HUMANPAST.NET

Environment                  5,000 BC
Africa
Southwest Asia
Egypt
Indus Valley
China
Europe
South America
Mesoamerica
North America
Other

In General

During the same 10,000-year epoch in which the ice melted and global sea-level rose by 120 metres - roughly from 17,000 down to 7000 years ago - our planet also experienced dramatically increased volcanism, dramatically increased frequency and magnitude of earthquakes, and a dramatically unstable climate that seesawed rapidly and unpredictably between extremes. (124)

Africa

 Rock art dating to 5000 BC corroborates what the radar equipment revealed. In Libya, Egypt, and Mali, petroglyphs depict not only grazing animals, but also aquatic life such as crocodiles. This indicates that the desert was inhabited during a time prior to 4000 BC and as far back as 8000 BC, when the climate was wet. (70)

The climatic record is, however, unequivocal: for most of the time between around 14 kya and 5 kya the Sahara experienced a monsoonal climate. The region had considerably greater rainfall than now and much of the land had permanent vegetation. (145)

Southwest Asia

Between about 5500 and 3500 B.C. Mesopotamian climates were comparatively humid, with a change to cooler and drier conditions after about 3500 BC. Subtle changes in climate like this might have had major effects on the settlement history of the area, because the zones in which dry-field rainfall-base grain cultivation was possible may have shifted. (46)

Between 13,000 BC and 4000 BC sea levels rose significantly as ice sheets melted. Meteorologists suggest that there was increased rainfall in the Near East in this era and botanists point to increased plant life. (68)

By 5000 BC a large marine estuary formed where the Euphrates River exists today. Then, over the next two millennia, the vast estuary filled in with silt. The water table remained high, however. As windblown dust drifted in from the Arabian Peninsula, sea levels stabilized and the silt and accumulating dust choked the estuaries so that large swampy areas formed. (68)

The steadily rising sea levels might have had a more profound effect on coastal communities where large areas were inundated in fits and starts. For example, this could have happened in the Persian Gulf. This enclosed sea goes no deeper than 100 m, and much of the seabed is only about 40 m below the present-day surface. When sea levels were 120 m lower the gulf would have been dry land 20 kya, and the ancestral river system of the Tigris and Euphrates flowed through the deepest part of the gulf, a canyon cut by the river waters to the Indian Ocean. The postglacial rise in sea level inundated the floor of the gulf between 15 and 6 kya. The sea advanced more than 1000 km, forcing any people living there to abandon their settlements. (145)

The climatic record is, however, unequivocal: for most of the time between around 14 kya and 5 kya the Sahara experienced a monsoonal climate. The region had considerably greater rainfall than now and much of the land had permanent vegetation. (145)

Covering an area of some 30000 km, the flat, river-made land of Sumer had no minerals, almost no stone and no trees. In summer the daytime maximum temperatures average around 40°C and often reach 5O°C. Annual rainfall is about 150mm and it is bone dry for eight months of the year. Winter nights are cold, and the strong north winds can bring squally rainstorms. In spring, the melting snows of the Taurus and Zagros mountains produce flash floods. In bad years, these swept everything before them. While the climate of the mid-Holocene may have been moister, these fundamental climatic challenges were part of the development of the region. Yet by around 5.8 kya as many as 10,000 people may have lived in the city of Uruk. (145)

...by about 8.5 kya, rising sea levels had covered much of the present-day northern Persian Gulf. A large estuary formed where the Euphrates River exists today. As the sea level rise slowed around 7 kya, the river estuaries receded from their northernmost limits, which extended along the Euphrates as far north as Ur. Then the estuary began to fill with silt, impeding the natural drainage and forming large swampy areas, and the climate became more arid. (145)

c. 5000-4000 BC A 'second' flood strikes the Mesopotamian plains in the form of a series of localized inundations. The memory of these events is confused with much earlier traditions concerning a deluge accompanying the cessation of the last Ice Age, c. 9500 - 9000 BC. They are remembered as the 'Flood of Noah' by the Yezidis of Kurdistan. (149)

