By Pablo Colado
A comprehensive study, published in the journal Nature, has found new evidence of the correlation between volcanic eruptions and climate changes over the past 2,500 years.
Carried out by the Desert Research Institute and various international institutions, it has mainly consisted of comparing the presence of volcanic sulfate particles in the deep ice of Antarctica and Greenland with the sudden drops in temperature that left their mark on historical documents and changes in temperature. thickness of tree rings.
Thus, for example, it has been found that 15 of the 16 coldest summers recorded between 500 BC and 1000 AD were preceded by large eruptions, whose dust clouds clouded the atmosphere and attenuated the arrival of solar rays to the earth's surface.
After analyzing 20 ice samples, scientists have been able to determine the levels of sulfate that reigned in the atmosphere in the past, year by year. To do this, they have used a new algorithm that greatly refines the precision of the analysis.
The key to success, say the authors, lies in the study's multidisciplinary approach, in which geologists, climatologists, astronomers and historians have participated.
The latter have traced written testimonies about atmospheric observations such as diminishing sunlight, discoloration of the solar disk, the appearance of solar crowns and the frequency of exaggeratedly red sunsets.
One of the most valuable contributions of the new study has been to elucidate what triggered one of the most serious climate crises in history, which occurred in the sixth century of our era.
In March of the year 536, a mysterious cloud covered the sky of the Mediterranean area, a phenomenon that lasted for 18 months. The cause was, it is now known, a large eruption in the Northern Hemisphere.
In addition, the cooling of the climate was accentuated when, four years later, another volcano woke up somewhere in the tropics.
Summers were exceptionally cold for 15 years, ruining crops and causing terrible famines. In all likelihood, he contributed to aggravating the plague that decimated the population of the Eastern Roman Empire between 541 and 543.