Little Ice Age and the erratic climate changes – part 3

THE LITTLE ICE AGE 1280-1850 A.D. – The Roman Warming, The Medieval Maximum, The Dark Ages, Viking settlement, Thorvald Asvaldsson of Jaederen, Eric Asvaldsson, Black sea freezing, Ian Plimer, Greenland Vikings, Iceland Vikings, The Little Ice Age, Ladune, Bardsson, Glaciation, Gunbiernershier, Newfoundland, Groves, Snefelsness in Iceland, lichen, sunspot cycle.

Let us examine what many authors have concluded about this interesting period. To begin with there is certainly no consensus over its beginning and end nor the extent of the various periods. However there seems some consensus that the Maunder minimum was the worst of the four proposed periods.

Initially, I will give a synopsis about what many authors have concluded about the dramatic weather changes of the last two thousand years and the fluctuating weather patterns that at some stages have bought human prosperity and at other times drought, reduction in population, race movements and not least, abandonment.

Firstly however let us look at a graph that a conglomeration of Ice core studies from Camp David, GISP and Antarctica tend to summarize over the last 100,000 years (see Plate 1: GISP 2 and Plate 2: SUMMIT).These are based on oxygen 18 studies (that theoretically show annual precipitation rates, ash fallout from Volcanoes and various other Isotopes that express cosmic ray activity (from the sun) and ion concentrations from other elements. My purpose in this is to show the incredibly fluctuating weather of this vast period.
solar cycle 24 sunspot number prediction little ice age

Compared to this the last two thousand years has been a period of high stability. For instance the Younger Dryas has been associated with mega faunal extinction of Mammoths, Sabre tooth Tigers and a host of other extinct animals. It is also related to the disappearance of the Clovis Indian culture in the North America approximately 10,000 years ago . Now this may not have been due to climate change but it was certainly associated with this phenomena. The little Ice Age by comparison is a mere Hiccup as is the twentieth century warming. With these more dramatic periods in mind let us move on to the present era.

The Major periods of the last two thousand years(2)

The Roman Warming: 250 BC – 450 AD

Citrus trees and grapes(3) were grown as far north as Hadrian’s Wall and Olive trees grew in the Rhine valley of Germany. Temperatures were around 6 degrees warmer than today. Central America was wetter than now(4).Central Africa was the wheat bowl of the Roman Empire where now deserts have taken over. Asia responded with huge population increases around 300 A.D.(5)

The Dark Ages: 535 – 900 AD

The Dark Ages was a cold and wet time for the human race. Procopus wrote “It was cold, there was famine, war, there was change of empires and the stressed human beings succumbed to the plague.” Around 540 AD trees stopped growing. From Constantinople

“The sun gave forth its light without brightness, like the moon during the whole year. It seemed exceedingly like the sun in eclipse”.

Although obviously anecdotal but records that recorded the Black sea freezing in 800A.D.801 A.D .and 829 A.D. cannot be mere hearsay. This freezing has not happened since(6).


The Medieval Warming: 900 – 1300 AD

This final precursor to the “Little Ice Age” marks a generally prosperous period for the human race(7). Great population expansion took place. It is estimated that during this period the European population increased 50%, probably due to large food surpluses(8). For instance England’s population increased from 1.4 million to 5.5 million whilst the population of France tripled to 18 million(9). This is the era of the Norman conquests where population pressures led to a search for more land. Some believe that this was a global phenomena(10). Although it too had its periods of erratic behavior it was marked, in balance, by general prosperity. Summers were longer and warmer. Rainfall was plentiful and crops, by and large were plentiful. For instance, in Norway(11), cropping occurred higher up in what are now exposed heath lands. The importance is the comparison with the ages that followed.

