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The Climatic Stress Of The Fourteenth Century

In order to give concreteness to our picture of the climatic pulsations

of historic times let us take a specific period and see how its changes

of climate were distributed over the globe and how they are related to

the little changes which now take place in the sunspot cycle. We will

take the fourteenth century of the Christian era, especially the first

half. This period is chosen because it is the last and hence the best

/> known of the times when the climate of the earth seems to have taken a

considerable swing toward the conditions which now prevail when the sun

is most active, and which, if intensified, would apparently lead to

glaciation. It has already been discussed in World Power and

Evolution, but its importance and the fact that new evidence is

constantly coming to light warrant a fuller discussion.

To begin with Europe; according to the careful account of Pettersson[31]

the fourteenth century shows

a record of extreme climatic variations. In the cold winters the

rivers Rhine, Danube, Thames, and Po were frozen for weeks and

months. On these cold winters there followed violent floods, so that

the rivers mentioned inundated their valleys. Such floods are

recorded in 55 summers in the 14th century. There is, of course,

nothing astonishing in the fact that the inundations of the great

rivers of Europe were more devastating 600 to 700 years ago than in

our days, when the flow of the rivers has been regulated by canals,

locks, etc.; but still the inundations in the 13th and 14th

centuries must have surpassed everything of that kind which has

occurred since then. In 1342 the waters of the Rhine rose so high

that they inundated the city of Mayence and the Cathedral "usque ad

cingulum hominis." The walls of Cologne were flooded so that they

could be passed by boats in July. This occurred also in 1374 in the

midst of the month of February, which is of course an unusual season

for disasters of the kind. Again in other years the drought was so

intense that the same rivers, the Danube, Rhine, and others, nearly

dried up, and the Rhine could be forded at Cologne. This happened at

least twice in the same century. There is one exceptional summer of

such evil record that centuries afterwards it was spoken of as "the

old hot summer of 1357."

Pettersson goes on to speak of two oceanic phenomena on which the old

chronicles lay greater stress than on all others:

The first [is] the great storm-floods on the coast of the North Sea

and the Baltic, which occurred so frequently that not less than

nineteen floods of a destructiveness unparalleled in later times are

recorded from the 14th century. The coastline of the North Sea was

completely altered by these floods. Thus on January 16, 1300, half

of the island Heligoland and many other islands were engulfed by the

sea. The same fate overtook the island of Borkum, torn into several

islands by the storm-flood of January 16, which remoulded the

Frisian Islands into their present shape, when also Wendingstadt, on

the island of Sylt, and Thiryu parishes were engulfed. This flood is

known under the name of "the great man-drowning." The coasts of the

Baltic also were exposed to storm-floods of unparalleled violence.

On November 1, 1304, the island of Ruden was torn asunder from Rugen

by the force of the waves. Time does not allow me to dwell upon

individual disasters of this kind, but it will be well to note that

of the nineteen great floods on record eighteen occurred in the cold

season between the autumnal and vernal equinoxes.

The second remarkable phenomenon mentioned by the chronicles is the

freezing of the entire Baltic, which occurred many times during the

cold winters of these centuries. On such occasions it was possible

to travel with carriages over the ice from Sweden to Bornholm and

from Denmark to the German coast (Lubeck), and in some cases even

from Gotland to the coast of Estland.

Norlind[32] says that "the only authentic accounts" of the complete

freezing of the Baltic in the neighborhood of the Kattegat are in the

years 1296, 1306, 1323, and 1408. Of these 1296 is "much the most

uncertain," while 1323 was the coldest year ever recorded, as appears

from the fact that horses and sleighs crossed regularly from Sweden to

Germany on the ice.

Not only central Europe and the shores of the North Sea were marked by

climatic stress during the fourteenth century, but Scandinavia also

suffered. As Pettersson puts it:

On examining the historic (data) from the last centuries of the

Middle Ages, Dr. Bull of Christiania has come to the conclusion that

the decay of the Norwegian kingdom was not so much a consequence of

the political conditions at that time, as of the frequent failures

of the harvest so that corn [wheat] for bread had to be imported

from Luebeck, Rostock, Wismar and so forth. The Hansa Union undertook

the importation and obtained political power by its economic

influence. The Norwegian land-owners were forced to lower their

rents. The population decreased and became impoverished. The revenue

sank 60 to 70 per cent. Even the income from Church property

decreased. In 1367 corn was imported from Luebeck to a value of

one-half million kroner. The trade balance inclined to the

disadvantage of Norway whose sole article of export at that time

was dried fish. (The production of fish increased enormously in

the Baltic regions off south Sweden because of the same changes

which were influencing the lands, but this did not benefit

Norway.) Dr. Bull draws a comparison with the conditions described

in the Sagas when Nordland [at the Arctic Circle] produced enough

corn to feed the inhabitants of the country. At the time of

Asbjoern Selsbane the chieftains in Trondhenaes [still farther north

in latitude 69 deg.] grew so much corn that they did not need to go

southward to buy corn unless three successive years of dearth had

occurred. The province of Trondheim exported wheat to Iceland and

so forth. Probably the turbulent political state of Scandinavia at

the end of the Middle Ages was in a great measure due to

unfavorable climatic conditions, which lowered the standard of

life, and not entirely to misgovernment and political strife as

has hitherto been taken for granted.

