A scientific link between volcanic eruptions and climate change has been identified by academics from Queen's University.
Researchers from the school of geography, archaeology and palaeoecology at Queen's were part of an international team that analysed volcanic activity over the last 2,500 years.
They found that eruptions were often followed by periods of summer cooling and, in extreme examples, triggered crop failures and famines across Europe.
The project team found that eruptions have the potential to cause climate cooling, because the aerosols emitted, which can remain in the atmosphere for a number of years afterwards, reflect the sun's heat back into space.
The team included scientists who analysed the chemistry of ice cores from Greenland and Antarctica to construct a record of past volcanic eruptions.
Aerosols, and sometimes particles of ash from the eruptions, were transported in the atmosphere to the polar regions where they were deposited and eventually buried within the ice.
The research team was led by scientists from Nevada's Desert Research Institute (DRI). Its findings have been published in the journal Nature.
Queen's researchers Dr Gill Plunkett and Professor Jonathan Pilcher were involved in looking for traces of volcanic ash deposited in the Greenland ice cores.
"Our findings show that it's not just the large eruptions that we need to think about," said Dr Plunkett.
"A combination of smaller events can have a similar impact on climate as a large event, and the smaller eruptions occur much more frequently than the large ones."