Ask A Scientist© Environmental Science Archive

Author:     kgbard
Text:       How do volcanoes affect the climate both on a local level and on a 
global level? How do they affect temperature, rainfall, and pollution? What 
kinds of gases and particles are emitted and what how do they affect life 
around the volcano?

Response #: 1 of 1
Author:     Mark Fernau
Text:       Volcanoes release carbon dioxide, sulfur dioxide, and other gas 
molecules. Poisonous clouds of gas will suffocate a person caught in them as 
they rush down the volcano side. The sulfur dioxide gets thrown high into the 
stratosphere (where jet planes fly) along with dirt particles. The sulfur 
dioxide gets converted to sulfate particles. These particles reflect sunlight 
back to space which cools Earth's climate. The recent eruption in the 
Philippines cooled the Earth by about one degree F and may have been 
responsible for the cool summer of 1992. The particles spread all around the 
world so the effect is fairly uniform. They also scatter sunlight leading to 
spectacular red sunsets. Volcano particles may lead to more clouds, and thus 
rain, around a volcano but I am not sure about this.