Viking settlement before the onset of the Little Ice Age – a case study

There was a large increase in population in the known world and an era of colonial expansion. During the years 800-1200, Iceland and Greenland were settled by the Vikings. The warm climate during the Medieval Warm Period allowed this great migration to flourish. Drift ice at later dates posed the greatest hazard to sailors but reports of drift ice in old records do not appear until the thirteenth century(12). Various reasons for the migration have been cited but certainly the classic ones of escape from oppression by ruthless rulers, escape from war and a search for greener pastures are the main contenders. The bones of a variety of domestic animals from cattle, sheep, pigs and goats collected from archaeological sites reveal the existence of large farms with large productive pastures. The settlement extended to Greenland when the son of Thorvald Asvaldsson of Jaederen (Eric) was banished from Iceland for killing two men. He had heard of the discovery some time before and converted his misfortune in the foundation of a new colony which Icelandic chroniclers said was named to attract new settlers. The initial settlement was on a deep fiord on the south-western coast. Warmer Atlantic currents met the island there and conditions were not much different than those in Iceland.

Eric was able to draw thousands to the three new areas. The Greenland Vikings lived mostly on dairy produce and meat, primarily from cows. The vegetable diet of Greenlanders included berries, edible grasses, and seaweed. The growing season in Greenland even then was very short. Frost typically occurred in August and the fiords froze in October. Before 1300 trade with European countries was brisk with many ships plying to and fro trading timber, iron, and salt, corn in exchange for furs, skins (polar bears, fox, walrus and narwhal tusks) butter, cheese and wool(13). Expansion was in fact prolific enough for the Pope to send a bishop to Greenland.

In summary the Medieval Warm period was by the consensus of many historians and scientists a period of generally warmer times with relatively predictable climate. It was amenable to flourishing crop production and the expansion of the human race. Records cited from Frankfurt for instance record vineyard growth some 200 meters higher in Germany than at present(14). This implies a temperature between 1.0 to 1.4 degrees C warmer than now. On the basis of pollen studies China was 2-3 degrees C warmer than now. Tree ring growth, ice cores, sediment cores, glacier retrenchment, see ice reports plus a wealth of anecdotal evidence enforce this conclusion. The Little Ice Age that was to follow dramatically changed this picture.

The Little Ice Age

Although as we have noted the Little Ice Age is a scientific reconstruct with loose periodical boundaries there appears overwhelming evidence(16) that erratic climate with excessive cold and wet periods occurred during the period 1280AD to 1350 AD. Although many scientists and historians differ on the precision of the minima boundaries the overwhelming majority recognise there were times over this period that was not only much colder and wetter but also more erratic. The four minima were also tied into periods that were somewhat drier and warmer but still on average colder than the present climate optimum. ( see Plate 4, Plimer p.110).In fact as this graph and the graph in Plate four show it became as low as 2-3 degrees Celsius lower than the present climate average. On chart four we can clearly see the Wolf, Sporer, Maunder and Dalton minimum. This chart is an average summation by Plimer of many scientific sources. I quote Plimer(17),

“The methodology of science is such that new data and the resulting conclusions are critically analysed, repeated, refined or rejected. The hockey stick ( Mann et al. IPCC) was contrary to conclusions derived from thousands of studies using boreholes in ice, lakes, rivers and oceans, glacial deposits, flood deposits, sea level data, soils, volcanoes, windblown sand, isotopes, pollen, peat, fossils, cave deposits, agriculture and contemporary records”

Thus Plimer contends that the Little Ice Age minima’s were a reality. But what were the causes of these unexplained phenomena? Certainly in these ages the effect of humans on the planet could not be a contender whatever the arguments put forward in the present era to industrial pollution. At this stage we must examine the part sun spot minima and maxima play on the climate stage. This is not merely curiosity but will help us understand the effect these cycles have on famine. This returns us to our contention that at the little ice age minima’s significantly larger effects were accumulated that were in some cases go beyond the ability of humans to control.

Lately a number of papers have been written that links sunspot activity and therefore solar flux into climate control. By flux we understand cosmic ray emission (various positive ions and electrons emitted primarily by the Sun but also from outside the solar system) these interact with the Earth’s Magnetosphere (see Plate 7) and today is reflected in the intensity of the Aurora Borealis and Aurora Australis. Both of which put on dramatic displays when there is coronal mass ejection. Both Parker(18) and Lockwood(19) in separate papers were able to tie sunspot maxima and minima into solar luminosity, isotope concentrations that reflect precipitation and primarily drier, wetter, windier and hotter or colder times. It appears that the sunspot eleven year cycle is linked into the severity of hurricanes and droughts. This is the thinking of the U.S National Centre for Atmospheric research (NCAR). In Australia Baker(20) from Armidale’s University of New England believes this gives him a vehicle to predict times of drought. His tracking of sunspots since records were kept in 1876 shows that switches in the sun’s poles and magnetic field every eleven years are consistent in their effect on Australia’s weather.

