Human technology

Can archeology be used to study the effects of climate change?


Archaeological records provide an excellent opportunity to study how human societies have responded to climate change in the past, according to a recent review article in PNAS newspaper.

The past 50 years or so have witnessed tremendous developments in the field of climate modeling, which provides a backdrop to the natural records studied by archaeologists, ecologists and Earth scientists.

A classic example is a project called MIS3 which applied climate models to archaeological deposits and climate records (in the form of pollens, ice cores, fossils, etc.) from 25,000 to 29,000 years ago to understand why Neanderthals became extinct during the Ice Age and why only Homo sapiens survived.

But previous corroborations between archaeological and / or fossil records and climate models have posed major problems. For example, Earth scientists or archaeologists have little ability to control natural records. Some environments, such as acidic soils, are not at all conducive to preservation, making natural archives sparse and fragmented.

Much of these hurdles have been overcome in the recent past, with archaeologists relying heavily on remote sensing to examine anthropogenic impacts on the landscape, or advances in radiogenic isotope dating techniques, or even the use of isotopes. stable oxygen and carbon in biological remains.

Additionally, the development of sampling techniques for sediment cores and speleothems has provided us with earlier records of temperature, precipitation, and sea ice with high temporal resolution, albeit on a regional if not global scale.

Indeed, scientists working on direct assessments of past climate change using natural archives (pollen, mollusks, plant remains, fossilized bones; also called proxies) and climate modelers have everything to gain from one of the other.

While modelers benefit from the data provided by these proxies, helping them develop better models, archaeologists and Earth scientists, in turn, are relying on high-resolution models to gain context for climate change. that they see in the archaeological archives.

However, despite archeology’s ability to contribute to climate science, for much of the twentieth century, many archaeologists did not approve of archeology’s engagement in human-environment relationships.

Even today, although there have been technical advancements and more and more regions of the world continue to be explored by archaeologists and Earth scientists, high temporal resolution paleoclimatic proxies are rare.

Often, data from one region is extrapolated to others. For example, as many recordings are available for the Mediterranean region of Europe, but not so much for the loess regions of northern Europe, the former have been shown over regions much larger than those from which they originated. .

A similar challenge is also presented by ice cores. The study points out that it is not clear whether the polar ice core records can be good baseline data for, say, people living in mid-latitudes. Archaeological data, therefore, the authors point out, could fill a major gap here, as it targets regional-scale data on human settlements on a global scale.

In 1993, a study of a third millennial agricultural rain colony in northern Mesopotamia – what is today the Habur plains of Syria – used archaeological and soil-sediment (soil sediment) data and concluded that the site and surrounding areas have been abandoned due to increased aridity.

So what does “climate change archeology” as the authors call it tell us?

Environmental stress often forces societies to reorganize in different ways in different regions, highlighting the importance of cultural diversity.

In Southwest Asia, for example, the transition to sedentary agriculture did not occur simultaneously during the last glacial / interglacial cycle. The economic and cultural experiments have been considerable and the lack of a homogeneous response to climate change has made society more resilient.

Likewise, archaeological studies have shown how agricultural systems in the southern hemisphere have adapted to difficult-to-predict El Niño events.

The ancestors of today’s Cree people (an indigenous people of North America) “showed a clear preference for topographically stable locations, where the impacts of landscape transformations due to climate change were mitigated.”

However, in arctic regions, the patterns of sea ice formation are unpredictable. This topographical uncertainty makes it difficult for the Inuit to fall back on predetermined “ancestral trails”.

A key point of the study is that human societies navigate climate change differently, and not all societies succeed, let alone so successfully.

Archaeological research into past interactions between humans and the environment helps identify “social and ecological tipping points” that force societies to reorganize in different ways.

Ultimately, the study says, archaeological data sets have immense potential to inform current dialogues on resilience, including food security, and “can be used to promote community-based adaptation.”

Arian Burke, the study’s lead author, said in an interview: “One of the things we are learning is the importance of cultural diversity – both in the past and in the present – for the long-term survival of our species. “