During this same unfortunate first half of the fourteenth century

England also suffered from conditions which, if sufficiently

intensified, might be those of a glacial period. According to Thorwald

Rogers[33] the severest famine ever experienced in England was that of

1315-1316, and the next worst was in 1321. In fact, from 1308 to 1322

great scarcity of food prevailed most of the time. Other famines of less

severity occurred in 1351 and 1369. "The same cause was at work in all

these cases," says Rogers, "incessant rain, and cold, stormy summers. It

is said that the inclemency of the seasons affected the cattle, and that

numbers perished from disease and want." After the bad harvest of 1315

the price of wheat, which was already high, rose rapidly, and in May,

1316, was about five times the average. For a year or more thereafter it

remained at three or four times the ordinary level. The severity of the

famine may be judged from the fact that previous to the Great War the

most notable scarcity of wheat in modern England and the highest

relative price was in December, 1800. At that time wheat cost nearly

three times the usual amount, instead of five as in 1316. During the

famine of the early fourteenth century "it is said that people were

reduced to subsist upon roots, upon horses and dogs, and stories are

told of even more terrible acts by reason of the extreme famine." The

number of deaths was so great that the price of labor suffered a

permanent rise of at least 10 per cent. There simply were not people

enough left among the peasants to do the work demanded by the more

prosperous class who had not suffered so much.

After the famine came drought. The year 1325 appears to have been

peculiarly dry, and 1331, 1344, 1362, 1374, and 1377 were also dry. In

general these conditions do little harm in England. They are of interest

chiefly as showing how excessive rain and drought are apt to succeed one


These facts regarding northern and central Europe during the fourteenth

century are particularly significant when compared with the conclusions

which we have drawn in Earth and Sun from the growth of trees in

Germany and from the distribution of storms. A careful study of all the

facts shows that we are dealing with two distinct types of phenomena. In

the first place, the climate of central Europe seems to have been

peculiarly continental during the fourteenth century. The winters were

so cold that the rivers froze, and the summers were so wet that there

were floods every other year or oftener. This seems to be merely an

intensification of the conditions which prevail at the present time

during periods of many sunspots, as indicated by the growth of trees at

Eberswalde in Germany and by the number of storms in winter as compared

with summer. The prevalence of droughts, especially in the spring, is

also not inconsistent with the existence of floods at other seasons, for

one of the chief characteristics of a continental climate is that the

variations from one season to another are more marked than in oceanic

climates. Even the summer droughts are typically continental, for when

continental conditions prevail, the difference between the same season

in different years is extreme, as is well illustrated in Kansas. It must

always be remembered that what causes famine is not so much absolute

dryness as a temporary diminution of the rainfall.

The second type of phenomena is peculiarly oceanic in character. It

consists of two parts, both of which are precisely what would be

expected if a highly continental climate prevailed over the land. In the

first place, at certain times the cold area of high pressure, which is

the predominating characteristic of a continent during the winter,

apparently spread out over the neighboring oceans. Under such conditions

an inland sea, such as the Baltic, would be frozen, so that horses could

cross the ice even in the Far West. In the second place, because of the

unusually high pressure over the continent, the barometric gradients

apparently became intensified. Hence at the margin of the continental

high-pressure area the winds were unusually strong and the storms of

corresponding severity. Some of these storms may have passed entirely

along oceanic tracks, while others invaded the borders of the land, and

gave rise to the floods and to the wearing away of the coast described

by Pettersson.

Turning now to the east of Europe, Brueckner's[34] study of the Caspian

Sea shows that that region as well as western Europe was subject to

great climatic vicissitudes in the first half of the fourteenth century.