Indeed if go back to a compilation of sunspot records, which curiously, have been kept for quite four centuries (see Plate 6 A), it shouldn’t surprise us that these fit in well with times of drought. Note that at times of prosperity the sunspot activity is high. Grain prices are low. At low sunspot activity we have an association of crop failure and high grain prices. (See Plate 6)(21). What actually drives the sunspot cycle is open to theory and need not concern us here apart from the strong contention that the major gas planets Jupiter and Saturn are involved. More importantly there must be a further factor that drives the whole sunspot cycle up and down and this is what causes deeper and colder maxima and minima. How and if these two are related is beyond the scope of this paper except to point out drought varies over a full twenty two( average) year cycle with an eleven year( average) maxima to minima turnaround time. Let us now see the effects of these climate variations of the Little Ice Age

Case study on the settlements in Iceland and Greenland in the Little Ice Age

Greenland

We have previously mentioned the successful colonies founded in both countries. Both countries suffered badly under the various stages of the Little Ice Age but the Greenland settlement was finally engulfed by sea ice and cold and the population perished. What happened? By 1300 AD more than three thousand Vikings and a few Inuit populated over three hundred farms(22) along the west coast of Greenland. Around 1200AD the weather started to deteriate. Drift ice affected the trade routes and eventually forced new and dangerous routes to be adopted(23). Poor crops became a regular occurrence. This in turn affected the production of meat. Fishing started to be driven farther off shore. This caused fewer ships to visit Greenland(24).Ladune quotes Bardsson.

From Snefelsness in Iceland, to Greenland, the shortest way: two days and three nights. Sailing due west. In…the sea there are reefs called Gunbiernershier. That was the old route, but now the ice is come from the north, so close to the reefs that none can sail by the old route without risking his life

Both Greenland and Iceland became stormier and windier as the Little Ice Age progressed .This is witnessed by the increase in sea spray in ice core studies(25).

Iceland

The Vikings in Iceland suffered badly at the hands of the Little Ice Age. They did not become trapped and perish as the Greenlanders did but the population became greatly diminished. It fell from approximately 78,000 in 1095 AD (according to tax records) to around 72,000 by 1311 Ad. But by 1703 AD it had shrunk to only 50,000(30). And by the 1780’s it was further reduced to 38,000. They like the Greenlanders shrank in stature from five foot eight to five foot six. Further with little hay to feed the livestock, sheep died in their thousands. By 1200 AD only short season barley was being grown. By 1500 AD all grain growth was stopped and henceforth only fishing could be pursued. Even this was driven out further to sea by the huge growth in sea ice. Cod was the main staple but even this moved south and Iceland struggled to survive. Four glaciers were studied with the 19th century revealing the biggest area of glaciation. Studies of lichen help us establish the duration and extent of ice in Iceland during the Little Ice Age.(31)

Peter Mungo Jupp

1 Firestone 2008
2 Plimer 2009 – pp50-99.
3 Allen 1961 p
4 Laird.2003. pp2483-2488
5 Lebreiro et al.2006 pp1013-1016
6 Plimer.2009.pp50-99
7 Grove 1988.
8 Plimer2009.p64.
9 Plimer 2009. p65.
10 Broecker2001.pp1497-1499.
11 Arbman.19661.p28.
12 Bryson1977
13 Scott 2010. .http://www2.sunysuffolk.edu/mandias/
14 Plimer cites Arendes2007.p65.
15 Tagami.1993. pp720-729.
16 Plimer 2008.p110.
17 Plimer 2008.p.80.
18 Parker 1999.p416
19 Lockwood 1999.ppp437-439
20 Baker2006. New England Uni
21 Berner 2001.
22 Schaeffer 1997.pp34-38
23 Lamb 1995
24 Bryson 1977.
25 Plimer quoting Kreutz 2008.p.78.
26 Scott 2010http://www2.sunysuffolk.edu/mandias/
27 Lamb1966
28 Plimer 2008.p 75
29 Plimer p42.
30 Lamb 1995

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