Egypt

 The archaeologist Fred Wendorf calculated that there were three major eras of rain in the eastern Sahara prior to 2500 BC. According to Wendorf, evidence of these rainy eras is seen in the massive silt deposits that remain from seasonal playas, or temporary lakes, from which over one hundred radiocarbon dates have been obtained. These three episodes of high precipitation were separated by periods of extreme aridity from 5300 to 5100 BC and 4700 to 4500 BC, with the water table falling to the same (or lower) level at which it is today. During these intervening arid periods, playa silts were extensively eroded and, in some cases, sand dunes filled in the hollows of the drained lake basins. The megalithic structures and sandstone circles at Nabta Playa, in southern Egypt, were placed in sediments that had accumulated between 5000 and 4700 BC. (70)

As the climate grew more humid around 8000 BC, rainfall turned low-lying areas into lakes and playas. With the onset of this "Neolithic pluvial," the region we now know as Egypt became an extension of the Sahelian savanna. The area offered pastoralists and animals new habitable lands. According to Haynes, during that time, the area received a minimum of eleven inches of rainfall annually and possibly as much as twenty-four. Between 7000 and 4000 BC, when the leading edge of monsoon rains covered a significant portion of Africa's interior, a "pluvial maximum"--when rainfall was at its peak--developed, turning the desert green with life. (70)

Evidence from the Gilf Kebir region reflects a semiarid to arid climate that was dominated by hare, gazelle, and rodents. Remains discovered at Dahkla include hartebeest, gazelle, horse, hippopotamus, bovids, elephant, ostrich, and fish. Rhinoceros bones have been found at Merga, and elephant, antelope, wild cats, and giraffe at Abu Ballas. Since giraffes eat the leaves, buds, and twigs of acacia trees and other plants, it can be assumed that across the region sufficient trees were available to support their diet. (70)

Playas in the northern Egyptian oases were active until 5000 BC. In the Siwa Oasis, the Hatiet Urn El-Hiyus Playa was active through 5900 BC but began to dry out from its high point during the sixth millennium BC. The evidence from these playas indicates that between 8000 and 5000 BC the climate conditions alternated between arid, and wet. Although wet periods lasted for several hundred years, making the region habitable, the overall climate was mostly dry. (70)

Swamplike conditions existed between 6400 and 5000 BC in northern Sudan, with shallow lakes peppering the dunes west of the Nile Valley. Waterways, near Naga Hamra, Gebel Nageru, and Wadi Howar, supported a diversity of animals that included crocodile, hippopotamus, land tortoise, domesticated cattle, elephant, rhinoceros, warthog, giraffe, and several varieties of fish. Aquatic animal fossils, such as hippopotamus, crocodile, and fish, indicate that waterways existed, and that some were connected to the Nile. (70)

Several wadis flowed into the Nile, including the Wadi Howar, across north-central Sudan, and the Wadi Melik, which flowed from 5700 to 4000 BC. Humid conditions along the Nile Valley resulted in deposits of silt, mud, and gravel before 3000 BC. Nile flooding between 6200 and 4600 BC created high lake levels in El Faiyum, a province in Upper Egypt, and discharged a considerable amount of freshwater into the Mediterranean Sea. (70)

Fossil evidence from the Selima Sand Sheet, which was initially formed during the ice age, also suggests that a wet period occurred between 8000 and 5000 BC. (70)

Playas in the northern Egyptian oases dried up around 5000 BC and their basins filled in with windblown sand. The Hatiet Urn EI-Hiyus Playa, in the Siwa Oasis, was active through 5900 BC, but began to dry out from its high point during the sixth millennium BC. (70)

Investigations at Selima suggest that the lake endured intense evaporation between 5000 and 4000 BC, resulting in the formation of a saltwater lake around 4400 BC. Plant life, established in the region, persisted until 4000 BC. Isotopic measurements on mollusks indicate that dry conditions prevailed around 3600 BC. (70)

By 5000 BC, many rain-fed playas in Egypt had vanished. Most were significantly desiccated, due to drought, by 3500 BC, and plant life began to disappear as early as 5600 BC. After 3900 BC, many playa basins were literally filled with sand. At Nabta Playa alternating layers of forest and windblown sands indicate that arid periods interrupted more humid conditions between 5700 and 3800 BC. (70)

Egypt's Arba'in Desert and surrounding region has been arid, receiving less than half an inch of rain per year for the last fifteen thousand to twenty thousand years. However wetter conditions prevailed between 7000 and 4000 B.C.E., with rainwater averaging more than twelve inches per year and possibly as much as twenty-four. (70)

