Plant remains have helped researchers reconstruct the climate in the Land of Israel at the end of the last ice age
A new study led by Tel Aviv University and Tel Hai Academic College reveals for the first time at a high level of detail the climate that existed in the Land of Israel at the end of the last Ice Age (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 layer that affected the transition from a nomadic hunter-gatherer society to permanent settlement and the agricultural lifestyle. In addition, the study provides, for the first time, information regarding the history of the area's vegetation and its response to climate changes in the past. 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 occurred in the past may help preserve the diversity of plant species in our regions and assess the current and future climate challenges.
The research was conducted by Dr. Dafna Langut from the Department of Archeology and the Steinhardt Museum of Nature at Tel Aviv University, Prof. Gonen Sharon, Head of the Master's Degree Program in Galilee Studies at Tel Hai Academic College and Dr. Rashid Shadadi, an expert on evolution and ancient climate, from the University Montpellier in France (Universite de Montpellier, CNRS-UM-IRD). The groundbreaking research was recently published in the leading journal Quaternary Science Reviews.
The research was carried out at the "Steps of the Jordan" archaeological site, located on the shore of the ancient Hula Lake. The uniqueness of the site is that extraordinary preservation conditions have been created in the layers of the site from which you can also learn about the activities of the ancient inhabitants of the place, who were mainly engaged in fishing, and you can also identify the plants that grew in those years (20-10 thousand years before our time) in the Hula Valley and its surroundings.
In this period of time, two major processes took place in world history: a transition from groups of nomads to permanent residents occurring during a period of dramatic climate changes. Prof. Sharon, the director of excavations at the Jordan Steps site, explains: "In the study of prehistory, this period is called the Epipaleolithic period. At the beginning of the period, the people are organized in small groups of hunters and hunters who wander around the area. Then, around 15 thousand years before our time, we witness a significant change in lifestyles: the appearance of permanent yeshiva in 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 archaeo-botanist who specializes in identifying plant remains, adds that the second dramatic process in this period is the climatic changes that are occurring in our region. "It is true that at the height of the last ice age, about 5 years ago, the Land of Israel was not covered by a glacial mantle as was the case in other parts of the world, but there were climatic conditions different from the conditions today, the exact characteristics of which were not known until this study. The climate model we built based on the recurrence of fluctuations in the extent of plant species indicates that the main climatic change in our regions was expressed in a drop in temperature (up to 50 degrees Celsius less than today), while the amount of precipitation was similar to today (about XNUMX mm less than the annual average).
However, Dr. Langot explains that later in the Epipaleolithic period, 5,000 years later (about 15 years before our time), a significant improvement in climate conditions is evident in the model. An increase in the prevalence of heat-loving tree species (such as the olive, the common oak and these) indicate an increase in temperature and the amount of precipitation. During this period, the first sites belonging to the Natufian culture appear in our region, and it is very possible that the favorable climate helped the development and prosperity of this culture, in which permanent settlements, stone-built buildings, food storage facilities and more appear for the first time on the global scene.
The next phase of the research deals with the end of the Epipaleolithic period, about 12-11 thousand years ago, known as the Younger Drayas. This is a period of returning to a cold and dry climate like in the ice age, 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 regions and to what extent.
According to the researchers: "The findings emerging from the model presented in the article show that the period was characterized by climatic instability, great volatility and a significant drop in temperatures. However, in the reconstruction of the precipitation, a surprising phenomenon was observed: the reconstructed average amounts of rain were only slightly less than today, but the precipitation was spread over the whole year, including summer rains."
According to the researchers, such dispersal helped the expansion and proliferation of annual and herbaceous plant species. The collectors who lived in this period were now faced with a wide and available variety of plants that could be collected all year round. This variety allowed them to get to know the plants in depth, 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 domestication.
Dr. Langot concludes: "This research contributes not only to the understanding of the environmental background for fateful processes in human history such as the beginning of permanent settlement and the transition to agriculture, but also provides information regarding the history of the area's vegetation and its response to climate changes in the past. There is no doubt that this information may help preserve species diversity and assess current and future climate challenges."
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