The impact of volcanic eruptions on the Earth’s climate is being reassessed thanks to new research using Antarctic ice cores.

The study, using 26 ice cores from 19 different sites in Antarctica, provides the most accurate account yet of the number, timing and strength of major volcanic eruptions in the past 2000 years.

Australian Antarctic Division glaciologist, Dr Tas van Ommen, said previous estimates of volcanic activity were imprecise, due to limited measurements from a small number of ice cores.

“We’ve developed a more accurate picture of volcanic activity by looking at the amount of sulphate aerosols deposited in a much larger number of ice core samples than were previously available,” Dr van Ommen said.

“We have been able to provide accurate dating for 86 volcanic eruptions during the past 2000 years by comparing them to a single ice core containing annual layers of climate information.”

Powerful volcanic eruptions inject into the stratosphere large amounts of sulphur dioxide that convert to sulphate aerosols.

This deflects sunlight away from the Earth’s surface leading to short-term global scale cooling.

“This ice core study has allowed us to better estimate the amount of global sulphate aerosols from volcanic eruptions and the subsequent impact on global temperatures,” Dr van Ommen said.

“This information allows us to improve model reconstructions of temperature and climate in the aftermath of volcanic events.

“This is important for understanding the sensitivity of the climate system to natural and human-made atmospheric inputs, to improve climate models that ultimately inform environmental policy decisions regulating greenhouse gas and aerosol emissions.”

The research was conducted by a team of international ice core scientists from Australia, United States, Germany, Norway, Japan and Italy and published in Nature Climate Change today.