(ORDO NEWS) — By analyzing the isotopic composition of fossil mollusk shells found in northern Spain, scientists have assessed the impact of climate change on the lives of ancient people. Global cooling, which occurred 8.2 thousand years ago, led to an increase in the population of coastal regions and caused an increased demand for edible shellfish.
The global warming that we are witnessing now will undoubtedly have repercussions for human history. In the same way, environmental changes greatly influenced the lives of our distant ancestors.
The most serious climate change over the past 11 thousand years is considered to be a cooling event that occurred 8.2 thousand years ago. It was caused by the melting of the North American ice sheet, which resulted in a huge amount of cold fresh water from glacial lakes into the ocean, which changed the global circulation.
The consequences of this event are documented all over the world, but so far its impact on humans has remained poorly understood. Now an international team of scientists has managed to find out some details of the life of people of that time. The results of their research are published in the journal Scientific Reports.
The authors of the work studied the composition of oxygen isotopes in the shells of marine mollusks extracted from the cave of El Mazo (Northern Spain). Archaeological layers are perfectly preserved in this place, reflecting the 1500-year period of time, which included global cooling.
The isotopic composition of the shells made it possible to determine the temperature of the water in which the mollusks lived.
Global cooling has changed the availability of various types of edible shellfish. Thus, the abundance of the heat-loving Phorcus lineatus, which is the most commonly consumed food, has sharply decreased, while the species P. vulgata and P. depressa, which are more resistant to low temperatures, have, on the contrary, multiplied.
The scientists also found out some details about shellfish mining at that time. The decrease in average shell size was indicative of a higher demand for these invertebrates.
This was probably due to a sharp increase in population in areas along the Atlantic coast, which remained the warmest and attracted people from more remote corners of the continent.
However, the foragers who lived in the vicinity of El Mazo still could not completely deplete coastal resources, since the average size of mollusk shells rarely fell below the minimum and guaranteeing the survival of an individual.
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