How did they survive? New research shows Jordanian city survived climate change disaster 4,200 years ago

4,200 years ago Tall el-Hammam survived a climate change disaster that
decimated civilizations throughout the Middle East.

A map of Tall el-Hammam, archaeologists believe that an abundence of
water resources helped this city survive the arid conditions that hit the
Middle East 4,200 years ago.

Evidence suggests that, as the climate grew arid, there was an
increasing number of nomadic groups in the Levant.  This gate at
Tall el-Hammam was blocked off about 4,200 years ago,
likely in an attempt to keep them out of the city.

(4) Shows the blockage, (1) and (2) show the passageway walls of the gateway
(6) shows the walking surface as it was 5,000 years ago. (3) shows the
surface as it was 4,500 years ago and (5) shows fill that was put in
to level the gateway with the ground 4,500 years ago.

It's estimated that nearly 1,000 dolmens existed at Tall el-Hammam.
Archaeologists believe that they were used in ancestor worship.

NOTE - All photos and maps courtesy Tall el-Hammam Excavation Project

About 4,200 years ago a series of disasters struck cities and civilizations throughout the Middle East.

In Egypt the central government collapsed. The same state that had built the great pyramids, and kept pharaoh as the supreme authority, could no longer keep the country united. This ushered in an era of powerful provincial leaders (known as nomarchs) and rival claimants to the Egyptian throne.

A similar scenario happened in Mesopotamia where the Akkadian Empire, an entity whose power stretched from the Persian Gulf to the Mediterranean, also went under. This led to local rulers stepping in and taking up power. 

There is also evidence of social upheaval in the Levant. The city of Khirbet ez-Zeiraqoun in northern Jordan, whose inhabitants burrowed out hundreds of meters of water tunnels into the ground, was abandoned.

Climate change is believed to be a major reason for this upheaval. Research in the Middle East suggests that the environment became increasingly arid – making it difficult to support the intensive farming that is required to feed large cities.

“Paleoclimactic data from numerous sites, document changes in the Mediterranean westerlies and monsoon rainfall during this event with precipitation reductions of up to 30%, that diminished agricultural production from the Aegean to the Indus,” wrote scientists Harvey Weiss and Raymond Bradley in a paper they published.

“What that climate change is a result of is a mystery,” said Professor Steven Collins, of Trinity Southwest University. “There are even folks speculating on some sort of cosmic impact event like an asteroid strike at some point on the globe that created some sort of climatological disaster for the whole planet, not just for the Middle East.”

Together with Khalil Hamdan, of Jordan’s Department of Antiquities, Collins leads archaeological work at the Jordanian city of Tall el-Hammam. Located in the southern Jordan Valley, new research at this 36 hectare city shows that, remarkably, it continued to operate during this climate shift. “It was not only around it was thriving,” Collins said.  

An ancient metropolis

Archaeological work shows that people were living at Tall el-Hammam at least as far back as 6,000 years ago.

By the time the climate disaster hit, nearly 4,200 years ago, the city supported a population of between 15,000 to 25,000 people living in or nearby.

The team believes that it was the centre of a small kingdom ruled by a king. The city certainly had its share of amenities. A 100 meter by 100 meter raised platform served as the main hub of the city, containing temples and administrative buildings.

The city was protected by a massive fortification system with walls that Collins said were “about six meters thick and would have been about three times that high.” These fortifications had somewhere between 15 and 20 gates, giving outsiders access to the settlement.  

Domestic residences in the city were modest. Built of mud brick, they had stone foundations and walls that were half a meter thick. Archaeological work suggests that these houses were reused and modified over a vast amount of time. One residence the team found was used from between 4,600 and 3,600 years ago, with modifications being made occasionally.

One of the most enigmatic features of the city was its dolmen field. In ancient times the people of Tall el-Hammam built nearly 1,000 of these stone monuments. “They go up into the hills surrounding the east and south of the city state,” said Collins.

Many of the dolmens have either been destroyed or looted but the team has found a few intact examples. From the excavation of them “we pretty much concluded that they’re not primary burials, and they’re probably not even secondary burials,” said Collins. Rather “they seem to be memorial monuments related to some sort of ancestor worship.”

What may have taken place is that on certain days people would have opened the grave of an ancestor, taken a bone out and had it “ritually placed (near the dolmen) with some sort of small offering like a juglet of wine, or a juglet of oil, or a bowl of some sort of offering.”

Climate change survivor

All together the picture the evidence paints is that Tall el-Hammam was a thriving place when it entered the climate catastrophe. “It’s very dramatic and it’s obviously a very long enduring powerful city state,” said Collins.

When the climate changed, about 4,200 years ago, many of the cities and civilizations in the Middle East were wiped out. The increased aridity made it hard for them to grow crops and keep up an urban way of life.

“As a result the large majority of the cities in the Levant, particularly the southern Levant, completely went out of business,” said Collins.

But the people did not go away. As agriculture became untenable in many areas people became nomads, turning to pastoralism as a way to survive. It was a “period of extreme social upheaval in the region, there would have been a lot of nomads and semi-nomads ranging about, threatening cities, especially cities that were wealthy and thriving.”

Among those few cities still surviving was Tall el-Hammam. The team’s research reveals that the defences of the city were bolstered – with many of the city’s gates being blocked off, probably in an effort to keep those nomads out.

The effort seems to have helped, at least on some level. The city continued to be occupied throughout this period of climate collapse. Collins said that the team needs to do more excavation to get a complete sense of how the city was affected but so far the findings show that the houses were occupied “pretty much throughout (the) interruption.”

All in all “my gut feeling now is that the city footprint – residences, temples, administrative buildings, palaces – didn’t change appreciably or maybe even at all.”

Why did it survive?

This discovery raises an important question – why did it survive? Blocking off the entrances alone would not have done it. While that would have helped prevent nomads from getting in, it would not have helped the residents grow food.

Collins believes that access to water is the reason why the city survived. Unlike many areas in the Middle East, the people at Tall el-Hammam had it in abundance and coming from multiple sources.

“It really boils down to the water resources,” said Collins.

“You have the Jordan river which, even in the worst case scenario, never would have dried up.” Also “you have two perennial rivers one (on) the north, one on the south, that would have continued to flow most of the time, even in a very dry climate regime.” In addition a number of springs, fed by groundwater, also would have brought in water.

One other factor is the temperature in the southern Jordan Valley. Not only did people have access to a good amount of water but they also had the ability to grow crops year-round.

“With the right water resources you can grow several crops a year,” said Collins. “It might be snowing and freezing up in Amman or up in Jerusalem but down in the valley it will be 60, 70 or 80 degree (Fahrenheit).”

So what lesson can we take away from this? Like people 4,200 years ago our civilization is facing a period of climate change (although this time induced by humans). Is there something that the experience of this ancient city can teach us?

“The lesson is to be smart about the utilization of water resources,” said Collins. “People need to do what Tall el-Hammam did and very carefully manage their water resources so they can survive.”