In 1306-1307 the Caspian Sea, after rising rapidly for several years,

stood thirty-seven feet above the present level and it probably rose

still higher during the succeeding decades. At least it remained at a

high level, for Hamdulla, the Persian, tells us that in 1325 a place

called Aboskun was under water.[35]

Still further east the inland lake of Lop Nor also rose at about this

time. According to a Chinese account the Dragon Town on the shore of Lop

Nor was destroyed by a flood. From Himley's translation it appears that

the level of the lake rose so as to overwhelm the city completely. This

would necessitate the expansion of the lake to a point eighty miles east

of Lulan, and fully fifty from the present eastern end of the Kara

Koshun marsh. The water would have to rise nearly, or quite, to a strand

which is now clearly visible at a height of twelve feet above the modern

lake or marsh.

In India the fourteenth century was characterized by what appears to

have been the most disastrous drought in all history. Apparently the

decrease in rainfall here was as striking as the increase in other parts

of the world. No statistics are available but we are told that in the

great famine which began in 1344 even the Mogul emperor was unable to

obtain the necessaries of life for his household. No rain worth

mentioning fell for years. In some places the famine lasted three or

four years, and in some twelve, and entire cities were left without an

inhabitant. In a later famine, 1769-1770, which occurred in Bengal

shortly after the foundation of British rule in India, but while the

native officials were still in power, a third of the population, or ten

out of thirty millions, perished. The famine in the first half of the

fourteenth century seems to have been far worse. These Indian famines

were apparently due to weak summer monsoons caused presumably by the

failure of central Asia to warm up as much as usual. The heavier

snowfall, and the greater cloudiness of the summer there, which probably

accompanied increased storminess, may have been the reason.

The New World as well as the Old appears to have been in a state of

climatic stress during the first half of the fourteenth century.

According to Pettersson, Greenland furnishes an example of this. At

first the inhabitants of that northland were fairly prosperous and were

able to approach from Iceland without much hindrance from the ice. Today

the North Atlantic Ocean northeast of Iceland is full of drift ice much

of the time. The border of the ice varies from season to season, but in

general it extends westward from Iceland not far from the Arctic circle

and then follows the coast of Greenland southward to Cape Farewell at

the southern tip and around to the western side for fifty miles or more.

Except under exceptional circumstances a ship cannot approach the coast

until well northward on the comparatively ice-free west coast. In the

old Sagas, however, nothing is said of ice in this region. The route

from Iceland to Greenland is carefully described. In the earliest times

it went from Iceland a trifle north of west so as to approach the coast

of Greenland after as short an ocean passage as possible. Then it went

down the coast in a region where approach is now practically impossible

because of the ice. At that time this coast was icy close to the shore,

but there is no sign that navigation was rendered difficult as is now

the case. Today no navigator would think of keeping close inland. The

old route also went north of the island on which Cape Farewell is

located, although the narrow channel between the island and the mainland

is now so blocked with ice that no modern vessel has ever penetrated it.

By the thirteenth century, however, there appears to have been a change.

In the Kungaspegel or Kings' Mirror, written at that time, navigators

are warned not to make the east coast too soon on account of ice, but no

new route is recommended in the neighborhood of Cape Farewell or

elsewhere. Finally, however, at the end of the fourteenth century,

nearly 150 years after the Kungaspegel, the old sailing route was

abandoned, and ships from Iceland sailed directly southwest to avoid the

ice. As Pettersson says:

... At the end of the thirteenth and the beginning of the fourteenth

century the European civilization in Greenland was wiped out by an

invasion of the aboriginal population. The colonists in the

Vesterbygd were driven from their homes and probably migrated to

America leaving behind their cattle in the fields. So they were

found by Ivar Bardsson, steward to the Bishop of Gardar, in his

official journey thither in 1342.

The Eskimo invasion must not be regarded as a common raid. It was

the transmigration of a people, and like other big movements of this

kind [was] impelled by altered conditions of nature, in this case

the alterations of climate caused by [or which caused?] the advance

of the ice. For their hunting and fishing the Eskimos require an at

least partially open arctic sea. The seal, their principal prey,

cannot live where the surface of the sea is entirely frozen over.

The cause of the favorable conditions in the Viking-age was,

according to my hypothesis, that the ice then melted at a higher

latitude in the arctic seas.

The Eskimos then lived further north in Greenland and North America.

When the climate deteriorated and the sea which gave them their

living was closed by ice the Eskimos had to find a more suitable

neighborhood. This they found in the land colonized by the Norsemen

whom they attacked and finally annihilated.

Finally, far to the south in Yucatan the ancient Maya civilization made

its last flickering effort at about this time. Not much is known of this

but in earlier periods the history of the Mayas seems to have agreed

quite closely with the fluctuations in climate.[36] Among the Mayas, as

we have seen, relatively dry periods were the times of greatest


Let us turn now to Fig. 3 once more and compare the climatic conditions

of the fourteenth century with those of periods of increasing rainfall.

