Recent glacier variations and volcanic eruptions

Abstract

The injection of volcanic dust and gases into the atmosphere during major eruptions has been advanced to explain short-term variations of climate1–4. A calculated global cooling of ∼1K during episodes of intense volcanic activity3 could lead to a snowline depression sufficient to cause glacier advances equivalent to those of the last several centuries. The hypothesis would therefore be strengthened if a close relationship could be demonstrated between global volcanicity and the pattern of recent glacier variations. Glacier activity in the Northern Hemisphere during much of the past 100 yr shows a lack of synchrony with that in the Southern Hemisphere, but in each hemisphere the sequence of glacier variations matches the acidity record in polar ice cores and the frequency of volcanic eruptions in successive latitude belts. This suggests that glaciers fluctuate in response to atmospheric build-up of volcanic aerosols produced during large eruptions and that explosive volcanism may therefore be a major factor in modulating climate on the decadal scale.