Overnight, a volcano in Iceland called
erupting, triggering a flurry questions about the possible
impacts for the UK and further afield.
In 2010, Eyjafjallajökull eruption in Iceland
disrupted global transport - shutting down air traffic
across Europe for several days.
Volcanoes also have an effect on the climate.
Throughout earth's history, volcanic eruptions have punctuated the
temperature record. We take a quick look at the role of volcanic
eruptions in climate - past, present and future.
A tiny contribution to global
Volcanic eruptions can affect climate in two main
ways. First, they release the greenhouse gas carbon dioxide,
contributing to warming of the atmosphere.
But the warming effect is
very small. Volcanic carbon dioxide emissions since 1750 are at
least 100 times smaller than those from fossil fuel burning,
according to the latest report from the Intergovernmental Panel on
Climate Change (IPCC).
A two-year cooling effect
As well as carbon dioxide, volcanic eruptions also
blast a cloud of ash, dust and sulphur dioxide into the
stratosphere, which is quickly blown around the globe.
Sulphur dioxide combines with oxygen and water to form
sulphuric acid "aerosols". These particles directly reflect
sunlight and encourage clouds to form.
This cooling effect outweighs the warming contribution from
carbon dioxide, causing an overall cooling that tends to lasts for
about two years after a major eruption.