A group of researchers from Europe and the United States have linked the eruption of the volcano Okmok in Alaska in 43 BC with the deterioration of climatic conditions in the Mediterranean region over the next two years. This probably led to crop failures, famine and disease, which has exacerbated social unrest and contributed to political changes in some States of Western civilization. Article published in the Proceedings of the National Academy of Sciences.
The murder of the Roman dictator Gaius Julius Caesar in March 44 BC marked the beginning of great political turmoil in the Mediterranean, first and foremost, it affected the Roman Republic and the States of the Ptolemies in Egypt. Antique sources and paleoclimate data indicate that these changes have occurred against the backdrop of very unfavourable weather conditions.
Historians have long speculated that the most likely cause of climate change has become a powerful volcanic eruption. The main contenders were considered the volcanoes mount Etna in Sicily, Shiveluch in Kamchatka and Apace in Nicaragua. Joseph McConnell (Joseph R. McConnell) from the desert research Institute in Nevada and colleagues from other research centers in the USA, the UK, Germany, Switzerland, Ireland and Denmark believe that the real culprit in the deterioration of the climate in the Mediterranean has been the Caldera-forming eruption of the volcano Okmok in Alaska in 43 BC.
A team of scientists, which in addition to the climate experts, and historians, used known data of the scientific observations from different regions of the Earth for the reconstruction of climate during this period. For example, analysis of information in tree rings temperature-sensitive trees Austria and Scandinavia showed a marked regional cold (more than three degrees Celsius in the summer) in 43 and 42 BC. Similar data were obtained from annual rings of the bristlecone pine, which grows in the mountain system of California’s White mountains. Experts have identified rare frosty ring, which indicates the anomalous temperature below zero in early September, 43 BC, that is, at the end of the summer growing season in the Northern hemisphere.
Another evidence of abrupt changes in weather conditions in these years — data from speleothem karst caves of Shihua in northeast China. Speleothem — secondary mineral deposits which over time are formed in caves. The study of these deposits in Shihua showed that within three years from 45 BC, there was a decrease in summer temperatures more than two degrees Celsius. The Chinese written documents also indicate unusual cold weather events in 43 and 42 BC, including the late spring and early autumn frosts.