HUMANPAST.NET

Environment                  30,000 BC
Africa
Southwest Asia
Egypt
Indus Valley
China
Europe
South America
Mesoamerica
North America
Other

In General

What is now clear is that during the last ice age, and the period that followed it, the climate was much more chaotic than it has been in recent millennia. Generally, the climate was much more variable. Sudden changes occurred from time to time. Collapse of parts of the ice sheets, or release of meltwater lakes that built up behind the ice, led to cataclysmic changes. Armadas of icebergs or floods of icy freshwater swept out into the North Atlantic altering the circulation of the ocean at a stroke and with it the climate of the neighbouring continents. With a flick of the climatic switch, Europe and much of North America could be plunged back into icy conditions, having only just emerged from the abyss of the preceding millennia. Conversely, the stability of the glacial conditions could be interrupted by a re-establishment of the flow of warm water to higher latitudes in the North Atlantic, bringing surprising temporary warmth to the northern continents. (145)

...the isotopic temperature records show some 20 interstadials, ...between 15 and 100 kya. Typically the events start with an abrupt warming of Greenland of some 5 to 10°C over a few decades or less. This warming is followed by a gradual cooling over several hundred years, and occasionally much longer. This cooling phase often ends with an abrupt final reduction of temperature back to cold ('stadial') conditions. (145)

The truly notable feature is the additional emphasis given to the prolonged cold period from 70 to 63 kya, to the cold spell at around 36 kya and to the frequency of extreme cold from 30 to 15 kya. (145)

Changes in the sea level during the last 100 kyr. (145)

 

Africa

 

Southwest Asia

 In Israel a detailed lake-level history of the closed Lake Lisan (part of the ancient Dead Sea) indicates that for much of the period from 55 kya to the end of the ice age the level was higher than at present. There were, however, catastrophic droughts associated with the Heinrich events. The impression is that cold-water input to the Mediterranean originating in the collapse of North Atlantic Deep Water formation caused a reduction of evaporation and less precipitation in the Levant. So it is reasonable to conclude that following Heinrich events 6, 5, and 3 much of the Middle East was desert. During these intervals, of which the long cold period from around 67 to 59 kya was the most significant, the region was largely uninhabitable for modern humans. (145)

Egypt

 A wet climate began in North Africa 50,000 years ago and lasted for 20,000 years. Called the Mousterian Pluvial, this wet era allowed the Sahara to bloom with plants and wildlife, but also with new human settlements. (70)

Indus Valley

 

China

 

Europe

Between about 30,000 and 10,000 years ago, European climates began a long cooling trend with some periods of extreme cold, but for most of the period the summers were cool and the winters relatively mild. The rich European grasslands and mixed forest habitats supported great numbers of herbivores, including reindeer, deer, bison, wild ox, ibex, woolly rhinoceros, and mammoths. France seems to have been densely occupied during this period, particularly near the confluence of the Dordogne and Vezere rivers. This lovely part of the world is a well-watered, heavily forested limestone formation, honeycombed with caves and rock shelters, which offered excellent places to live.

The warmth was such that it enabled humans to occupy parts of Siberia as far north as the Arctic Circle on the banks of the Usa River, close to the Ural Mountains, nearly 40 kya, and this occupation appears to have extended to the Yana River valley within 2000 km of the Bering Straits by 30 kya. As with much of Siberia, there was a maximum in forest development across Beringia between around 33 and 39 kya. In general, in the east of the region vegetation showed less propensity to swing between stadial and interstadial conditions, whereas near­interglacial forests alternated with more glacial-like tundra in western Beringia. The 'flickering' of the interstadial forests suggests great climatic variability in the west, in contrast to the more stable climatic regime farther east. (145)

South America

 Ironically, the site with perhaps the best claim to a pre-12,000 BP date date in the Americas is among the farthest south, Monte Verde, in south central Chile. Here Tom Dillehay and his crew have excavated a camp site that has been radiocarbon-dated to about 13,000 years ago, and below the levels of that age are layers of tools and debris that may be much older, perhaps up to 33,000 years old.(26)

The Monte Verde dates have recieved some support in the form of radiocarbon dates of hearths from sites near Pedra Furada, in eastern Brazil, where numerous stone tools and animal bones were found with charcoal in stratified layers that yielded a consistent series of twelve dates from about 32,000 to 17,000 years ago.(26)

We have two areas lying at similar distances from their respective poles. In one, the northern, we have many evidences of heavy glaciation, extending over a period of perhaps 40,000 years, but ending about 14,000 years ago, to give way to the present climate about 10,000 years ago. In Chile and Argentina, on the other hand, in the same relative latitude just as close, presumably, to a pole, we have no glaciation until after the climate has become normal for the present temperate zone in the north. It appears that in Argentina a cool period set in just as the hipsithermal phase with higher temperatures set in all over the northern hemisphere! Clearly, then, there was no similarity in climatic trends, but rather the opposite. (132)

Mesoamerica

 

North America

 Today, Eskimos using skin boats easily cross the ninety kilometers of open sea separating Siberia and America, and recently an American woman slathered herself with grease and actually swam from Alaska to Siberia. But such a sea crossing would not have been necessary during much of the Pleistocene. During periods of glacial advance within the last million years, enourmous quantities of water were converted to ice, lowering the sea level sufficiently to expose a 1500- to 3000-kilometer-wide expanse of the floor of the Bering Sea. This land bridge--usually referred to as Beringia--was probably available at least four times in the last 60,000 years.(25)

