New documentation of dramatic climate change at the end of the last ice age sheds light on the transition from nomadic hunter-gatherer societies to permanent residents and farmers • Plant remains helped researchers recreate climate at that time • Researchers:
A new study led by Tel Aviv University and Tel Hai Academic College reveals for the first time in high detail the climate that existed in the Land of Israel at the end of the last ice age about 20-10 thousand years before our time, based on identifications of plant remains. According to the researchers, the significant climate changes that characterized the period, and which were reflected in sharp differences in temperatures and the distribution of precipitation throughout the year, constituted a significant tier that influenced the transition from nomadic hunter-gatherers to permanent settlement and the agricultural lifestyle. In addition, the study provides, for the first time, information regarding the history of the region’s vegetation and its response to past climate change. Against the background of the discussions at the Glasgow conference, the researchers believe that understanding the response of the region’s vegetation to dramatic climate changes that have occurred in the past may help preserve the diversity of plant species in our region and assess the current and future climate challenges.
The study was carried out at the “Jordan Stairs” archeological site, located on the shores of the ancient Hula Lake. The uniqueness of the site is that in the strata of the site exceptional conservation conditions were created from which one can also learn about the activities of the ancient locals, who were mainly engaged in fishing, and can identify the plants that grew in those years (20-10 thousand years before) in the Hula Valley and its surroundings.
The study was conducted by Dr. Daphne Langot of the Department of Archeology and the Steinhardt Museum of Nature at Tel Aviv University, Prof. Gonen Sharon, Head of the Master’s Program in Galilee Studies at Tel Hai Academic College and Dr. Rashid Shadadi, an expert in evolution and ancient climate, at the University of Montpellier in France (Universite de Montpellier, CNRS-UM-IRD). The groundbreaking study was recently published in the leading journal Quaternary Science Reviews.
During this time, two major processes in world history took place: the transition from groups of nomads to permanent residents that took place during a period of dramatic climate change. Prof. Sharon, director of excavations at the Jordan Stairs site, explains: “In prehistoric research, this period is called the Epipaleolithic period. At the beginning of the period, people are organized in small groups of hunter-gatherers who roam the area. Then, around 15,000 years ago, “The emergence of permanent settlement in the villages, and other dramatic processes that culminate in the next period – the Neolithic, in which the most significant change in human history takes place – the transition to an agricultural life that shaped the world as we know it today.”
Dr. Langot, an archaeologist-botanist who specializes in identifying plant remains, adds that the second dramatic process in this period is the climatic changes that are taking place in our region. In the world, however, climatic conditions were different from those of today, the exact characteristics of which were not clear until this study. The climatic model we built based on reconstruction in plant species spreading fluctuations indicates that most of the climate change in our areas was reflected in a drop in temperature (up to 5 degrees Celsius less to the right), while precipitation amounts were similar today (less than 50 mm from the annual average).
However, Dr. Langot explains that later in the Apipolar period, 5,000 years later (about 15,000 years before our time), the model showed a significant improvement in climatic conditions. During this period, the first sites belonging to the Natopian culture appear in our area and it is very possible that the favorable climate helped the development and prosperity of this culture, in which permanent settlements, stone buildings, food storage facilities and more appear for the first time in the global arena.
Climatic instability and temperature drop
The next stage in the study deals with the end of the Epipleolithic period, about 12-11 thousand years ago, known as the Younger Drayas. This is a period of return to a cold and dry climate like the ice age, which is causing a kind of climate crisis all over the world. According to the researchers, until this study it was not clear whether there was an expression of this period in our area and to what extent.
According to the researchers: “The findings from the model presented in the article show that the period was characterized by climatic instability, high volatility and significant drop in temperatures. However, a surprising phenomenon was observed in the restoration of precipitation. This year, including summer rains.”
According to the researchers, such dispersal helped the expansion and prosperity of annual and herbaceous plant species. The gatherers who lived during this period now faced a wide and available variety of plants that could be collected throughout the year. This variety allowed them a deep acquaintance with the plants, just before they were domesticated. The researchers believe that these findings contribute to a new understanding of the environmental changes on the eve of the transition to agriculture and animal husbandry.
Dr. Langout concludes: “This research contributes not only to understanding the environmental background to fateful processes in human history such as the beginning of permanent settlement and the transition to agriculture, but also provides information regarding the region’s vegetation history and response to past climate change. There is no doubt that this information may help conserve species diversity and assess current and future climate challenges.”