Southern England, Ireland, and Scandinavia, where the crops were ruined

by extensive rain and storms in summer, are places where storminess and

rainfall now increase when sunspots are numerous. Central Europe and the

coasts of the North Sea, where flood and drought alternated, are regions

which now have relatively less rain when sunspots increase than when

they diminish. However, as appears from the trees measured by Douglass,

the winters become more continental and hence cooler, thus corresponding

to the cold winters of the fourteenth century when people walked on the

ice from Scandinavia to Denmark. When such high pressure prevails in the

winter, the total rainfall is diminished, but nevertheless the storms

are more severe than usual, especially in the spring. In southeastern

Europe, the part of the area whence the Caspian derives its water,

appears to have less rainfall during times of increasing sunspots than

when sunspots are few, but in an equally large area to the south, where

the mountains are higher and the run-off of the rain is more rapid, the

reverse is the case. This seems to mean that a slight diminution in the

water poured in by the Volga would be more than compensated by the water

derived from Persia and from the Oxus and Jaxartes rivers, which in the

fourteenth century appear to have filled the Sea of Aral and overflowed

in a large stream to the Caspian. Still farther east in central Asia, so

far as the records go, most of the country receives more rain when

sunspots are many than when they are few, which would agree with what

happened when the Dragon Town was inundated. In India, on the contrary,

there is a large area where the rainfall diminishes at times of many

sunspots, thus agreeing with the terrible famine from which the Moguls

suffered so severely. In the western hemisphere, Greenland, Arizona, and

California are all parts of the area where the rain increases with many

sunspots, while Yucatan seems to lie in an area of the opposite type.

Thus all the evidence seems to show that at times of climatic stress,

such as the fourteenth century, the conditions are essentially the same

as those which now prevail at times of increasing sunspots.

As to the number of sunspots, there is little evidence previous to about

1750. Yet that little is both interesting and important. Although

sunspots have been observed with care in Europe only a little more than

three centuries, the Chinese have records which go back nearly to the

beginning of the Christian era. Of course the records are far from

perfect, for the work was done by individuals and not by any great

organization which continued the same methods from generation to

generation. The mere fact that a good observer happened to use his

smoked glass to advantage may cause a particular period to appear to

have an unusual number of spots. On the other hand, the fact that such

an observer finds spots at some times and not at others tends to give a

valuable check on his results, as does the comparison of one observer's

work with that of another. Hence, in spite of many and obvious defects,

most students of the problem agree that the Chinese record possesses

much value, and that for a thousand years or more it gives a fairly true

idea of the general aspect of the sun. In the Chinese records the years

with many spots fall in groups, as would be expected, and are sometimes

separated by long intervals. Certain centuries appear to have been

marked by unusual spottedness. The most conspicuous of these is the

fourteenth, when the years 1370 to 1385 were particularly noteworthy,

for spots large enough to be visible to the naked eye covered the sun

much of the time. Hence Wolf,[37] who has made an exhaustive study of

the matter, concludes that there was an absolute maximum of spots about

1372. While this date is avowedly open to question, the great abundance

of sunspots at that time makes it probable that it cannot be far wrong.

If this is so, it seems that the great climatic disturbances of which we

have seen evidence in the fourteenth century occurred at a time when

sunspots were increasing, or at least when solar activity was under some

profoundly disturbing influence. Thus the evidence seems to show not

merely that the climate of historic times has been subject to important

pulsations, but that those pulsations were magnifications of the little

climatic changes which now take place in sunspot cycles. The past and

the present are apparently a unit except as to the intensity of the



[Footnote 31: O. Pettersson: The connection between hydrographical and

meteorological phenomena; Quarterly Journal of the Royal Meteorological

Society, Vol. 38, pp. 174-175.]

[Footnote 32: A. Norlind: Einige Bemerkungen ueber das Klima der

historischen Zeit nebst einem Verzeichnis mittelaltlicher Witterungs

erscheinungen; Lunds Univ. Arsskrift, N. F., Vol. 10, 1914, 53 pp.]

[Footnote 33: Thorwald Rogers: A History of Agriculture and Prices in


[Footnote 34: E. Brueckner: Klimaschwankungen seit 1700, Vienna, 1891.]

[Footnote 35: For a full discussion of the changes in the Caspian Sea,

see The Pulse of Asia, pp. 329-358.]

[Footnote 36: S. Q. Morley: The Inscriptions at Copan; Carnegie Inst. of

Wash., No. 219, 1920.

Ellsworth Huntington: The Red Man's Continent, 1919.]

[Footnote 37: See summary of Wolf's work with additional information by

H. Fritz; Zuerich Vierteljahrschrift, Vol. 38, 1893, pp. 77-107.]