Volcanic findings


Researchers find link between a series of volcanic eruptions from around the world, low Nile floods, and agricultural catastrophe in Ancient Egypt.


Ancient Egypt was always vulnerable to droughts and poor floods, many of them caused by El Niño events in the distant Indian Ocean. But a new generation of research centred at Yale University studying the Ptolemaic period relies not only on historical records, which are often incomplete, also on hydrological and climate modelling as well as ice cores, and now volcanic eruptions.


By examining a long run of climate records, the researchers note that major volcanic eruptions were followed by drops in Nile floods. They focused on the period 168 to 158 BC, a time when Rome was wielding growing power in the eastern Mediterranean, winning an important war against Macedonia in the year 168 BC.


This, and other victories, caused considerable stress on other states in the region, including Egypt. Then four major eruptions, estimated to have occurred in the modern-day Philippines, Iceland, Alaska and eastern Russia, released large concentrations of volcanic ash and sulphate aerosols, cooling the Earth’s atmosphere.


The Northern Hemisphere eruptions caused disruptions in the movement of a tropical zone that causes rain. The cooler atmosphere in the north failed to pull tropical rainfall as far north as usual during the monsoon season. Less rain fell on the Ethiopian highlands, the source of the Blue Nile, resulting in lower Nile floods than usual. The low inundations downstream had a catastrophic effect on irrigation agricultural production on the river floodplain. This happened just as the Romans beat off two attempts to invade Egypt by the Seleucid King Antiochus IV. They were fortunate in their victories, for Rome now relied on Egypt as a major wheat granary.



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Image: The Nile Delta from space, NASA