Looking Ahead to the Past: Archeological Evidence Suggests Potential Solutions to Looming Climactic Challenges

Above Image: Ruins of Adummatu in northern Saudi Arabia. Source: Wikipedia.

Article: Petraglia, MD, Groucutt, HS, Guagnin, M, Breeze, PS, & Boivin, N. (2020). Human responses to climate and ecosystem change in ancient Arabia. Proceedings of the National Academy of Sciences, 117(15), 8263-8270. https://doi.org/10.1073/pnas.1920211117

Background

Global warming is here.

It’s not a single action or a time-limited even, like so-called once-in-a-century bad storms. It’s a long process whose acceleration over the last decades has increased the pace and potential scope of resultant global climate change.

Climate change is much more than mere global warming; it includes changes in temperature, precipitation, storm severity, winds, sea level, and many other factors.

Such changes in climate have happened multiple times over many thousands of years of human history. For example, climate dramatically changed following the impact of the asteroid that killed the dinosaurs. Specifically, after the impact the Earth’s skies were covered with a massive sulfur cloud which led to a steady cooling of the planet. However, unlike than the largely natural origins of previous episodes, the current episode of climate change is greatly influenced by human activity. This has resulted in faster rates of change than previous episodes.

To learn more about how the previous periods of climate change affected humans, scientists are studying archeological findings and the environment of past millennia. In this way, we can find clues about how our ancestors survived major changes in climate. An article by Michael D. Petraglia and colleagues recently published in the Proceedings of the National Academy of Sciences examined archeological, paleo-environmental, historical, and current data to paint a picture of how the people of ancient Arabia dealt with drastic climatic changes.

Article Overview

Arabia refers largely to the Arabian Peninsula. This area is made up of today’s nations of Saudi Arabia, Yemen, Oman, United Arab Emirates, Qatar, Kuwait, and parts of Jordan and Iraq. Humans have lived in various areas of the peninsula continuously for thousands of years. Today its chief economic activity centers on petroleum extraction and refining, and it is one of the warmest and driest areas of the planet. Most areas of the peninsula see significant amounts of surface water only occasionally, as Figure 1 from the article shows (below).

Figure 1 from Petraglia et al, 2020 showing availability of water in the Arabian Peninsula from 1984-2015. The colored dots represent the frequency of water availability in each location as per the key in the bottom right of the figure.

However, in the past, temperatures were much lower and precipitation was much higher. This created a very fertile area that saw widespread agriculture and civilizations centered around several established cities (shown in Figure 1).
That abundant fertility did not last, because rainfall drastically lessened. Current archeological and paleo-environmental evidence shows that a series of prolonged droughts lasting several years to several decades occurred between 11,000 and 4,000 years ago. These droughts profoundly altered the population patterns of the peninsula, as shown in Figure 2 from the article, below.

Figure 2 from Petraglia et al, 2020. The vertical brown shaded bars show the periods of drought. Panel A shows population levels in the Gulf Coast region, Panel B shows population levels in the interior of the peninsula, and Panel C shows the presence of human populations in Northern Arabia (which each numbered row corresponding to a different archeologic site). ka = thousands of years.

After the earliest periods of drought (rightmost shaded bars in panels A and B), people moved from the interior parts of the region to the coast, as shown by decreased population in the interior and increased population in the coast. This would have allowed them to supplement their diet with fish and other food sources on the coast. However, after later periods of drought, populations in both the interior and coastal regions increased, which suggests that during these times, people did not move to new, empty areas. Rather, they moved to areas that were already established settlements and still had reliable water sources).

This concentrated the population and likely lead to competition and conflict. Indeed, the authors discuss archeological remains from these periods that show increased evidence of bodily injury and violent deaths, suggesting fighting among larger populations over scarce resources like food and water.

Eerily, after the most recent drought, which lasted several centuries, there is a drastic reduction in population in both the coast and the interior. This suggests that a large number of people died during that drought period. Several sites show evidence of human population before that drought (panel C), but only one (site 5) shows (greatly reduced) evidence of human population after that drought. Since that same time period shows far lower population in both the coast and the interior, this is not a question of people moving from many different areas into one area. Instead, this is further evidence of a population-level mass death.

These droughts did not affect only population distributions and numbers. As shown in Figure 3 from the article below, the end of many cultures coincided with the start or the middle of drought periods. This means that these droughts ended civilizations and entire known ways of life. The cultures and civilizations that came after each period of drought seem to have started only after that particular drought period ended.

Figure 3 from Petraglia et al, 2020. BP = ‘before present”. Vertical shaded bars show periods of drought, as in previous figures. The horizontal bars show the times during which the labeled culture or civilization is known to have existed.

In all the areas of ancient Arabia studied by the researchers, humanity and civilization seem to have had to start over after these episodes of major climate change.

How Will We React to Climate Change

As the article points out, archeological evidence shows that climate change led of mass deaths, increased conflict and violence, large-scale population movements to coastal areas, and the end of several civilizations in ancient Arabia.

Who is to say that the current ongoing and ever-increasing climate change will be any different for us in today’s world than it was for the people of ancient Arabia?

Given that current climate change is a worldwide phenomenon, in a world with billions more people than ancient Arabia, and that today’s nations have vastly more destructive weapons, any resultant conflict could actually be far more destructive and deadly.

An Unclear Future and a Glimmer of Hope

We don’t know yet the full extent of the damage that this current period of climate change will cause, neither in Arabia nor around the world. We do know that drastic climatic changes have happened before. Their consequences ranged from mass movements of populations to areas more suitable for life, all the way to the very end of civilization as the people of that era knew it.

That said, all was and is not gloom and doom.

Though the population of ancient Arabia was reduced, shifted, and culturally greatly altered, the people endured. Those who survived, adapted, overcame, and eventually thrived in what had become largely a harsh desert area. The researchers discussed archeological evidence that shows new farming techniques – that used less water, or found new ways to make use of new sources of water, or both – that seem to have been developed after the most recent (and most destructive periods of drought). Also much more evident during this time was maritime activity like fishing and aquaculture. Many of these practices continue today, and governments in the area have taken steps to ensure that they are protected. This will allow those techniques to be studied, taught, and if necessary, refined for the reality of this period of climate change.

In all, archeologists have uncovered the adaptability of humans and shown that there is hope. Even then, the direct impacts of climate change we will face are not something to look forward to. But, as an individual there are certainly steps to take to prevent the worst, locally and globally.

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Munim Deen

Munim is an epidemiologist and cartographer. His primary interests are infectious disease outbreaks and their intersection with the environment, public policy, and society at large. A geographic information system (GIS) devotee, he incorporates mapping and spatial analysis into his work whenever possible. A former newspaper columnist, he holds a bachelor's degree in microbiology and a master's degree in epidemiology.

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