The effects of major volcanic eruptions such as Laki can also be felt elsewhere on the globe, often far from their actual location.

CNN: How volcanoes can change the world

Benjamin Franklin was one of the first to suggest that the extreme cold of 1783-84 over much of the Northern Hemisphere was connected to the Laki event.

CNN: How volcanoes can change the world

The Laki eruption was believed to have caused thousands of deaths because of unusual conditions in Europe that summer, along with the severe cold of the following winter.

CNN: How volcanoes can change the world

Just such an aerosol effect is believed to have disrupted the Earth's thermal balance during the Laki event, cooling some Northern Hemisphere regions by as much as 1 or more degrees Celsius below the long-term average.

CNN: How volcanoes can change the world

Although the current eruption of Eyjafjallajoekull in Iceland appears not to be comparable in intensity to those of Laki and Tambora, it will have some effects, such as those on air travel, that were never realized back in those simpler times.

CNN: How volcanoes can change the world

In North America, Laki has been blamed for the starvation of Inuit populations from severe cold in northwestern Alaska, based on Inuit oral history as well as tree-ring density data investigated by Gordon Jacoby and others, who estimated that conditions were about 4 degrees Celsius colder than the mean.

CNN: How volcanoes can change the world

For example, significant cooling and strong dynamical effects after the Laki event and other high-latitude eruptions are believed to have caused decreased flow of the Nile River in Egypt and weakened African and Asian monsoons based on climate model simulations, with potentially very significant impacts on food and water supplies.

CNN: How volcanoes can change the world