Rock art dating to 5000 BC corroborates what the radar equipment revealed. In Libya, Egypt, and Mali, petroglyphs depict not only grazing animals, but also aquatic life such as crocodiles. This indicates that the desert was inhabited during a time prior to 4000 BC and as far back as 8000 BC, when the climate was wet. (70)

…the most important settlements were probably always situated on the floodplain of the Nile; if the floodplain was indeed lower between 8000 and 5000 BC, as has recently been suggested, sites of that period would now lie buried under more recent deposits of alluvium. It has never seemed logical that the Nile valley would be almost uninhabited during a period when lands to the east and west of Egypt were experiencing great advances in population and cultural development. (115)

The climatic record is, however, unequivocal: for most of the time between around 14 kya and 5 kya the Sahara experienced a monsoonal climate. The region had considerably greater rainfall than now and much of the land had permanent vegetation. (145)

Following the turbulent period of global upheavals and climatic changes that signalled the end of the last Ice Age, everything seems to have gone quiet in Egypt. All that is known from palaeo­climatological research is that between 8000 and 5000 BC the country suffered heavily from intensely long periods of rain - a time known to scholars as the neolithic subpluvial (a pluvial being a period of constant rain). Little is known about the peoples who inhabited Egypt during this age. (149)

Indus Valley

 The maps for 7700 years ago and 6900 years ago show that in this relatively short period of 800 years the large remnant island below the Gulf of Cambay was completely wiped off the map and the Gulf itself was fully and permanently inundated to its modern extent. For any hypothetical coastal culture that had been forced to retreat and compact into the Gulf's pleasant valley over the previous 6000 years, or that had lived on the island, it goes without saying that these events would have been more than cataclysmic. They would have looked like the end of the world. (124)

An epoch of spectacular geological turmoil occurred at the end of the last Ice Age, with the most dramatic effects registered in a series of cataclysmic floods that took place at intervals between roughly 15,000 and 7000 years ago. Is it an accident that this same 8000-year period has been pinpointed by archaeologists as the very one in which our supposedly primitive forefathers made the transition (in different places at somewhat different times) from their age-old hunter-gatherer lifestyle to settled agriculture? Or could there be more to 'the food-producing revolution' than meets the eye? After all, most scientists already recognize a causative connection between the end of the Ice Age and the supposed beginning of farming - indeed an unproven hypothesis that rapid climate changes forced hunter-gatherers to invent agriculture presently serves as pretty much the sum of conventional wisdom on this subject. But there is another possibility. Nobody seems to have noticed that in the general vicinity of each of the places in the world where the food-producing revolution is supposed to have begun between 15,000 and 7000 years ago there is also a large area of land that was submerged by the post-glacial floods between 15,000 and 7000 years ago: We have seen that this is true for India, one of the world's ancient agricultural 'hearths', which lost more than a million square kilometres in the south and the west and, most conspicuously in the north-west, at the end of the Ice Age. (124)

China

  …for some thousands of years after the end of the Pleistocene at about 12,000 years ago, China's climate was somewhat warmer and moister than it is today, and much of the country was probably heavily forested, from the temperate forests of the north to the jungles in the south. (49)

Widespread evidence of lake levels in China and Mongolia shows that conditions were moister than present until 5 kya. (145)

Europe

 In 1931 a trawler working in the southern North Sea dredged up a lump of peat containing an exquisitely crafted spearhead made from a deer's antler. Dated as being nearly 14 kyr old, this artefact was dramatic evidence of how early humans exploited the broad expanses of land that had been exposed during the last ice age, and were only reclaimed by the sea some 7 kya. When this spearhead was buried, dense oak forests had yet to spread into the region, known to archaeologists as 'Doggerland', where now the sea is over 30m deep. This famous find emphasises that the rise in sea level between about 15 and 5 kya covered up large areas of habitable land that had been exploited by humans and made movement around the continental margins easier. (145)

5500 BC Baltic sea flood (160)

4900 BC Skaill freshwater loch flooded by sea to become Skaill Bay (160)

South America

 Radiocarbon datings of materials from Tiahuanaco indicate the site is much younger than expected. The early classic style there is dated to about the fifth century BC, and the following cultural period to about the time of Christ. The city continued to be occupied as late as the eighth century AD. It would seem from these dates that the geological upheavals indicated in this chapter came very late. This is in agreement with the impression of Darwin, for example, that the uplift of the South American coast was very recent. (132)

Mesoamerica

 