Prior to 10,000 years ago, species of deer, bison,camels, bears, foxes, mammoths, moose, caribou,and even rodents crossed from Siberia into the New World. Going in the other way--from America to Asia--were foxes, woodchucks, and, during the early Pliestocene, the ancestors of modern forms of horses, wolves, and other animals.(25)

Interior Alaska and Canada were relatively rich environments in the mid-Wisconsin interglacial, and at times humans may have had a narrow but clear ice-free run all the way to South America during this period. Pollen cores from easternmost Beringia suggest that from 30,000 to 14,000 years ago, the time when most archeologists think the first Americans arrived, the "landscape of Beringia consisted of relatively bare polar desert or fell-field tundra, a rocky terrain sparsely vegetated by herbs and dwarf shrubs. This suggests that the late Wisconsin environment in this part of Beringia was as harsh as the modern high Arctic.(25)

Startling evidence has been found which shows mammoth and other great beasts from the last ice age were blasted with material that came from space. Eight tusks dating to some 35,000 years ago all show signs of having been peppered with meteorite fragments. The ancient remains come from Alaska, but researchers also have a Siberian bison skull with the same pockmarks. Scientists painted a picture of a calamitous event over North America that may have severely knocked back the populations of some species.

"We think that there was probably an impact which exploded in the air that sent these particles flying into the animals," said Richard Firestone from the Lawrence Berkeley National Laboratory. "In the case of the bison, we know that it survived the impact because there's new bone growth around these marks."  Raised, burnt surface rings trace the point of entry of high-velocity projectiles; and the punctures are on only one side, consistent with a blast coming from a single direction. Viewed under an electron microscope, the embedded fragments appear to have exploded inside the tusk and bone, say the researchers. Shards have cut little channels. The sunken pieces are also magnetic, and tests show them to have a high iron-nickel content, but to be depleted in titanium. The ratios of different types of atoms in the fragments meant it was most unlikely they had originated on Earth. (36)

Several lines of solid evidence suggest that during the last ice age the North Pole was located in or near Hudson Bay. ...the best guess for the site of the pole seems to be approximately 60 degrees North Latitude and 83 degrees West Longitude. The first line of evidence that the last North American ice cap was a polar ice cap is based on the shape, size, and peculiar geographical location of the ice sheet. (132)

Thus we are able to say that warm conditions in the Arctic Archipelago of Canada persisted for the entire duration of the Wisconsin glaciation, from 40,000 years ago down to the establishment of modern conditions. Yes, if the pole were in Hudson Bay, the Arctic should be warm. And the Arctic was warm. However, there is much more evidence. ...the Arctic Ocean was warm during most of the ice age, particularly from about 32,000 to about 18,000 years ago.
Temperate conditions had evidently prevailed in Antarctica in the not distant past. The sediment indicated that no fewer than three times during the Pleistocene Epoch a temperate climate had prevailed in the Ross Sea.(132)

We have two areas lying at similar distances from their respective poles. In one, the northern, we have many evidences of heavy glaciation, extending over a period of perhaps 40,000 years, but ending about 14,000 years ago, to give way to the present climate about 10,000 years ago. In Chile and Argentina, on the other hand, in the same relative latitude just as close, presumably, to a pole, we have no glaciation until after the climate has become normal for the present temperate zone in the north. It appears that in Argentina a cool period set in just as the hipsithermal phase with higher temperatures set in all over the northern hemisphere! Clearly, then, there was no similarity in climatic trends, but rather the opposite. (132)

Studies of stalagmites from a cave in southeastern Missouri show remarkably little variation after a marked cooling around 55 kya. Prior to this, conditions appear to have oscillated more frequently. The warmest temperatures occurred around 57 kya and there were short-lived cooling events around 64, 71 and 74 kya. Beetle assemblages suggest that, following the cooling around 55 kya, the mean July temperature was 7.5-8°C lower than present and mean January value was 15-18°C lower than present. During what is termed the 'mid-Wisconsin' interstadial, dating from 43.5 to 39 kya, there was a rapid and intense warming. At the peak of this event, about 42kya, July temperatures were only 1-2°C lower than modern. (145)

Even more interesting is the question of whether Beringia effectively represented a refuge during the LGM. Analysis of beetle assemblages provides interesting insights into the climate during the ice age. At times temperatures in the region were relatively high. The Stage Three evidence suggested that at times northeast Siberia and Alaska were surprisingly mild. During the interstadials of Stage Three the region had temperatures that appear to have been comparable with modern times. Even as late as 30 to 25 kya parts of northeastern Siberia experienced summertime temperatures close to modern values. This relative warmth appears to have continued into the LGM. At the time, unlike the North Atlantic, the northern Pacific and the Gulf of Alaska were largely free of sea ice. This would have led to maritime cloud cover spreading over the extensive plains between what is now Chukotka and Alaska. The climate would have been colder than now in summer but relatively mild in winter. Combined with the extensive megafauna of the region, this may have made parts of the region habitable during the LGM. (145)

Other

 Farther east, there is evidence that modern humans had lived in Japan from about 30 kya, based on dating their flint tools. All four main Japanese islands were connected, and the southern island of Kyushu was connected to the Korean peninsula while the northern island of Hokkaido was linked to Siberia. These people appear to have survived the ice age and then around 12 kya developed a unique culture, which lasted for several thousand years. Their culture is known as 'Jomon', which means 'cord pattern', to describe the design of the pottery that these people produced - the earliest in human history. What is remarkable is that the Jomon were still a hunting, gathering and fishing society, living in small groups, when they developed this advanced technology. Furthermore, they also fashioned ceramic figurines. (145)