Emissions from volcanic eruptions are an example of a forcing on the climate system.
Do all volcanic eruptions have an effect on the climate system?
Only volcanic eruptions large enough to force dust up into the relatively stable stratosphere have a significant effect on the world’s climate. Pinatubo, which erupted in 1992, cooled the Earth noticeably for about 2 years.
Is there any uncertainty surrounding past observations of volcanic emissions?
There is a reasonable amount of uncertainty in observations of volcanic emissions in the past – particularly in the pre-satellite era.
How have volcanic emissions been included in climateprediction.net?
For the past 80 years, we have created 5 data sets based on the Sato and Amman observations of volcanic aerosol in the stratosphere. This data is divided into 4 latitude bands of equal area – 90ºS-30ºS, 30ºS to the equator, the equator to 30ºN, 30ºN to 90ºN.
For the future, we have created 10 possible scenarios, as we have, of course, no idea what volcanoes may erupt where. One scenario simply repeats the recent past according to the Sato (2002) data set. Two more are based on observations of the preceding 80 years, based on the Sato and Amman data sets. The remaining 7 are subsets of observations of 1400-1960, based on a data set constructed by Crowley.