North America

 By about 5,000 BC, the glaciers had retreated to the point that the flora and fauna of the eastern United States were very similar to what they are today--except where changed by human activity--and there was a broad cultural readaptation to the changing environments.(26)

In some prehistoric periods the Southwest was wetter than it is today, but for most of the last ten thousand years the Southwest has usually been at least as hot and dry as it is today, and there were short periods of extreme drought. (53)

A prominent ash layer at a depth corresponding to 4803 B.C. may have come from the eruption in Oregon that destroyed Mount Mazama, leaving the giant caldera that is now Crater Lake. (89)

During the Clovis era, which began 11,500 years ago and continued for a few hundred years thereafter, the living things of North America were undergoing what was one of the more traumatic times in the history of the earth. For people living here at the time, the world may well have seemed an unstable place. Familiar animals might suddenly disappear, seeking their favored food, which had also gone somewhere else. What might have been a good place for your parents might change into something that would not support you. People would have been on the move. One result was a great many more species going extinct, not unlike what had happened in all the previous interstadials. These ecological changes were driven, of course, by the relatively rapid climate change that brought on the relatively rapid disintegration of the glacial ice: by 7,000 years ago, the ice was about what it is today in extent and location. The particularly important results of the overall climate change under way were the reestablishment of four-season continental climates and the increase in seasonal extremes - colder winters, hotter summers - which unquestionably stressed the creatures that had adapted to somewhat more consistent year-round conditions. There's only so much cold a southern white pine can take, for example, and only so much summer heat a blue spruce can live through. In this chaotic late Pleistocene-early Holocene period, the limits of everyone and everything were being tested. Creatures needed to readjust to new ranges. Among mammals, size transformation proved a more salutary strategy than the conservative one of simply sweating it out: the 350-pound beaver gave way to a successor more like today's, for example, smaller in size and behaviorally more clever. Changing patterns of precipitation (and evaporation) would have created similar challenges. New habitats were being created in virtually every part of North America, a shifting kaleidoscope of ecosystems that meant tremendous change for any creatures present, including humans.(130)

Other

 …until as recently as 6000 years ago, as I was to discover when I received Glenn Milne's inundation maps for the region in the summer of 2001, Bimini remained part of a large antediluvian island lying across the Gulf Stream from Florida. Very close to the north-western tip of this palaeo-island, overlooking the Gulf Stream then as they do today, were what is now Paradise Point and the present site of the Bimini Road. (124)

The inundation map for 12,400 years ago shows, to the north, a crescent-shaped island around present-day Grand Bahama, Great Abaco and Little Abaco. Clockwise to the south-east from there we come to a second lost island. This island fills in what is now Tarpum Bay under Eleuthera, then connects via the thin but very probably unbroken line of the Exuma Cays to an even larger exposed area stretching almost as far south as Cuba - itself significantly larger than it is today. Third, to the north-west in the direction of the Florida peninsula covering present-day Andros island and occupying most of the Great Bahama Bank, is the largest antediluvian island of all, with Bimini and the Bimini Road right at its tip.

The inundation map for 6900 years ago shows some coastal erosion of the three main islands but otherwise the picture remains basically unchanged - indicating that the islands survived beyond the last of the three great episodes of global postglacial flooding around 7000 years ago.

However, in the next inundation map in the sequence, for 4800 years ago, all the islands have gone. The most likely culprit for their inundation is the so-called Flandrian transgression, the final spasm of the Ice Age meltdown, which took place between 6000 and 5000 years ago. (124)

Some 260 million years ago, during the Permian period, deciduous trees adapted to a warm climate grew in Antarctica. ...Here at the southernmost known mountain in the world, - scarcely two hundred miles from the South Pole, was found conclusive evidence that the climate of Antarctica was once temperate or even sub-tropical. ...sedimentary cores collected from the bottom of the Ross Sea by one of the Byrd Antarctic Expeditions provide conclusive evidence that 'great rivers, carrying down fine well grained sediments' did flow in this part of Antarctica until perhaps as late as 4000 BC. From 6000 to 15,000 years ago the sediment is fine-grained with the exception of one granule at about 12,000 years ago. This suggests an absence of ice from the area during that period, except perhaps for a stray iceberg 12,000 years ago. ...at one time the temperatures of the Arctic Ocean were similar to the contemporary temperatures of the Bay of Bengal or the Caribbean Sea. (152)