Ancient Irish texts show volcanic link to cold weather

Researchers have been able to trace the impact of volcanic eruptions on the climate over a 1200-year period by assessing ancient Irish texts. The international team compared entries in these medieval annals with ice core data indicating volcanic eruptions. Of 38 volcanic events, 37 were associated with directly observed clod weather extremes recorded in the chronicles.

The report is published in the journal Environmental Research Letters. At monastic centres across the island, recorded significant events such as feast days, obituaries and description of extreme cold and heat. These chronicles are generally known as the Irish Annals and in this report, scientists and historians have looked at 40,000 entries in the texts dating from AD 431and 1649. The researchers also looked at the Greenland Ice Sheet Project ice-core data.  When volcanic erupt, they produce sulphate aerosol particles which down the centuries have been deposited on and frozen in ice sheets, leaving an extremely accurate temporal record of the event.