosmic rays hit the Earth; a big part is deflected by the Sun's strong magnetic field. When there are many sunspots, and the Sun's magnetic field is strong, it will deflect much radiation and the cosmic radiation, which enters the atmosphere will be weak. But a lazy sun with few or no sunspots will have a weaker magnetic field and deflect a smaller part of the cosmic radiation. The radiation, which enters the atmosphere, will, therefore, be more intense.
The Sun has a very strong magnetic field, which extends all the way to Pluto's orbit and protects the entire solar system by deflecting a large part of the cosmic radiation. Photo ru:User Passenger Wikipedia
The Danish scientists Eigil Friis-Christensen and Henrik Svensmark have demonstrated that clouds are created by cosmic radiation. This means that when the cosmic radiation, that enters the atmosphere, is strong, the Earth's cloud cover will be extensive, and when the cosmic radiation is weak, Earth's cloud cover will be less extensive.
We imagine generally that clouds are composed of water vapor. It is not the case since water vapor is a transparent gas. Clouds consist of aerosols, which are clumps of molecules of different kinds, mainly water molecules. Aerosols are formed around a particle or ion.
When a cosmic particle enters Earth's atmosphere with tremendous speed, it beats the electrons lose from all the molecules that it hits on its way thereby creating a trail of ions that quickly find together creating aerosols in an atmosphere containing water vapor, the aerosols will then create clouds.
When cosmic radiation particles enter Earth's atmosphere with great energy, they create ions and thus aerosols, which accumulate into clouds. Drawing Simon Swordy NASA.
During the last 100 years, until the beginning of the new millennium, the Sun's magnetic field has doubled. Precisely for this reason, the cosmic radiation that hits Earth dropped by about 15%. This caused that there are now fewer low clouds over the Earth. Low clouds have a cooling effect, and as there have been fewer of them, we probably have here the explanation of the Modern Warm Period. Today Earth's average cloud cover is about 60% - 70%. Small changes in cloud cover bring about changes in climate.
We have often on our own bodies learned that cloud cover has a marked cooling effect. We are lying on the sand at the beach after a swim, bathed in sunshine. Then a cloud passes the sun, and immediately we feel the heat disappear.
During the Little Ice Age, about 1700 AD was a period of practically no sunspots at all. We can, therefore, assume that the solar magnetic field was weak and therefore allowed a great deal of the cosmic rays to enter the Earth's atmosphere. The cosmic rays caused clouds to form to fairly large extent. This extensive cloud cover reflected the sun's rays from their white upper side preventing the sun to heat the Earth, and therefore the Little Ice Age was such a cold period.
Average annual number of sunspots since 1600 from "Climate, History and the Modern World" by H. H. Lamb.
Eigil Friis-Christensen and Henrik Svensmark's theory, that variations in the solar magnetic field are the cause of climate change, challenges the prevailing theory that man-made CO2 is causing global warming.
Christensen and Svensmark's theory is based on simple assumptions and simple experiments, which can be confirmed by experience of our daily lives; such as that when a cloud passes the sun, you will feel that it gets colder. The fog chamber is a simple device, which has been known since C.T.R. Wilson in 1927 won the Nobel Prize for the invention.
Earth's temperature since 1880. It can be seen that during the industrial expansion in the postwar period, when most CO2 were emitted, the temperature dropped down to the 1980's ice winters. First with the economic crisis of the eighties it again began to rise - From the documentary "The Great Global Warming Swindle".
The theory of anthropogenic CO2 as the cause of global warming is far more subtle and speculative, and it requires to a greater extent that common people blindly believe experts.
The content of CO2 in the atmosphere today is around 400 ppm (parts per million), which is 0.04%, i.e. just under four ten thousandths. It's really not immediately obvious that a marginal change in such a small volume can change the climate in any measurable way.
Traces from trajectories of elementary particles in a Wilson cloud chamber. Photo unknown origin.
The enormous popular support for the theory of man-made CO2 emissions as the cause of climate change is apparently due to the fact that the theory is in harmony with our Christian culture's idea that we are all sinners. Moreover, the accusation against the industrial companies as the main responsible for the emissions fits well with the feminists' attack on the white men and the socialist idea of the evil capitalists.
